formica

If i recall, Klipsch's Pro Heresys are actually a ported design in about the same size cabinet... but then they don't use the same woofer either.

That is correct doug... it is very dependant on the soundcards DAC, many of which are quite cheap (mine). It is also relatively slow (1X) because it's an analog input. Presently it's the same proceedure as burning CD copies of your vinyl records to carry in the car with you. If it's a multichannel recording, you'll have to set your player on stereo playback to make sure nothing is lost. Another option that preserves the full quality would be to exchange disks on a regular basis. What's the chance that you will both listen to the same recording during the same week? Rob

Lots of good info and definitions you can check it out at: http://www.diysubwoofers.org/define.htm Here is a quote from that page: Qes = Electrical Q of the driver at Fs. Qes is a measure of the driver's tendency to resonate at Fs, based on its electrical characteristics, e.g. magnet strength, magnetic circuit characteristics, etc.). The driver's overall resonance characteristics are usually dominated by Qes. Qms = Mechanical Q of the driver at Fs. Qms is a measure of the driver's tendency to resonate at Fs, based on its mechanical characteristics, e.g. surround compliance, the compliance of the spider, weight of the cone, etc.

I stand corrected... you are right about overpowering them. I didn't run them on a simulator and so i forgot to factor in the box size(very large ) Correct me if i'm wrong, but with 1000W they shouldn't bottom out till below 16Hz and 1250W (315W each) would get below 18Hz ? I guess it depends on how low you want to go...

You have your subwoofers in an apartment ?! Even a concrete structure has a good share of acoustic weak points (I know from designing / building them)... I can't imagine what the neighbours think of you ! 1) First step, buy your self the ultimate music room accessory... a detached home... 2) Then I'd follow Dustin's recommendations, probably with 4 AV15's in an IB and 2000W @ 3000W of power... should get you dangerously loud and flat. IB are theoretically great... even Thomas Nousaine (the sub man) uses one.

Actually, i should have been a little clearer on which "sounds" were affected... and how they would change the overall character of the room. I hate to tell you, but your room is already altering the sound of your speakers... wall treatement helps control it. Speakers are usually rate for their frequency range given a certain variance in loudness (eg: 35Hz to 20kHz ±3db) which were measured in an anechoic chamber. Speakers cannot achieve this ideal in the real world due to room interactions even if the speaker itself had a perfectly flat response. An anechoic chamber takes the room out of the equation to test the speaker itself. Basically we are talking about resonant frequencies and echo. You walk into a church with it's hard surfaces and very little absorption material and you get a lot of echo over the whole frequency band... and is not really the way you want to listen to movies or music. Walk into your local theatre, and it's a totally different story with its ceiling, walls, and floor treatments. Another example would be a new home before you move any furniture in... with little material to absorb reflections, it sounds like a big empty box, annoying even to talk to one another. You then install the drapes, bring in the sofa, etc... and all of a sudden things start to calm down. The direct radiating sound will not be affected by the sound damping, but the reflections will, so in a sense the speakers will perform closer to their specs. Two other items I mentioned in my previous post that I'd like to clarify. Low Frequencies: I mentioned that the wall treatment wouldn't attenuate these frequencies much, and this is because their long wave lengths they would require very thick insulation. Measure any room, and you will see that it's got some pretty important resonances in this region. If you want flat, you got to EQ your sub and/or add bass traps, otherwise lower the resonant frequency can help by flatting your speakers response. Example, you have Belles which roll off (-3db) around 45Hz and your room resonance is at 55Hz... your room response will have a large peak right before it rolls off. Lots of kick but no rumble. Lower the resonant frequency to 30Hz, and all of a sudden as your Belles become less efficient (45Hz) the room comes in and helps boost it back up. This is obviously an ideal situation, but nothing is really that perfect in practice.... Primary reflections: There are a couple of excellent white papers at Harmon by Floyd which goes into great detail on how the primary reflections affect the overall sound of a speaker. In a generalized summary, what you hear at the seating position is the sum of the direct sound and primary reflection. Remember that a speaker is rated in an anechoic chamber without and reflections. This is one of the places where specs can be really deceiving as it may not have an even dispersion pattern over all frequencies, therefore certain frequencies will get boosted more than others by these primary reflections. That is why you will often see acousticians place sound absorbing material on the side walls near the main speakers. I believe the THX spec requires horn loaded speakers to be used just for this reason... as the horn can control the dispersions pattern quite accurately, and primary reflections can be kept to a minimum. An advantage most Klipsch speakers have, which isn't often measured in an anechoic chamber. All this said, I'm personally set up in a asymmetrical room with little treatment and a 10db resonant frequency at around 40Hz... Moon, want to trade rooms with me?

