who here likes DEEP BASS?

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would you tell me frequency you tuned this bass-reflex? [IOW where it rolls-off in the bass] also, is the second speaker pic a transmission line? how low does it go? is the 3rd speaker a lowther? i know, i'm just full of questions.

click on me to hear CBC host Carol Off speak in her distinctive contralto

if you sound like this person [in the above link], then you are safely a contralto. it is safe to say you probably sound something like this person, or perhaps a bit higher like singer carly simon when she is speaking in her distinctive low smooth rasp. as for sounding like men, i know your voice has to be higher-pitched than actor john goodman, who is a bass-baritone but i have heard women who spoke so sepulchraly also.
in anycase, i'd love to hear you speak. i have always liked listening to deep-voiced women.

The jackhammer (big square bastard) is an 11 cubic foot enclosure and the vent is tuned for 32hz, actually above the driver's 19hz fs (moving mass is almost 3 lbs on that machine) - surprisingly enough it nets a pleasant, if somewhat inaccurate +5dB bump spanning that range and leveling as you go up through about 700hz, where it's just not possible for most amplifiers short of a 4kW crown to control the cone any higher than that. BTW this particular enclosure/driver were assembled specifically for the engineering dept at atlas sound (also part of the same company as MTX) to torture test their commercial amplifiers, so it has a unique (very floppy) spider geometry and the outer surround is made of the same aerated neoprene as our TS85 drivers, while the "normal" jackhammers use a proprietary, but somewhat stiffer material. at 100hz efficiency is 102dB @ 2.83v/1m wired for 4 ohms. It's very cool, listening to something with that much meat.


The fishnet/red towers are low velocity ported, made from discarded parts and pieces as a weeknight project for a friend. I did a careful job of them, but there is nothing particularly exotic... just a lot of hours listening to Takenobu and Blue Man Group and marching percussion recordings through them and relentlessly tweaking until they met my approval. I have less than $30 in them, in stuff like fishnet fabric and paint and glue. The rest is scrap parts pulled from other things (the port is made of leftover ABS poop pipe from my bathroom remodel and the crossovers are parts from other crossovers, plus a pair of hand wound inductors made from an unwound e core xformer) - port freq is tuned at 29hz and they go -3dB at 37hz, measured in the anechoic at work, my goal was for them to cover at least a low E naturally without need for a sub, so I'm happy. Very pleasant speakers to listen, i love their personality and sometimes almost regret that i gave them away, but Tim loves them and I love making friends happy.

The steampunk ones are more fun, compound ported ("hidden chamber" as some call it) with a golden ratio expanding mouth at both ends of the outer port, floor loaded, and again made almost entirely from discarded junk. I made them for another friend, using JSD Audio ceiling speakers (it's a low cost badgeneering company in california) and some funky tricks to give them personality - for example i put all of the crossover inductors within the magnetic flux of the voice coils, so they influence each other and create a subtle harmony that makes the sound stage miles wide without reducing intelligibility much. I really had fun making them and Jojo seems to love owning them, so it's a win win there. Measured response is dead level down to 51hz and then drops at the expected "sealed" rate of 12dB/octave to a second plateau -5dB below that, remaining dead level again to 29hz where a second 12 dB/octave roll off occurs. If I had these to do again, I might use a beefier driver and try to just aim for a more smooth, single stage roll off on the bottom but they still are quite enjoyable. Definitely not dance party speakers, but for any casual listening there's absolutely no want for a subwoofer.


Anyway sorry if I was too verbose here, it's my favorite (g rated) hobby so I enjoy building, designing, and talking about it

cheers.

decware describes plans for a monster subwoofer called the imperial which is the size of a refrigerator and claims to put out 25 cycles per second loud enough to "slosh the liquid out of the glasses on all the tables in a large nightclub." i was wondering if it was possible to tune your big square illegitimate child to a rock-solid 8 cycles per second, so it could reproduce the 64' pipes on the largest pipe organ in new york city [or double 32' pipes beating together for resultant 64']



is this the same effect as a comb-filter? that is fascinating, can you tell me how wide their [stereo imaging] sweet spot is?



thank you for your informative reply. i don't often get to talk to a tech genius regarding audio or much of anything else.

The retail version of that woofer has just under 500 square inches and displaces about 18 cubic feet of air at xmax (not xmech, which is another 19mm past xmax) , with enough motor to efficiently turn 4kW into audio before efficiency rolls off (voice coil and magnet curie temp. reduce efficiency somewhat past 4kW continuous rms, but efficiency is fairly linear up to there when operated <150 degrees F) - and it's a good sounding machine surprisingly enough. We don't sell many of them, because they are cost prohibitive and a few peoples' awful installs in cars have soured the market due to bad press - but they actually are very musical and the round 22" version of them is an exceptionally good sounding machine. They aren't just a big motor borrowed from one of our 15" drivers (like cadence, audiobahn, etc have done to make unusually large drivers) - the boss dumped several million into developing them and they represent some very good engineers' best capabilities. The head engineers were Brad Deitritch and Dan Roemer, whose Xtant subwoofers and DCM Timeframe/TFE series are well respected.

