mccamy@squirt.DEC (07/18/85)
From: "...decvax!decwrl!rhea!Squirt!McCamy" Merrimack, New Hampshire I'm interested in building my own speakers and am not sure what speakers to purchase. I have heard a lot of good things about a company called Speakerlab. Has anyone had any experience with this company? Any recommendations of other companies? I prefer a minimum woofer size of 12", horn type midrange and tweeter, and prefer an acoustic-suspension type system over the bass reflex.
klein@ucbcad.UUCP (Mike Klein) (07/19/85)
> I'm interested in building my own speakers and am not sure what speakers to > purchase. I have heard a lot of good things about a company called > Speakerlab. Has anyone had any experience with this company? This group has been over this quite a bit recently. The thing to do is get reference sources. There appear to be two main ones: a book by Martin Colloms called "High Performance Loudspeakers," and a magazine called Speaker Builder. I recently bought the Colloms book, and it is excellent, for novices or experts. I have had good experiences with Speakerlab but others on the net haven't, in particular that their drivers didn't measure out to published specs and weren't consistent. > I prefer a minimum woofer size of 12", horn type midrange and tweeter, and > prefer an acoustic-suspension type system over the bass reflex. Are your preferences based on solid facts or religion? In other words, have you done enough research to decide on implementation already? From your earlier quote, I would say probably not. If you have, never mind. For instance, if you want great fidelity, horns won't do. If you want high efficiency, horns are the best choice. And if you're looking for extended bass response AND high efficiency, enclosure volume is the main determining factor. On the other hand, if you want massive sound volume you want a big woofer. Etc., etc. It's all very complicated. -- -Mike Klein ...!ucbvax!ucbmerlin:klein (UUCP) klein%ucbmerlin@berkeley (ARPA)
rdp@teddy.UUCP (07/19/85)
In article <3177@decwrl.UUCP> mccamy@squirt.DEC writes: >From: "...decvax!decwrl!rhea!Squirt!McCamy" >Merrimack, New Hampshire > > >I'm interested in building my own speakers and am not sure what speakers to >purchase. I have heard a lot of good things about a company called >Speakerlab. Has anyone had any experience with this company? > >Any recommendations of other companies? > >I prefer a minimum woofer size of 12", horn type midrange and tweeter, and >prefer an acoustic-suspension type system over the bass reflex. I am afraid that the requirements you set out for the components are quite incompatible! First of all, there will be a wild mismatch in efficiency between the bass and mid/treble units, possibly more than an order of magnitude! This is not only going to cause problems with overall frequency response, but the crossover is going to be a pain to do. The primary advantage to horn units is efficiency, but your going to have to throw away every bit of that advantage in the crossover to get the units to match out-put-wise. Secondly, the overall response characteristics of horns tends to be much poorer than that of good direct drive units, claims of manufacturers (JBL, etc) and horn afficianados not withstanding. In experiments performed when I was working for JBL and later as an independent consultant, it was decided that it was impossible to physically realize a horn driver with anything approaching the frequency/phase/dispersion linearities of suitable direct drivers. (Please don't flame me for this, as I am sure I have spent much longer working on this and similar problems than the vast majority of people, including most "speaker engineers", and I don't have the time to respond to incensed replies. Reasonable queries is something different, though). About SpekerLabs, I have little direct information. For direct drive units, I am familiar with the Dalesford importer, and can recommend some of there units highly, if they are still available.
smithson@calma.uucp (Brian Smithson) (07/19/85)
> From: "...decvax!decwrl!rhea!Squirt!McCamy" > Merrimack, New Hampshire > > > I'm interested in building my own speakers and am not sure what speakers to > purchase. I have heard a lot of good things about a company called > Speakerlab. Has anyone had any experience with this company? > > Any recommendations of other companies? > > I prefer a minimum woofer size of 12", horn type midrange and tweeter, and > prefer an acoustic-suspension type system over the bass reflex. I used to live in Seattle, when Speakerlab was still "local". They had a great reputation then, and as far as I know they are still great. My only experience has been with their bookshelf-sized speakers, and they are excellent (especially in their price range!). People I knew who had their larger speakers were also pleased. Do check them out. -- -Brian Smithson Calma Company ucbvax!calma!smithson calma!smithson@ucbvax.ARPA
knf@druxo.UUCP (FricklasK) (07/19/85)
I have had very good luck with Speakerlab, but I have found
better drivers (and less expensive) from Gold Sound in Denver (
(another mail order company).
They're address is:
P.O. Box 141
Englewood, Colo.
80151
Phone: (303)789-5310
'`'`
Ken
'`'`
PS I am in no way affiliated with Gold Sound, I just use their drivers...knf@druxo.UUCP (FricklasK) (07/22/85)
I agree in general about horns, but as far as effieciency, ever heard of horn loaded woofers? '`'` Ken '`'`
kyl@ttrdc.UUCP (Kwing Y. Lee) (07/23/85)
Dear Ken: In reply to your question about horn loaded woofers. I have owned a pair of KLIPSCH speakers for about 9 years and have heard many of the "newer" speakers. My speakers are fully horn loaded, including the 15" woofer that is buried inside the enclosure in a folded horn structure. The bass response is (in my OPINION) the best that I have ever heard in a home speaker system. There are a few disadvantages though, they are very large and very complex to build. I do not recommend for anyone to build large fold horn enclosures. However, there are straight horns that you can build fairly easily. The one that I would recommend is Altec Lansing's voice of the theater enclosure designed to load a 15" woofer with a short exponential horn. I would like to see comments from other netters on this subject as well.