All you would need to turn them into acoustical panels would be some semi-rigid fibreglass insulation (like the old Glasclad panels, or the yellow stuff they use in the vinyl-covered acoustic ceiling tile) and a more porous material. I'm also quite confident that they would partially function even if the fabric isn't entirely transparent, but I'm just not sure of the extent. My guess you'd mostly lose out on high frequency attenuation. I like the sketch... kinda what I figured you were aiming for minus the insulation.

---------------- On 4/22/2003 10:55:18 PM TheEAR wrote: Answer GET AN EQ ---------------- Yup... for a SUB, that was what i was hinting at. I have a Behringer BFD on my short list. I have to build the sub first though ! Along the same idea, I'm curious how the new velo with built in EQ's perform Rob.

I guess it depends on what you are trying to accomplish with your panels. I think your panels will do several things: - they will deaden the sound in your room to some extent, whether or not they are acoustically transperent. When i say "deaden" the sound i'm talking about the reduction of standing waves, similar to the effect of adding a carpet to the room. The frequencies they will affect will be dictated by the fabric and the insulation placed behind, but don't expect much effect below the midrange. It does produce a "quieter" feeling to the room... but to much damping can make a room sound dead. - the panels placed on the side walls near the speakers will reduce the primary reflections. Since your speakers are horn loaded, it's effects won't be as dramatic as those which have a wide dispersion (dome tweeters). That is why some speakers sound so different when placed near a wall, as the the sound reaching you is the sum of the direct and reflected sounds. Again, this will affect mostly the high frequencies. - the panels will also make the room seem larger from an acoustical point of view, esp when considering the low frequencies. If i'm not mistaken (feel free to correct me if i'm wrong) increasing the rooms dimensions should lower the primary resonant frequency of the room... I'm sure i'll think of some others points... but all-in-all i do think it's a nice idea. Rob

The current trend seems to be: - filling with polyfill for sealed subwoofer (the kinda you find sold as stuffing at walmart) - lining the inside walls for a vented enclosure with either egg-crate foam or polyfill but not filling/stuffing the box I don't think either will cause a fire hazard as the hot elements of the sub amps are oriented towards the exterior for cooling.

I think i know which one you are speaking of... i saw it on an italian site... http://www.royaldevice.com/custom3.htm I thought i'd post a couple of the specs on this beast: * SUBWOOFER horns are built underneath the floor in a cavity of 1 meter deep. Each horn is driven by 8 x 18" (47 cm) woofers. A total of 16 woofers. * Each horn is 9.5 meters long and has a floor mouth area of 2.2 square meters and reproduce starting from 10 Hertz FULL POWER. The real mouth area IS NOT the one on the floor. The real mouth have to be considered together with the side vertical frontal panel. The total horn is calculated onto the listening point considering the side walls and the ceiling loadings. This reduces the floor mouth that is not in open air. * Total efficiency: more than 110 dB/1 watt/1 meter

Remember that halfing of the power (350W / 2 = 175W) will give you a 3db drop in the overall volume... not a huge difference. A guestimate for your 100W amp would be around 5db drop... If you buy a passive sub, there are a couple of things you should verify: 1) note the rated resistance of the sub.... (4ohms? 8ohms? or dual voice coils giving different resistances ) 2) note into how many ohms the amplifier power is rated... (some amps won't handle 4ohms while other will put out as much as double the power into 4ohms versus 8ohms)

Who's on first?

double post ...