Sorry if the above sounds defensive, I've grown accustomed to "heading off" negativity that seems to follow the large MTX subwoofers around, not just because of company pride but because it really is a properly engineered machine and any unpleasant sounding applications of it are almost definitely the fault of the installer simply not knowing how to work with such a nonstandard driver.

All that said, yes in a 1/4 wave horn, a TL, or a very deeply tuned enclosure one would have no trouble reproducing a 64 foot fundamental at very satisfying SPL. You can roughly equate the output and characteristics of the 22" round Jackhammer to 10 or 12 of the "meanest" 12" subwoofers you can think of, but without group delay other than that which you might introduce with a port. If cost were no object I would definitely have a pair of these firing on-axis in my listening room, albeit I would need a somewhat larger room than I have now





It's not quite a comb filter effect, in fact I'd find it hard to describe exactly what the resulting sound is. Effectively it's decaying feedback that continually occurs at 90 degrees off phase, the inductor and the voice coil (which is also an inductor of course) affect each other continually which I can only visualize in my mind as creating a really "lumpy" but coherent wave front - resulting in the wave front becoming more planar and less point-sourced. It definitely costs SPL but doesn't appear to cost clarity or intelligibility. Higher frequencies tend to be affected somewhat more, though in the tweeter on this application I chose to go first order with the crossover (at 7300hz) and used an inductive resistor directly across the tweeter itself to pad it down, and gain this effect.

The whole of it isn't magic and should not be applied to every speaker but because true perfection (i.e. the listener's perception that he or she is directly hearing a live human singing, a live cello playing 10 feet away) is as impossible as pinpointing the world's one most beautiful woman, I like to add "flavor" to individual pairs of loudspeakers. I know this idea might be abhorrent to many audiophiles, and I understand why - but my preference is to put "beauty marks" on imperfect machines so they are more memorable, without removing the beauty

*edit - I forgot to address your query about the width of the soundstage - that's something I'm not sure I can answer directly as our anechoic chamber at work is too small to do any stereo listening in, it's suited for single device measurement with instruments only. At home, I have a listening room but it wears untreated boundaries at 18ft and a slanted ceiling - however it is worth saying that on a 6ft couch in that room there is no particular position that is better or worse than any other, and in the new home of their owner (the guy I gave 'em to) it's really quite pleasant to sit on a sideways couch, entirely to the left of both speakers and still pick up a defined left/right image with clear dialog centered on screen, not on whatever speaker's closest.

heh... I find that hard to believe, this place seems crawling with very well informed folks I'm self taught in audio, it's a fun hobby that accidentally turned into a career - hardly genius but I'm always happy to chat about sound and the machines which reproduce it .

You seem to have a good understanding of audio yourself, do you have any cool projects or systems to share?

Last edited by apanthropy on 09 Jun 2010, 8:20 pm, edited 1 time in total.

I forgot to mention, I'm fairly well familiar with DECware's goodies, definitely like them and I like how Steve has managed to design very friendly-to-use bandpass alignments. He seems to understand quite well that there is nothing inherently bad sounding about bandpass, just the way many ill-informed users apply them. Way cool stuff!!

Also Danley uses many of our drivers in proprietary ways, have you seen the Danley Matterhorn? It uses 40 of our 15" automotive 9500 series subwoofers in a tapped horn configuration occupying a 20 foot shipping container, along with one 1kW amplifier per driver. I know of no more powerful individual subwoofer on the planet, it's a really neat machine. The only opportunity I ever had to hear it was at the last NSCA trade show, definitely love at first sight

how much power does this monster require to achieve 8 cycles per second/110+ dbl spl@1m? i used to own a carver amazing subwoofer but my old house was not wired to handle the amperage that thing would suck out of the wall. when the organ music played it would make the lights dim throughout the house. it produced usable small room output at 16 cycles per second, amazing for an 11 inch-per-side cube. any future sub i ever am able to get MUST use substantially less juice than the carver unit did.



sounds like treble stereo chorusing to me. does a critical listener to that design ever hear phlanging? or is it largely inaudible due to the higher treble concentration of the enhanced stereo effect? in any case, i SURE would like to hear it somehow. i wonder if this speaker sound effect can be recorded anechoically so that it can be heard on another sound system? i wonder how it would make my pipe organ recordings sound?