rdp@teddy.UUCP (07/23/85)
In article <914@druxo.UUCP> knf@druxo.UUCP (FricklasK) writes: >I agree in general about horns, but as far as effieciency, ever heard >of horn loaded woofers? > '`'` > Ken > '`'` Of course, the dreaded Klipsch horns. There is a classic example of a design taken to it's absurd conclusion. The most certainly are efficient, one person even suggesting that they could run the speakers at reasonable levels off the output of their preamp with a suitable matching transformer. However, they suffer from a staggering array of other problems, not the least of which is the fact that the woofer driver is about 5 or 6 feet farther away than the mid range driver, which is about a foot behind the tweeter driver (as all of these drivers sit at the back of the horns). The result time and phase anomolies aroud the crossover networks lead to some interesting, albeit inaccurate, reproduction effects. There is also the ad which appeared in an early 1970's Hi-Fi News and Record Review (from Britain) which went something like: "Complete horn loaded stereo speaker system consisting of 2 massive 12 foot STRAIGHT concrete horns, horn KEF midrange and IonoFane treble units. Excellent fidelity. Comes complete with 2 bedroom home with eat-in kitchen, large rear garden... " Ah, the British! Dick Pierce
rfg@hound.UUCP (R.GRANTGES) (07/24/85)
[] In my opinion the Altec short front loaded horn in combination with its bass reflex cabinet and horn loaded mid-range and tweeter is the best sounding speaker for large audiences I have heard yet. I have used a pair of A-7's for some 7 or 8 years now and haven't heard them equaled. I also love the Klipsch Corner horn, but could never afford them - or have the space for them. I had to eventually go for smaller speakers, AR-9s (:-) One problem with both horn loaded speakers: they go down a long way and are very musical, but they both poop-out before you get to the really low-down bass. I once heard an AR-1 and a Klipsch played together from the same amp with the same driving voltage (simultaneously). For 99% of the music the Klipsch out-shouted the AR by 20 db or so. Except every time the organ went "woof!", suddenly the Klipsch was silent and it was the little AR-1 that shook the room. Now, I do like 99% of music (well, 98%), but I dote on the "woof." ....a Klipsch with a sub-woofer...?? Dick Grantges hound!rfg -- "It's the thought, if any, that counts!" Dick Grantges hound!rfg
mike@smu (07/25/85)
Just thought I'd suggest that a smaller woofer is often less prone to distorsion, and is often capable of a tighter sound... M.H.P.
saf@bonnie.UUCP (Steve Falco) (07/25/85)
I built a set of "SpeakerLab K's" using the plans available from SpeakerLab. It is not a trivial project (about 50 hours cutting and gluing) but it isn't hard if you are careful. I did most of the crazy compound angle cuts using a hand-held circular saw and an aluminum guide clamped to the wood (mahogany marine grade plywood). I find this more accurate that a tablesaw or radial arm saw. I did need a tablesaw to make the really small pieces that I couldn't safely set up and also for the few pieces with angles greater than 45 degrees. I agree with the previous article that the horns give a superb bass response but I'm not too sure I would want a straight horn in the bass. The problem is that it gets kind of long and you start getting a time delay between the bass and midrange. The folded horn is shorter and (to me) the time skew is not noticeable. Steve Falco
9221mac@hou2f.UUCP (M.CARLETTA) (07/25/85)
Glad to see renewed interest in speaker building on the net. After 9 mos. of scattered work on weekends I've finally completed my latest set, a 3 way system using 18db/octave passive crossovers. The crossovers were optimized by making impedance measurements of each driver, no Zobel networks were necessary; all crossover parts were within 1% of the calculated value, and film caps were used liberally. It consists of a 12" Dynaudio woofer in a 3' high pentagonal column (fourth order alignment). The mids and highs are handled by ferrofluid damped Morel drivers mounted on a 2" thick, flat trapezoid which is attached to the top of the column. The bottoms are made of heavily braced industrial flake board covered with beautiful red oak veneer. The tops are made of solid oak. The sound compares well with commercially available speakers in the $1500 - $2000 per pair price range. The imaging is not quite as good as my 24db/octave tri-amped system. In order to encourage speaker building, I've put together a two page fact sheet with names and addresses of suppliers, and pointers to construction information. I'll send it to anyone who sends me an SASE, and promises to let me know when they succeed. Steve Johnson 113 Wynnewood Ct. Freehold, NJ 07728 (201) 577-0271
keithe@tekgvs.UUCP (Keith Ericson) (07/25/85)
In article <294@ttrdc.UUCP> kyl@ttrdc.UUCP (Kwing Y. Lee) writes: >I have owned >a pair of KLIPSCH speakers for about 9 years and have heard many of the >"newer" speakers. My speakers are fully horn loaded, including the 15" >woofer that is buried inside the enclosure in a folded horn structure. >...There are a few disadvantages though, they are very >large and very complex to build. I do not recommend for anyone to build >large fold horn enclosures. I have a detailed set of construction plas for Klipschorns that I could make copies of for anyone masochistic enough to try it. I *think* I have the plans for the SpealerLab "Super K" (I think that's the name) which is/was their version of the Klipschorn., but they must be at home 'cause they're not in my file drawer here at work. -- Keith Ericson at TekLabs (resident factious factotum) Tektronix, PO 500, MS 58-383 Beaverton OR 97077 (503)627-6042 uucp: [ucbvax|decvax|ihnp4|(and_many_others)]!tektronix!tekgvs!keithe CSnet: keithe@tek ARPAnet: keithe.tek@rand-relay
rdp@teddy.UUCP (07/29/85)
In article <512@bonnie.UUCP> saf@bonnie.UUCP (Steve Falco) writes: >I built a set of "SpeakerLab K's" using the plans available from >SpeakerLab. It is not a trivial project (about 50 hours cutting and >gluing) but it isn't hard if you are careful. I did most of the crazy >compound angle cuts using a hand-held circular saw and an aluminum guide >clamped to the wood (mahogany marine grade plywood). I find this more >accurate that a tablesaw or radial arm saw. I did need a tablesaw to >make the really small pieces that I couldn't safely set up and also for >the few pieces with angles greater than 45 degrees. > WOW! You either have the best hand-held circular saw ion the universe or the worst tablesaw or radial-arm saw possible! >I agree with the previous article that the horns give a superb bass >response but I'm not too sure I would want a straight horn in the bass. >The problem is that it gets kind of long and you start getting a time >delay between the bass and midrange. The folded horn is shorter and (to >me) the time skew is not noticeable. > > Steve Falco Sorry Steve, It doesn't make any difference wether the horn is folded or straight, the propogation delay through the horn is still proportional to the overall length. 10 feet is 10 feet, whether or not you are going around corners. What you might be refering to is the fact that all the bends cause more anomolies at higher frequencies that might mask what is an already severe problem. By the way, is anyone aware that the propogation velocity through the horn is less than that in free air, making the time delay problem more severe than you might at first think, and that it is also frequency dependent? Dick Pierce