---------------- On 4/22/2003 2:49:22 PM jstanton8 wrote: To see if there's an unwanted low-pass filter on the amp maybe I should feed the bastard some test tones from 30 Hz on down and see what happens. ---------------- I think you've got a good idea... Try: 1) full-range line level output and drive it with a series of test-tones, see where it cuts off 2) LFE out-put with the same series of test-tones see where it cuts off both upper end and lower end

jstanton8: Which Pro amp do you have? Just wondering if it's not a combination of a couple of things. It's not uncommon for pro-amps to have built in low-pass filters which may rolloff anything below 20Hz ... and if you combine that with a LFE set at a relatively low crossover point, and a slightly less sensitive line-level input on the amp... might all combine to give a pretty low output. You can try playing with the settings on your receiver, increase the x-over point, and increase the subwoofer level... see what it gives you. Also give your amps specs a look over.

---------------- On 4/21/2003 7:23:59 PM fabulousfrankie wrote: The room, the positions of the listening position and position of the subwoofer, the lowpass and highpass XOs used for both the subwoofer and the rest of the speakers , the phasing of the subwoofer relative to the rest of the speakers, and the calibration of the subwoofer. ---------------- This is very true... it's not unusual to have room resonaces in the 10db range! So you "flat" sub may sound boomy in one room and musical in the next.

I'm guessing you were already looking at the http://www.prosoundweb.com/lsp/ Horn Subwoofer designed by Danley using the LAB12 driver (available at PartsExpress)? It appears to be a good design, and like you already mentioned the biggest drawback of horn-loaded subs is their inherent lack of bass extension and their complex construction... while their biggest benefit is efficiency. They are also HUGE for interior use... and you thought a heritage Klipsch is large... Are you looking for high SPL or to use a low powered amp? Depending what your maximum SPL/amp you are looking for, you may consider the Adire Audio Maelstrom 18" driver in a standard enclosure... http://www.adireaudio.com/diy_audio/drivers/adire/maelstrom.htm I know you are thinking that this thing is large, but it is very efficient with a powerful motor, moves a lot of air and uses a small enclosure. Plug in it's specs in a program like WinISD and you'll see that it's got a very short group delay (often referred to as a fast sub or a musical sub). Another option would be, as the current trend seems to be, to get a sub with a large Vd (volume displacement) and buy a pro amp to go with it. In this group you would find subs like the Stryke AV12 and AV15, Adire Tumult etc... I had posted about the JBL MPC amps on liquidation on here a while back... at 192$ for 900W and 143$ for 700W power can be cheap... but they do require converting from 230V to 120V. I've opted for a JBL-MPC 700W with the Stryke AV15 to hopefully keep up with my Klipsch.

I remember reading an article about unbraced subs and the required "wall" thickness in order to do it somewhere online... unfortunately I don't have the link handy. Given the woofers displacement volume, the rigidity of the material used, and the maximum size of an unbraced length panel, you can calculate the required thickness to prevent the cabinet from resonating in the audible range. If I recall the general rule of thumbs for an average sub were along the line of ±10" to 12" unbraced dimension for ¾" MDF ... If using the bracing is impossible and you go with 18" I'd consider doubling your outside enclosure walls to 1-1/2" MDF.

I agree that both formats have potential; it's just a question of time before some respectable recordings begin to come out in reasonable numbers. I was recently discussing this on another site... The way i see it, as music fans we try to buy the equipment to best reproduce the music we love, and hopefully reflect the recording engineers intention. Unfortunately, their intention doesnt always sound good... I find it hard to believe the inconsistencies still found in modern recordings, especially now when the technology has become so inexpensive and readily available. Is it possible that the record companies aren't overly promoting the formats simply because it is much more revealing to sloppy work? Similarly, Heritage speakers are often criticized for being to revealing... but speakers shouldn't be there to hide the recording glitches either. Rob

I might be mistaken but aren't DTS recordings at a lower sampling rate than regular CD's? Whell, if you really want to experience high-resolution surround sound, you should try to give some DVDA or SACD's a listen... they do sound quite a bit better, even to my "non-golden" ears. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> When setting up your system, adjusting your front and rear channels with a SPL meter is an important step in keeping to music where it belongs. I also found that when using matching fronts and rears, the overall balance is very pleasant.