lots of experts don't like chatting with average schmoes, only with equally gifted and in-the-loop folk like themselves, so you are a refreshing change with a populist attitude towards knowledge.



i just read a lot about it- i've subscribed to the AUDIO and HIGH FIDELITY mags [i sure miss 'em ] since i was a schoolkid. whatever you may think about the late julian hirsch, he made audio analysis real for me. btw, i find Stereophile's audio reviews totally useless for me, as they are too artsyfartsy and/or too technical, with no middle ground.
anyways, i am totally non-talented in technical matters, i am strictly an "end user" and not any kind of creator of intellectual [or any other kind of] product. but i am a deep bass freak, i just love the aural tactile massage that a good loud 8 or 16 cycle per second fundamental does to my body and eardrums. deep bass just makes me feel good. i love high-fidelity audio, stereo or surround sound. one of my fondest memories is listening to a pair of magnaplanar [or is it magnapan?] tympany IV panel speakers, while they were reproducing an phonograph recording of a bach pipe organ piece [can't remember which one]- it was like i was in the recording venue itself, except for the surface noise which curiously seemed to float in an aural cloud in between the listener [me] and the speakers. most magnapans force you to hold your head in a virtual vice in order to hear the fantastic stereo spread effect they are capable of reproducing, but the tympanis let you walk around in front of them without losing the imaging. amazing. my favorite speaker of all time. but horribly inefficient. but i digress.
the only projects which i can say i have accomplished on a steady basis, are digital audio restoration using a variety of hardware and software programs. audio restoration is more an art than a science. it takes a discerning ear and revealing electronics to do it justice. i have heard many bad or mediocre examples of it. i try to do much better, at least for my own backlog of corrupted recordings. i would love to get involved in video restoration but am so far out of the loop of things [i don't live anywhere near a big city or media center] that it is not possible.

sorry it took a bit of time to get back to you, I'm at a trade show right now and kept fairly busy.

To achieve 8hz at 110+ dB will depend on the enclosure. A single 24" subwoofer in a boring ol' ported enclosure, say around 34 cubic feet with about 280 square inches of port cross section about 210 inches deep (there are many different ways you could tune it, this is just my first shotgun at it) should put you around 110dB at 8hz with a little under 180 watts. This is not a typo, remember because the machine has so much surface area on one motor you're only fighting the mechanical losses of one spider, one surround, one set of gap imperfections, etc. and also remember it's got a 1/2" thick top plate, there's a lot of magnet in that gap. With this arrangement you should be able to operate the machine continually (sustained 24 hours a day, sine wave) at around 133dB continually at 8hz with around 4kW of very good, completely unclipped power. Remember that if you clip even 1% you approach thermal runaway quickly so you would need to either fan cool the driver, sink it *hard*, or give it cleaner power.

If you get a little more exotic with enclosure, for example back chamber a 300 square inch port at 10hz and give it a hundred square feet of mouth on a 30 foot horn, sustaining 8hz should be possible at 110dB with less than 100 watts but your maximum rms handling goes down a bit because of how heavy the horn full of air is. You would run into cooling problems above 2500 watts or so (educated guess) because pushing a hornload of air is like the loudspeaker equivalent of towing a trailer up hill. Obviously peaks could exceed that, we've sent a dynamic 16kW through these things a number of times and while it cooks off some of the voice coil glue, it only does that once or twice and then tolerates as much as we have amplifiers to give it.

As an aside note, it should be easy for you to reach your objective of 110dB at 8hz with a dramatically less costly sub, honestly any high quality, high SPL, high BL (think: premium automotive type) 12" sub can hit that target without breaking a sweat in the right horn. If called upon to do so, I could probably sustain that target with a $30 8" driver but you wouldn't like the size of the cabinet As they say, "loud, low, and small. Pick 2"

Those compact subs like the carver and sunfires, they use a neat property by which the low end roll-off of a tight enclosure is a predictable 12dB/octave below the systemic FS, so by choosing a very high FS, extremely high power handling driver you can simply apply a +12dB/octave filter to the signal and result in level response. The sound is brilliant, but for every 3dB you add it takes 2x as much power... so for every octave you drop you need 16x as much power to compensate. You can see how that can get ugly very fast




I doubt it's possible to exactly capture the sound in a recording... it affects the actual shape of the wavefront leaving the loudspeaker which would definitely affect the recording and might sound kinda cool - but likely wouldn't be reproducible. I wonder now, how that might sound looped.... played back through the same speakers, recorded, played back through them, recorded a couple times to layer the recordable artifacts along with the electrokinetic effects.. I bet intelligibility would fly right out the window but for a single instrument layer could sound psychedelic!! To me, playing with sound is more fun than merely trying to pass it undisturbed - as long as clarity and a sense of the original artistry are handled well and you never "see the paintbrush" as they say. Hiding the paintbrush is the hardest part to do well... and the part I have the most fun with