rdp@teddy.UUCP (07/29/85)
In article <28400013@smu> mike@smu writes: > >Just thought I'd suggest that a smaller woofer is often less >prone to distorsion, and is often capable of a tighter sound... >M.H.P. Why? First of all, for a given sound pressure level, the amount of excursion (displacement) is proportional to the inverse square of the radiating area, so that at a given frequency, an 8 inch woofer must have a total excursion TWICE that of a 12 inch woofer. Now it turns out that the way that the VAST majority of drivers are manufactured, small speakers are subject to the same mechanical and electromagnetic limits that large ones are. This would then imply that the smaller drivers have higher levels of mechanically (due to non-linearities in the suspension) and electromagnetic (due to the size of the linear protion of the magnetic field, the LENGTH of the voice coil) induced distortions. Also, because of there lower masses, smaller cones have higher fundamental resonances than larger ones. THis also implies (under normal circumstances) that these mechanical limits will be reached at higher frequencies, where more real music is occurring. As far as control over a cone is concerned, then I quote on of my many laws of acoustics, "The right amount of magnet is the right amount of magnet". Smaller woofers tend to be severely electro-magnetically overdamped, resulting in over-controlled and, as a result, relatively reduced bass performance. This requires either tailoring the response of the input signal, further exacerbating the excursion problem, or wieghting the cone to make it more massive (the "Mortite" syndrom) reducing efficiency, etc., etc., etc.,..... It might be argued that smaller cones have less breakup problems at higher frequencies. ALl things being equal, this is true, but much of this is controllable by appropriate materials technology. It turns out that the most commonly used cone material, paper, is markedly unsuited for loudspeaker use (more on this if anybody is interested) Now smaller cones do have a distinct advantage in angular dispersion characteristics. If this is what you are talking about, then I agree. However, one distortion that smaller speakers do reduce is the distortion of ones living space due to the significantly reduce floor space. :-)
rdp@teddy.UUCP (07/29/85)
In article <1036@teddy.UUCP> rdp@teddy.UUCP (Richard D. Pierce) writes: > >First of all, for a given sound pressure level, the amount of excursion >(displacement) is proportional to the inverse square of the radiating >area, so that at a given frequency, an 8 inch woofer must have a total >excursion TWICE that of a 12 inch woofer. OOOPS, what I meant to say was the amount of excursion is proportional to the inverse square of the DIAMETER of the driver, not the area. But the example I give is correct, as I was computing the areas there. What we are trying to do is maintain a given "volume velocity" for a given sound pressure level so that: Volume Velocity = radiating area x velocity and since the area is proportional to the square of the diameter, the necessary velocity is reduced by the square of the diameter. For a given frequency, the total displacement is proportional to velocity, etc., etc., Sorry... Dick Pierce
eric@rtech.UUCP (Eric Lundblad) (07/30/85)
> I once heard an AR-1 and a Klipsch played together from the same amp > with the same driving voltage (simultaneously). For 99% of the music the > Klipsch out-shouted the AR by 20 db or so. Except every time the organ > went "woof!", suddenly the Klipsch was silent and it was the little AR-1 > that shook the room. > Now, I do like 99% of music (well, 98%), but I dote on the "woof." > ....a Klipsch with a sub-woofer...?? > This is because most horns, including the Klipschs, are designed to go down to about 40 Hz. or so. However, I have plans for a full 20 Hz. horn that's only 9 feet tall and 16 feet long. Now THAT'S something that will blow your doors off. -- Eric Lundblad ucbvax!mtxinu!rtech!eric
eric@rtech.UUCP (Eric Lundblad) (07/30/85)
> I agree with the previous article that the horns give a superb bass > response but I'm not too sure I would want a straight horn in the bass. > The problem is that it gets kind of long and you start getting a time > delay between the bass and midrange. The folded horn is shorter and (to > me) the time skew is not noticeable. All other things being equal, the time delay a horn introduces is the same whether the horn is straight or folded. Sound will take just as long to exit a horn when it twists and turns as it does when it heads straight out. -- Eric Lundblad ucbvax!mtxinu!rtech!eric
levy@ttrdc.UUCP (Daniel R. Levy) (08/02/85)
eric@rtech.UUCP (Eric Lundblad) <579@rtech.UUCP>: > >> I agree with the previous article that the horns give a superb bass >> response but I'm not too sure I would want a straight horn in the bass. >> The problem is that it gets kind of long and you start getting a time >> delay between the bass and midrange. The folded horn is shorter and (to >> me) the time skew is not noticeable. > > All other things being equal, the time delay a horn introduces >is the same whether the horn is straight or folded. Sound will take just >as long to exit a horn when it twists and turns as it does when it heads >straight out. > >-- > > Eric Lundblad > ucbvax!mtxinu!rtech!eric Been thinking about this (the horn delay problem) for a while, and I wonder-- suppose if the non-horn speaker were set back far enough in the cabinet that the delays were equalized? (I guess this would call for a pretty deep cab- inet in the case of a folded horn, but for a straight one why would it need to be much deeper than for the horn alone? Just build a "wall" surrounding the passage from the non-horn to the front of the cabinet (actually you have just created another "horn" this way); vent the rear to the inside of the rest of the cabinet.) -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer, my pets, my plants, my boss, or the | at&t computer systems division | s.a. of any computer upon which I may hack. | skokie, illinois | | "go for it" | Path: ..!ihnp4!ttrdc!levy -------------------------------- or: ..!ihnp4!iheds!ttbcad!levy
klein@ucbvax.ARPA (Mike Klein) (08/02/85)