A word of caution, as many of you know, every 3db boost in volume is a doubling of power... So assuming your 1000W sub is fed a std Pink Noise signal and you have a 9db boost at 20Hz, the sub will reach it's max with only about125W being fed to the non-boosted frequencies!!! (I realize there are other factors such as % of musical content in the boosted frequencies versus total content... but it's just a close simplification) A parametric EQ can help performance more by reducing any frequency which is being "amplified" by room resonances... therefore giving you sub a flatter response. This will improve its lower frequency response even if it at first seems counter-intuitive. Let me give you an example... lets say your room has a natural 10db peak at 45Hz. When you adjust your subs level (measured or by ear) it'll seem to be at the same volume as your mains when the 45Hz peak is slightly louder than main speakers... lets say 4db louder. This will leave the rest of the subs response 6db lower than your mains... If you cut the 45Hz peak down, you will be able to raise the volume of the sub without drowning out your mains. Remember though, a 45Hz peak can add a lot of kick to your music and it could take some getting used to if you cut it down to a flatter response. Hope it can be of some help... Rob PS: I'm not sure about the AC3 version of NIN DVD, but my DTS version has a lot of mid-bass but very little low-bass (several songs only)...

---------------- On 4/17/2003 11:27:18 PM SCOOTERDOG wrote: Like any format some of the disc's I have bought were not totally impressive. It really depends on the original source tape, engineer etc. ---------------- I couldn't agree more!! Both formats can be great, and i guess you "don't shoot the messanger if you don't like the message" If you are not up for a "combo" player, i'd go with the format which has the most music you like available. I have DVDA and agree that the detail and soundstage really good on a properly engineered disks... but unfortunately given my taste in music, I find the quantity of disks lacking (SACD is equally poor in my case). Honestly i can't wait till more music is made available for either format... Rob. PS: Scooterdog, 40 disks? did you buy them all??

I have both as well... but models from very different price points. I have A/B both the Heresy and Paradigm Phantoms at even used them in the same HT for awhile. In a very summarized way, the biggest differences would be (very obvious with pink noise): -Phantoms Good: Low cost, good low frequency extension smoothly integrated into the mid-range... -Phantoms Bad: lack of upper midrange and muted high frequency, lack of power handling (these are a base model after all), a little dull -Heresy Good: Lots of mid-bass kick, great mid-range definition, good high-frequency performance, great power handling -Heresy Bad: Expensive, lack of bass extension, a little bright I have never compared my Cornwalls directly to the Phantoms, but they definitely have the bass extension that the Heresys didn't. (I'd even say they sound a little boomy in my room, but I have a resonant room peak around 45Hz). I have also heard the Paradigm Studio series in the store, and they corrected several of the Phantoms shortcomings in the dynamics of the mid-to-high range frequencies. I would describe them honest and flat. Personally I like my Klipsch as they are exciting and lively.... and having owned Heritage speakers for over a dozen years, I don't find them tiring as some other forum posters sometimes describe them. Like I said, the comparison in my case may not really be fair considering the price differences. Rob

I did a quick search and "William F. Gil McDermott", who is quite knowledgeable, actually posted about it on these forums... he stated: "For reasons which I don't understand, speaker drivers made with Alnico magnets do not create very strong fringe fields. Perhaps it has to do with the magnetic conductive structures which direct the field to the "gap" in which the voice coil sits. These are the pole pieces. Older Heresy use Alnico magnets. Therefore, you may not have quite the problem anticipated." You could read the whole thread : http://forums.klipsch.com/idealbb/view.asp?topicID=30658&forumID=69&catID=19&search=1&searchstring=&sessionID={83259FB8-5692-430F-9305-5EA7F8663166} hopefully that link will work... Rob