The whole system of machinery to record, carry, and reproduce sound is a fascinating one, and if you were not blessed with the coordination or self confidence needed to produce music, there is always fun to be had in reproducing it. For my part, I think of the reproduction apparatus as much like a musical instrument as the objects in the musicians' hands, and I'm thankful for all the artists out there making music worth recording, worth playing back again and again. The audiophile crowd mostly annoys me, so many of them attribute magical properties and voodoo to what truly is just machinery - and lots of them seem to delude themselves into thinking that there is even such a thing as perfection, an awful lie to tell ones' self - and then go about comparing everything they hear to a bogus and inherently stupid ideal. My job takes me to audiophile shows, and as much fun it is to see other engineers' designs doing their work - sometimes I'd rather drive a deck screw through my temple than hang out with the "MY WIRES COST 3000 DOLLARS!" crowd. Beyond mechanical durability and linear resistance, the only thing money buys in wire is pride of ownership, pure and simple.

heh.. another "book" - ah well think of it as a magazine article eh?

hoffman's iron law still in effect, i see.



i did that, 3 roll yer own CDs worth. i took a CD, played it through a Hughes Sound Retriver, then from that into a carver sonic holography box, then input it into a model 88 kloss table radio with a neat stereo wide thingie, then digitized the output and fixed the resultant phase problems on my puter using SoundForge, then made CDs out of it. i found though, that the CDs are at their best played back through the model 88 kloss table radio set to "stereo wide" yet again, which gives the listener a mind-blowing aural cloud effect, with an effective listening area "sweet spot" about 3 head-widths wide laterally with a 3' high height window. the effect is like you made a magical alternate reality aural zone that you can stick your head in and just your head is in the original recording venue, until you pull your head out of the zone. i hope that made sense.



i'm glad that on this forum there aren't many subjective versus objective arguments. i've noticed that many "audiophiles" tend to get hot and bothered about their expensive wires and such. such haut tribalism is not my cup of tea. i never claimed to have golden ears but i do know what i like to hear and what i don't like, and that suits me. i've never been able to hear the difference between wires and amps with the exception of single ended triodes which to me sound soft and sweet. and i've noticed that the trebles on upsampled CDs have the same soft and sweet trebles. but it could just be my fertile imagination.

there was a string bass player by the name of major "mule" hollis, who was known for being able to hum and scat in a deep bass voice, down along in unison with the notes he bowed on his string bass. a really weird yet cool effect that made frank sinatra laugh out loud.

BOOM-BOOM BOOM-BOOM *takes phones off* what u said?

I love the feeling of my guts being scrambled!

I've got my car wrapped in JL Audio - components, 2 x 10W3V2's, not the most powerful set up but I get my dosage. For me though, while I'd say that I like deep base it has to be balanced out - ie. if its dominating the highs and mids its too much. On the other hand I have a couple tunes that end up in rotation where, you'd have to turn the amp pretty low.

Here's a guy who's been getting a lot of acclaim for his low frequency work (Breakage), this one hits noticeably louder in my car than a lot of things at the same amp level:
[youtube]http://www.youtube.com/watch?v=71saGC8juwU[/youtube]

i just read that wild grouse and elephants have one thing in common, and that is they use infrasonic [extremely low frequencies below human hearing] to communicate long distances with. interesting. i heard a recording of both of 'em doing this and it is a fascinating sound, almost hypnotic. the elephants basso profundo rumblings are especially pleasant to the ear.

i love the deep bass of military ordnance- cannons, antitank weapons and the like. i made a CD of cannon shots, space shuttle rumbles, trains and such. i also love the deep, reverberating BOOOOMM!! !s of the fireworks up close. [but the home-user fireworks-stand fireworks just make irritating pops, cracks and bangs.] i'd love to be able to experience the fourth of jul-Ivers events up in seattle, the fireworks on the waterfront and all that.

for deep-bass lovers who are short of fundage [just like me ] but still want to hear the low-C organ pipes and concert bass drum BOOUUMMMMs and such, one free way to enhance and deepen the bass experience from your stereo of modest quality, is to take your full-range stereo speakers [NOT satellites] and put them in each corner, then put your listening chair against the back wall opposite the side of the room where the speakers are cornered, then turn up the 30hz slider on an EQ if you have one, or minus that, then turn up the bass tone control on your receiver which generally applies more of a boost lower down in the bass than up higher, a sort-of passive deep bass boost in all. i used to do this in order to hear and feel the 16' pipes on my old pipe organ records. when i was able to get a modest subwoofer, i put it in a corner and did the same thing and was able to actually discern the 32' organ pipes, which are unmistakeable with their flapping growling "count-the-cycles" bass.