It is generally recognized that smaller woofers have more distortion than larger ones, all other things being equal. And this is indeed why: > This would then imply that the smaller drivers have higher levels > of mechanically (due to non-linearities in the suspension) and electromagnetic > (due to the size of the linear protion of the magnetic field, the LENGTH > of the voice coil) induced distortions. And on to some other interesting things about woofers... > Also, because of there lower masses, smaller cones have higher fundamental > resonances than larger ones. Fundamental resonance is determined mainly by the cone and voice coil mass and the suspension compliance. Note that small woofers usually have very soft suspensions and larger ones usually have stiffer suspensions. On the whole, smaller woofers have a higher fundamental resonance, but the difference may not be nearly as much as you'd expect. > Smaller woofers tend to be severely electro-magnetically > overdamped, resulting in over-controlled and, as a result, relatively > reduced bass performance. This requires either tailoring the response > of the input signal, further exacerbating the excursion problem, or > wieghting the cone to make it more massive (the "Mortite" syndrom) > reducing efficiency, etc., etc., etc.,..... Small woofers are massively overdamped because they are designed to go in a small box which raises the system's overall Q more than a larger box would. This is not a design defect! It is also not the real reason why efficiency suffers. Efficiency, system cutoff frequency, and box volume are the three fundamental factors that must be traded off, and it's not very fair to the frequency: best efficiency = (constant) * (box volume) * (cutoff frequency ^ 3) A woofer in a small box trying to have a low cutoff frequency is *fundamentally* constrained to have a low efficiency. It actually does not depend on the woofer size. (this equation holds for free-field radiation.) > It might be argued that smaller cones have less breakup problems at > higher frequencies. ALl things being equal, this is true, but much > of this is controllable by appropriate materials technology. It turns > out that the most commonly used cone material, paper, is markedly > unsuited for loudspeaker use (more on this if anybody is interested) This is really true! Recent research has shown that newfangled materials can actually behave very well through the breakup region. Paper is not one of them. Bextrene and polypropylene are very good. Also -- The "tightness" of the bass has nothing to do with size of the woofer, but with the overall damping of the woofer system. However, some people may assign the word "tightness" to a frequency response that emphasizes the 60-100 Hz range, because that's the frequency range that hits your gut hardest. The typical smaller woofer in a smaller box may very well have this kind of frequency response, and may appear to have a "tight" bass.
man@bocar.UUCP (M Nevar) (08/02/85)
> This is because most horns, including the Klipschs, are designed to >go down to about 40 Hz. or so. However, I have plans for a full 20 Hz. horn >that's only 9 feet tall and 16 feet long. Now THAT'S something that will blow >your doors off. >-- I have just ordered a pair of sub-woofers from a private low-yield speaker and electronic manufacturer in New Jersey. Each is about a 2-foot cube. With all the internal baffling and channeling, the speaker (actually a self-made 15-inch woofer) produces an effective horn length of 38 FEET ! This speaker can be driven to as low as 2 Hz ! This is not a low peak, but has actually driven pink noise at 2 Hz for short periods of time. This set-up has forced the maker to re-inforce his listening room. Mark Nevar
saf@bonnie.UUCP (Steve Falco) (08/05/85)
I maintain my earlier statement: I can work more accurately with the hand circular saw. For one thing, I am manipulating a light saw rather than an awkward sheet of plywood. Also, if I set the guide on the "work side", rather than the "scrap side" then if I run off, the worst that can happen is that the piece is slightly too large. This can be corrected by simply running the saw along the guide again. In all that cutting (over 100 pieces) I spoiled exactly zero pieces. I ran off a few times but only into the scrap. And yes, the circular saw is a very high quality unit. About the horn length. There are several variables. One is that the horn length can be shorter in some designs than others. It is the mouth area that sets the low frequency cut off. The Klipsh design uses a much shortened horn as compared to the bulk of the straight horn designs. It's not perfect but after living with it for several years I contend that I have yet to hear anything as satisfying. Steve Falco
rdp@teddy.UUCP (08/06/85)
[] In reply to my discussion about small woofers (see referenced article: In article <9570@ucbvax.ARPA> klein@ucbvax.UUCP (Mike Klein) writes: >It is generally recognized that smaller woofers have more distortion >than larger ones, all other things being equal. And this is indeed why: > "Generally recognized" does not constitute "proven in fact", as we shall see.. > >Fundamental resonance is determined mainly by the cone and voice coil mass >and the suspension compliance. Note that small woofers usually have very soft >suspensions and larger ones usually have stiffer suspensions. On the whole, >smaller woofers have a higher fundamental resonance, but the difference may >not be nearly as much as you'd expect. > Yes, fundamental resonance is a function of total mechanical stiffness and the inverse of total moving mass, but, I'm afraid, the assumption that small woofers usually have soft suspensions is not so. If you have specific product data to back your claim, fine. I do, on the order of about 800 samples of drivers. One way of measuring true effective compliance is to specify what is refered to as the "equivalent volume of compliance". This is the restorative force presented by an enclosed vloume of air that is the same as the mechanical stiffness of the woofer. Let's take two relatively well known drivers from KEF in England. The 5 inch B110 (the same driver used in the BBC LS3-5A) has an equivalent compliance volume of about 7.5 liters, whereas the B200, an 8 inch driver having the same spider assembly, the same magnet and voice coil, and the same suspension cross section, as a figure more like 25 liters. There are, in my archives, nearly 150 other examples that I refuse to bore the network with. Most driver manufacturers do not make their suspensions, but buy them from a variety of sources such as Mueller, Seas, and so forth. Their own product data do not support the above claims. Note also, that within a given manufacturers line, the same spider assembly is used, and that is often the overriding source of stiffness. Let's also look at this from another viewpoint. If you look at a range of suspensions from someone like Mueller, you find that the cross-sections are the same, regardless of diameter. This would imply that the stiffness per linear run of suspension is uniform. This further implies that the stiffness of a suspension is proportional to its diameter. However, the mosing mass is proportional to the square of the diameter. This would then mean that for a given range of drivers (say from KEF or Dalesford or what have you) that the fundamental resonance is a function of the square root of the diameter, because of the compliance, and the inverse of the diameter, because of the mass. Low and behold, it turns out the the mass becomes the more important term. Interestingly enough, the manufacturers product data supports this fully. I have this data for about 45 manufacturers, and have confirmed it for most, have you? > >Small woofers are massively overdamped because they are designed to go >in a small box which raises the system's overall Q more than a larger box would. Wrong, small woofers, in the vast majority of cases, are overdamped because it is more economical for a driver assembler to stock fewer diverse magnet assemblies. This I know because I once was intimately involved with several of them. To go one step further, most small high-quality drivers are to far overdampled for any practical sized enclosures. Case in point. The Dalesford d110 has an equivalent compliance volume of about 8.3 liters, and a system Q of about .22 with a 40 cycle resonance. Now, the final system aparameters can be determined by square root of the ratio of the driver compliance to box compliance. Let's seek a target system Q of .7, which is the best compromise of maximally flat, minimal phase error, etc, etc (i.e. Butterworth characteristics) In order to achieve this, we need a driver Q to system Q ratio of .7/.22 or roughly 3. Refering to the experts (Small, JAS about 78 or so), we find that that requires a ratio between driver compliance and box compliance on the order of 8 or 9, meaning that the box must be about 1 liter in size. This is smaller than the driver itself. On the other hand, one variant of the KEF b110 has a system Q of .5, which when combined with a box of about 7 or 8 liters, results in a system whose Q is around .7, cutoff is about 70 Hz, etc. In practice, I have found through manufaterers data sheets and my own extensive testing, that small, high quality woofers are far to overdamped to be usable as bass drivers. Ain't nuthin like REAL data, is there? :-) >This is not a design defect! It is also not the real reason why efficiency >suffers. Efficiency, system cutoff frequency, and box volume are the three >fundamental factors that must be traded off, and it's not very fair to >the frequency: > > best efficiency = (constant) * (box volume) * (cutoff frequency ^ 3) > >A woofer in a small box trying to have a low cutoff frequency is >*fundamentally* constrained to have a low efficiency. It actually >does not depend on the woofer size. (this equation holds for free-field >radiation.) > Why is it independent of diameter? Because your asking this little tiny woofer to do far more excursing to produce a given sound level, thus driving it farther into it's non-linear operating regions! > >>re: use of non-paper materials in loudspeakers to prevent breakup, etc. > >This is really true! Recent research has shown that newfangled materials >can actually behave very well through the breakup region. Paper is not >one of them. Bextrene and polypropylene are very good. > Recent? KEF was using Bextrene (polystyrene with a rubber over-coat) in the 60's. My experimentation with polypropylene was done in 1972. Ho-hum, more breakthroughs.... > >Also -- The "tightness" of the bass has nothing to do with size of the >woofer, but with the overall damping of the woofer system. However, >some people may assign the word "tightness" to a frequency response that >emphasizes the 60-100 Hz range, because that's the frequency range that >hits your gut hardest. The typical smaller woofer in a smaller box >may very well have this kind of frequency response, and may appear >to have a "tight" bass. Gee, I hope your not accusing ME of saying that!!! :-) The upshot of all of this is that is seems that a lot of so-called information seems to be rumor, guessing and so forth. I am not necessarily accusing the above respondant of such, but my original remarks are base od quite a bit of real research. I have probably 10 feet of experimental data to extract my conclusions from. I do not expect results, I measure them. Only after there is a considerable body of experimental data to prove or disprove something do I (and should anyone) make a conclusion. In the above case, some of the respondants conclusions might well be intuitively correct, but real product data proves otherwise. Sorry. Dick Pierce
rdp@teddy.UUCP (08/06/85)
In article <228@bocar.UUCP> man@bocar.UUCP (M Nevar) writes: > >> This is because most horns, including the Klipschs, are designed to >>go down to about 40 Hz. or so. However, I have plans for a full 20 Hz. horn >>that's only 9 feet tall and 16 feet long. Now THAT'S something that will blow >>your doors off. >>-- > >I have just ordered a pair of sub-woofers from a private low-yield speaker >and electronic manufacturer in New Jersey. Each is about a 2-foot cube. >With all the internal baffling and channeling, the speaker (actually a >self-made 15-inch woofer) produces an effective horn length of 38 FEET ! >This speaker can be driven to as low as 2 Hz ! This is not a low peak, >but has actually driven pink noise at 2 Hz for short periods of time. >This set-up has forced the maker to re-inforce his listening room. > >Mark Nevar Boy, I hope whoever you ordered them from has a cancellation policy or a money back policy, because, methinks, you just bought some snake oil. Why? The cutoff frequency of a horn is dependent upon the size of the mouth of the horn, and somewhat less upon it's length. Also, the efficiency is dependent upon the taper characteristics of the horn. It is, I assure you, impossible to fit a horn capable of doing what is claimed inside a 2 cubic foot enclosure. Look, for example, a Klipsch's. For abvout a 50 Hz cutoff, the have an enclosed volume of (I estimate) about 8 cubic feet and, while they have some severe problems, they really do make it to 50 Hz or so, where they die like a lead balloon. The above is a great simplification of course, but there is no way that the physics will allow the speaker your refering to to do the job that is claimed for it. Dick Pierce
kyl@ttrdc.UUCP (Kwing Y. Lee) (08/06/85)
Dick:
When I first purchased the Klipsch speakers time and phase coherence were
just started to be the main design goals of speakers (Dalquist DQ10s). Back then
the criticisms that I heard about the Klipsches are that they are too big, too
expensive and they don't have the high end response that they should have....
and also the so called "horn sound". Now nearly 10 years later, I still have not
outgrown by babies and I still think they sound fantastic. I would really
appreciated if you can summarized all the criticisms of Klipsch horn speaker
systems in one single comprehensive article. Thanks in advance.
Kwingkyl@ttrdc.UUCP (Kwing Y. Lee) (08/06/85)
Dear Mark:
Please be more specific about the specs on the subwoofers and where you got them
from!
Thanks.
Kwingkyl@ttrdc.UUCP (Kwing Y. Lee) (08/06/85)
Hey Steve, have you ever compare your speakerlab Ks with the real Klipschorns? How
do they compare in your opinion? Are you offended by the "horn sound"?
Kwingklein@ucbvax.ARPA (Mike Klein) (08/06/85)
>One way of measuring true effective compliance is to specify what is refered >to as the "equivalent volume of compliance". This is the restorative force >presented by an enclosed vloume of air that is the same as the mechanical >stiffness of the woofer. This volume (Vas) takes the area of the diaphragm into account and plain suspension compliance does not. This is because an equal movement of a larger diaphragm displaces more air; a larger value of Vas is required to simulate the same suspension stiffness. Your example of the two KEF drivers with identical suspensions bears this out. Fundamental resonance is calculated from suspension compliance and moving mass and does not depend on Vas. Vas is a useful abstraction for calculating enclosure volume later on. >Low and behold, it turns out the the mass becomes the more important >term. Interestingly enough, the manufacturers product data supports this >fully. I have this data for about 45 manufacturers, and have confirmed it for >most, have you? Yes I have. It does not invalidate anything I said, though... >>Small woofers are massively overdamped because they are designed to go >>in a small box which raises the system's overall Q more than a larger box would. >Wrong, small woofers, in the vast majority of cases, are overdamped because >it is more economical for a driver assembler to stock fewer diverse magnet >assemblies. This I know because I once was intimately involved with several >of them. A few years ago, I evaluated a large number of different drivers for woofer applications. I limited my evaluation to drivers that were good candidates for woofers. An interesting thing I noticed is that older product lines tend to consist of all the combinations of a few components (suspensions, magnets, voice coils, cones) and this is where you get some pretty bizarre parameter combinations. Newer product lines have evolved with Thiele's and Small's work and tend to consist of fewer drivers that are optimized for specific applications. These are overdamped because their application demands it. >In practice, I have found >through manufaterers data sheets and my own extensive testing, that small, >high quality woofers are far to overdamped to be usable as bass drivers. Depends on the requirements! If you want a tiny woofer in a tiny box, you must settle for either low efficiency or a high bass cutoff frequency, or both. The KEF B110 is great down to 60-70 Hz. If this satisfies your requirements then this is the woofer you should use (it *is* an excellent unit). >>A woofer in a small box trying to have a low cutoff frequency is >>*fundamentally* constrained to have a low efficiency. It actually >>does not depend on the woofer size. >Why is it independent of diameter? Because your asking this little tiny >woofer to do far more excursing to produce a given sound level, thus >driving it farther into it's non-linear operating regions! This gets us back to my statement in the very beginning, that it is generall accepted that smaller woofers distort more than larger ones, all other things being equal (the other things being efficiency and cutoff frequency). >>Also -- The "tightness" of the bass has nothing to do with size of the >>woofer, but with the overall damping of the woofer system. >Gee, I hope your not accusing ME of saying that!!! :-) No, I'm not; it was in reference to the original article that started this. >The upshot of all of this is that is seems that a lot of so-called >information seems to be rumor, guessing and so forth. I am not necessarily >accusing the above respondant of such... Good! -- -Mike Klein ...!ucbsim:klein@ucbvax.uucp klein%ucbsim@berkeley.arpa
mohler@drune.UUCP (MohlerDS) (08/08/85)
Klipsch speakers have (like all other speakers) a mix of good and bad points, that they chose when balancing variables designing a speaker. To start on a positive note, the Klipsch corner horns have: 1) Very close to the best construction quality of any speaker made 2) A very good older design cross-over with excellent parts quality 3) Very low bass distortion 4) Tremendous efficiency 5) Good quality horn drivers On the negative side: 1) They are billed as the ultimate horn loaded production speaker, which they are not. If you read some of Paul Klipsches early work, you will find that he states to cover a 9 octave range (40 hz to 20480 hz) you typically need 5 horn loaded drivers to get really smooth frequency response. The Electrovoice Patrician P800 (which is quite arguably the best horn loaded production speaker ever made) does just that. It uses an electrovoice W30 30 Inch (no that isn't a typo) woofer into a short horn facing the corner of the room, above that they used an EV SP12B 12 Inch "low midrange" driver in another short horn facing forward, then they used an EV 350 series driver into a large midrange horn, (this is the same midrange as the K-Horn) then they used a smaller 350 series driver into a series 12 horn, and they topped the whole thing off with a T-350a horn tweeter. This yielded awesome sound that was quite linear. Note the previous description was typed from memory from having seen the guts in 1973 when I was 14, so if some of the driver numbers are wrong don't flame at me! The K-horn has some very serious response dips between its 3 drivers and at the low end (below 50 hz). 2) The speaker did not take advantage of the new horn design curves like: hyperbolic and tractrix contours (see good article by Dr. J. Dinsdale published in KEF's speaker publications on these designs). This means that the distortion was not as low as it could be. Much of the "horn - sound" goes away when you loose the abrupt discontinuity at the horn edge by using a tractrix contour. 3) The speaker did not take advantage of the new woofer materials like bextrene and polypropylene, which prevents the driver from being as durable as the rest of the speaker. It also prevented the bass from being less colored. 4) The cross-over has also not been updated to a fourth order Linkwitz - Riley or similar crossover, to help smooth some of those dips between drivers. So really what is bad about the K-horn is that it fails to live up to the potential the concept had. It really could have been the ultimate horn speaker! In 1980 at the CES show Kenwood showed an amazing 10,000. dollar horn speaker that was basically a high-tech revision of the Patrician 800. To those that don't think a horn loaded speaker can't sound musical, you should have heard this giant, it was absolutely incredible! I intentionally avoided a discussion of how good or bad horns sound compared to other speaker designs since it really comes down to what a person can and cannot hear, what a person likes etc. A really good horn speaker can sound very good - and the K-Horn could be alot better than it is. A fundamental objection to horn loaded speakers on my part is the efficiency! It doesn't make sense to me to play any speaker at a level that over time will damage my hearing, and that kind of volume (and small amps) were the reason such speakers were designed. So there you have one set of pros and cons about the horn loaded design principle. David S. Mohler AT&T - ISL @ Denver drune!mohler or druxu!mohler
rfg@hound.UUCP (R.GRANTGES) (08/08/85)
[] What "horn sound?" Do you mean that full range, smooth, low distortion, crisp and solid sound? Gee, I guess I like it. -- "It's the thought, if any, that counts!" Dick Grantges hound!rfg
mohler@drune.UUCP (MohlerDS) (08/09/85)
In my article on horn speakers, there is one fairly major typo, although my message may still have been clear. "To those that [don't] think a horn loaded speaker can't sound musical, you should have heard this giant, it was absolutely incredible." The [don't] should not have been there. David S. Mohler AT&T - ISL @ Denver drune!mohler or druxu!mohler
caf@omen.UUCP (Chuck Forsberg WA7KGX) (08/11/85)
In article <334@ttrdc.UUCP> kyl@ttrdc.UUCP (Kwing Y. Lee) writes: >Dick: > > When I first purchased the Klipsch speakers time and phase coherence were >just started to be the main design goals of speakers (Dalquist DQ10s). Back then >the criticisms that I heard about the Klipsches are that they are too big, too >expensive and they don't have the high end response that they should have.... >and also the so called "horn sound". Now nearly 10 years later, I still have not >outgrown by babies and I still think they sound fantastic. I would really >appreciated if you can summarized all the criticisms of Klipsch horn speaker >systems in one single comprehensive article. Thanks in advance. > About 1975 I decided it was time to upgrade my speaker system as the drivers on my AR3's were getting either fried or rotted away. I make a tape with segments from various records and went to as many stores as I could find. The Klipschorns sounded great on some of the chamber music, but shrieked on the choral music. A Yamaha bookshelf system sounded fine, but was only slightly more efficient than a dummy load. Magneplans sounded fine except for a lute recording which tried to convinve me that lutes were 6 feet tall. The best sound, especially on the coral music, was a $900 Lansing system, rather beyond my budget. I ended up with a pair of Infinity 2000-II which came close to the sound of the $900 system, did well on all the segments on the tape, and cost $260 each. The only problem with the Infinity's is placement. Best results are obtained with placing them according to Carver's Holorgram suggestions, but this is impractical in my living room. BTW, I'd like to hear recommendations for a pair or fairly small speakers for my computer room wall. I don't want to give up the bass, but don't need terribly high audio levels. Listening is to FM and CD's with a Sony 20 watt receiver and 12 band equalizer. The 20 watts is adequate for reasonable listening levels, even with extreme low bass boost. The room is like: ------------------------- |s s | s = speaker | table table | | me w me = listening/hacking location | d | w | | | | | | door------------closet--- -- Chuck Forsberg WA7KGX ...!tektronix!reed!omen!caf CIS:70715,131 Omen Technology Inc 17505-V NW Sauvie Island Road Portland OR 97231 Voice: 503-621-3406 Modem: 503-621-3746 (Hit CR's for speed detect) Home of Professional-YAM, the most powerful COMM program for the IBM PC
rdp@teddy.UUCP (08/13/85)
[] In article <334@ttrdc.UUCP> kyl@ttrdc.UUCP (Kwing Y. Lee) writes: >Dick: > > When I first purchased the Klipsch speakers time and phase coherence were >just started to be the main design goals of speakers (Dalquist DQ10s). Back then >the criticisms that I heard about the Klipsches are that they are too big, too >expensive and they don't have the high end response that they should have.... >and also the so called "horn sound". Now nearly 10 years later, I still have not >outgrown by babies and I still think they sound fantastic. I would really >appreciated if you can summarized all the criticisms of Klipsch horn speaker >systems in one single comprehensive article. Thanks in advance. > > Kwing Ok, I will try. First of all, let me say that, as far a cabinetry goes, I cannot impune the manufacturers at all. The Klipsch K-horns ARE solidly built, well fitted, nicely finished, and, for something that large and awkward, are attractive in there own occasionally endearing way. And I cannot find a single chink in the armor of its progenitor, Paul Klipsch. However... The prime advantage to K-horns, and things of the horn genre is efficiency. If that is the prime criteria, then I can have no objections. Horns, realized in a practical manner, have real problems. First, the K-horn bass driver (as I can recall) is a fairly old style EV woofer, specifically designed for direct radiator use, albeit that alone does not acount for most of the problems. The bass enclosure, a severely folded horn, is, at best, a compromise. It is only a rough approximation of an exponential taper, and therefore cannot provide a continuous match along its path to the final load, the room. This causes problems such as internal reflections, cancellations, what have you. The sharp bends also cause reflection problems, as well as non-linear attenuations at the what might be considered only moderately high frequencies for a straight horn. At the the throat of the horn, measured particle velocities are high enough to cause non-linearities in propogation characteristics. Add also the fact that there is a many millisecond delay, which changes non-linearly with frequency. The net result is that the bass section has (as a measured fact) a very ragged frequency response, which has been shown by some researchers to level dependent. Mr. Klipsch continuously raises the spectre of "Doppler distortion" as the bugaboo of all direct radiator designs, yet all of the research papers I have been able to collect are, at best, confusingly undecided in total about either the existance or the detectability of such distortion. (H. D. Harwood, in the early 70's published an article which both philosophically and experimentally dealt a severe blow to Klipsch's assertions. I will try to resurect it if desired). Note also that because K-horns need the entire room to attempt to couple properly, they can be far more room dependent than direct radiator designs, judiciously placed. The mid-range and treble drivers are fairly mundane straight exponential horn designs, nothing great, nothing terribly bad. However, Klipsch makes the same, to me, very stupid mistake when it comes to orrientation. The best, most uniform and frequency-independent dispersion occurs at right angles to the long dimension of the horn. This means that in the Klipsch, where the long dimension is horizontal, the best dispersion pattern is vertical!. The measured dispersion characteristics of the speaker are truly dismal in the 1000 Hz and up regions of tghe spectrum. I will concede, however, the impracticality of re-orienting the drivers on such an already huge cabinet. The crossover is fairly simple-minded and straightforward, and that may, in fact, be it's saving grace! But.. Because of the tremendous phase and delay anomolies at the various crosover points, both the response characteristics and the dispersion characteristics at those frequencies are truly bizzarre! Since the indtroduction of more sophisticated measurement techniques, the measured characteristics of the speakers have been even stranger than even I would imagine. IMpulse response is very poor. The speaker has been measured with incredible long decay times, complex rise characetristics, and truly non-linear and non-minimal phase characteristics. Now, be that all as it may, SO WHAT, you say. I am also a musician of sorts (more a listener, though), as well as a reasonably accomplished instrument builder (I have built 11 harpsichords or clavichords, 2 small portative organ, one positive organ, and have repaired and restored many instruments ranging in age up to 300 years). Simply stated, music played on instruments that I am familiar with are reproduced very unfaithfully on Klipsh loudspeakers. Harpsichord music looses completely any hint of clarity, inner voices are completely muddled, and the higher registers are at once both very brittle and muddy. Organ music, recorded properly looses all of the "pipe noises" that can be easily heard in person and on other speakers of less technological pretention. Yes, K-horns certainly do play very loud, but so what? The kind of music I listen too, and the vast majority of classical music can be more accurately reproduced on lower effeiciency speakers of demonstrably higher fidelity. The efficiency and dynamic range arguments put forth by many horn proponents are not supportable, given the REAL requirements of reproducing music. The exception might be for rock, where sheer acoustic power is needed to replicate the effect of a "live" concert, but here we have no live analog to compare against anyway. Most proffesional PA systems are so much worse than K-horns or any other home speaker as to be laughable. (I once designed and built a set of high-power PA speakers for a rock band. They were VERY good. They were smooth, low distortion, wide bandwidth, etc. Nobody liked them.) Now, do I object to you liking your Klipsches. No, absolutely not. What I object to is their inability to faithfully reproduce musical sounds that I know well, in comparison to many other loudspeakers. I object to statements, such as one of the ones that followed your article, that "horn sound" is smooth, uncolored, low distortion. On an objective basis, K horns and most comercially available horns are neither smooth, uncolored or low distortion. At least two of those quantities can be measured objectively, and the horns fail both very miserably. I will concede that K-horns are probably the best, most practical commercial realization of a horn intended for home use. It's just that horn aren't very good. But then again, I like Harpsichord music by Francois Couperin, so I must be nuts anyway. Regards.. Dick Pierce
george@sysvis (08/20/85)
[...] > ... Horns, realized in a practical manner, have real problems. > ... they can be far more room dependent than direct radiator designs, > judiciously placed. > ... What I object to is their inability to faithfully reproduce musical > sounds that I know well, in comparison to many other loudspeakers. I object > to statements, such as one of the ones that followed your article, that > "horn sound" is smooth, uncolored, low distortion. On an objective basis, > K horns and most commercially available horns are neither smooth, uncolored > or low distortion. At least two of those quantities can be measured > objectively, and the horns fail both very miserably. > Dick Pierce I would be interested in hearing your arguments FOR any specific direct radiators that are acceptably "uncolored" and which don't require a one megawatt amplifier to drive them. Also, what is "judiciously placed?"
rdp@teddy.UUCP (08/29/85)
In article <-1460374@sysvis> george@sysvis writes: > >[...] > >> ... Horns, realized in a practical manner, have real problems. >> ... they can be far more room dependent than direct radiator designs, >> judiciously placed. >> ... What I object to is their inability to faithfully reproduce musical >> sounds that I know well, in comparison to many other loudspeakers. I object >> to statements, such as one of the ones that followed your article, that >> "horn sound" is smooth, uncolored, low distortion. On an objective basis, >> K horns and most commercially available horns are neither smooth, uncolored >> or low distortion. At least two of those quantities can be measured >> objectively, and the horns fail both very miserably. >> Dick Pierce > >I would be interested in hearing your arguments FOR any specific direct >radiators that are acceptably "uncolored" and which don't require a one >megawatt amplifier to drive them. Somehow, I think the author of this statement is posing a very leading question, and I get the feeling that now matter how good my answer, I am doomed to failure. My system at home uses "direct radiator" loudspeakers, and I have a measely 75 watts per channel to drive them. I have never seen nor heard the need for 1 megawatt, nor 1 kilowatt for that matter trying to reproduce the levels that I enjoy. My musical preferences are baroque keyboard music, including organ (I have measured SPL's of REAL pipe organs, they are NOT very loud). At one point, when such information was of inportance to me, I actually measured power output using a high speed analog to digital converter and a rather large array of analysis programs. For such things as the kinds of music I listen two, the amplifier was screaming away at a blistering 3 watts on LOUD passages. For my needs, th argument that direct radiator loudspeakers require megawatt amplifiers is a crock. AS to the arguments for direct radiator loudspeakers, this is a whole can of worms in and of itself. At some point I may enter in to the discussion, but time eludes me now. I may prepare some sort of paper over the next few weeks. But to me, the best argument for a given type versus another is that it nore faithfully reproduces the musical experience I am familiar with listening to live music. Comercially available horns, in this respect, fail. Period. Direct radiators, frankly, fail also, but nowhere near as badly. (A note here. As far as I am concerned, I have yet to hear any system which even loosely sounds like live music. The current technology isn't even close. But one can still make the choice between merely bad and positively dreadful.) > Also, what is "judiciously placed?" Judiciously placed, in the case of K-horns, means that they must be placed along the shorter wall of a large room, the corners must be smooth straight and very solid, and, ideally, the room must be of such proportions as to continue properly the taper of the horn. Note that since the speakers, because of the horn, couple so effectively to the room, they are, therfore, extremely sensitive to room loading, much more so than direct radiators. I would sincerely like to avoid a loudspeaker technology pissing contest, as it is unproductive (No, I am not accusing anybody of starting one!). If you like horns, fine. If you don't, fine. If you don't like me not liking horns, tough. But please let's avoid the hyperbole like "megawatt amplifiers". It is completely baseless in the real world, and really doesn't inspire informed responses. With apologies for the minor flame, Dick Pierce