Design a subwoofer for headphones
Apr 22, 2002 at 5:51 AM Thread Starter Post #1 of 28

Jeff Guidry

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Most of us use headphones as a comprimise because we can either not afford a full sized system, or we don't have the space for one. Also, it's difficult to listen to music at satisfying levels without disturbing the neighbors, roommates or significant others (if you're bisexual, would it be significant eithers?).

What if volume were not the prime consideration? If you simply prefer the overall intimacy and detail the headphones give, or you are simply pressed for space, what's one of the main things that's missing from a headphone system that you get with a full sized system (besides soundstage)?

That's right, bass! Most headphones either reproduce bass accurately (and without much impact) or emphasize the midbass for a more satisfying slam (at the expense of the clarity and detail some of us crave). What's a head-fier to do?

kwkarth has suggested a few times that a subwoofer combined with his K1000's is a beautiful combination. Read more about it in this thread; Real Headphone Bass at Home.

If we were to design a subwoofer specifically for headphone use, how would it work? Would you build an amp in the cabinet, one for the headphones and one for the subwoofer? Would you have a crossover so only the frequencies above the subwoofer rolloff would go to the headphone amp, or run the headphones full range? What about volume control and level control for the subwoofer?

Let's think!
 
Apr 22, 2002 at 6:31 AM Post #3 of 28

RMSzero

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I would think that you'd want the subwoofer to act more as a vibration enhancer than detail. So you would want to run the headphones full range, or at least so that your ears hear the detailed bass, while your toes and chest feel the thump.

I've never tried it though. Sounds like a fun project.
 
Apr 22, 2002 at 7:38 AM Post #4 of 28

Lizard_1

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Quote:

Originally posted by Jeff Guidry
Most of us use headphones as a comprimise because we can either not afford a full sized system, or we don't have the space for one. Also, it's difficult to listen to music at satisfying levels without disturbing the neighbors, roommates or significant others (if you're bisexual, would it be significant eithers?).


Maybe an armchair with a build in sub, or a vibrator for more specific needs.
biggrin.gif
 
Apr 22, 2002 at 1:44 PM Post #5 of 28

BeeEss

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RMSzero, you've hit the nail right on the head. In pro audio a huge trend right now is in-ear monitoring (IEM). In essence, the artist/band uses an Etymotic-like headphone (normally with custom earmolds) instead of traditional wedge monitors. Advantages are numerous in this situation, including dramatically lower stage volumes and a cleaner overall stage sound without monitor wedge washout. It is usually (no surprise) an easy sell to singers and guitarists but until recently has been a difficult sell to drummers. The reason is that many, many drummers are accustomed to a LARGE drum monitor setup, most likely somewhere in the neighborhood of 1000 watts and 2 18" subwoofers and 2 15" horn-loaded PA cabs. (As an interesting sidenote, this type of setup has been known to be called by pro audio veterans as "Texas headphones"
rolleyes.gif
) Anyway, veteran drummers are just too accustomed to the visceral slam from those subwoofers practically underneath their butt, and you don't get that from the IEM's. Enter the Aura Bass Shaker.

http://www.pcguild.com/newsensaphonics/aura.html

This little gem mounts to the drummer's throne and shakes the hell out of it in time with the signal, normally a small amplifier and crossover are used. And the result is quite amazing, I personally know many drummers who we thought would never go for it who are now using it on a regular basis and loving it. They say the only thing they miss about the Texas headphones is how cool it made their kit look
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.

Implications for hifi? I really don't claim to know. I am surprised I have not heard more talk about this thing on this board, maybe I just missed it but I am sure that there are some that have tried it. It doesn't make a lot of noise, depending on how solidly it is mounted. It is a fun gadget to play with, if nothing else. The results are kinda surprising. I think it would be killer in a HT setup, imagine the couch shaking every time something blew up
very_evil_smiley.gif
. Anyway, just food for thought.....
 
Apr 22, 2002 at 3:17 PM Post #7 of 28

2 channel

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I have 6 bass shakers attached to my sofa in my theatre and let me tell ya...WOWEEE! It is a whole different HTR experience! I have not tried it with my headphones as I don't use my HTR receiver with them, but perhaps I will try it.
Hey, maybe Till can get a bass shaker and a fold up ikea type lounge chair of some sort to take on the WOH tour.
 
Apr 22, 2002 at 5:48 PM Post #8 of 28

gerG

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Hi Jeff.

I have been working on a better subwoofer design for my K-1000s. They need it because they are missing the lowest octave. Right now I am using an ADS PB1500 in nearfield, which eliminates most of the room resonance and results in very controlled LF. I use an electronic crossover with the K1000 amp high passed at 70 hz. That cleans them up due to drastically reduced driver excursions. The low pass goes to the sub.

I haven't come up with a sub that is wearable yet. I could see a wearable version of those bass shaker things, but it isn't for me. They don't provide the missing acoustic information that I am after. That leaves me with some sort of box sitting on the floor or under a chair. What I am after is minimizing the acoustic input to the room, while restoring what is missing from my phones. I am trying to get the output closer to my ears, but with enough tolerance to move around in my chair without affecting the response.

I haven't tried any other cans with the current sub. It is an easy experiment. I mentioned on the Ety bass thread that I will try the sub as an "augmentor" tonight. If I get anything interesting I can hook them up with the Shoguns and try to blur out my vision!

Anything else I should check?


gerG
 
Apr 22, 2002 at 6:50 PM Post #9 of 28

ai0tron

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In terms of high fidelity I don't think adding a subwoofer is going to improve the sound of the headphones. Although it may make for a more interesting experience. Personally, when I have used a subwoofer with my HD600's I find that it blurrs the midrange alot. I think this has something to do with time delays.

The bass is very good from the HD600's themselves anyway so i don't really see a reall driving reason to add a subwoofer.
 
Apr 22, 2002 at 7:25 PM Post #10 of 28

gerG

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I do have some concerns about adding a sub to open phones. The airborn acoustic waves have to go through the driver diaphragms. That can't be a good thing. Of course, that won't stop me from trying it
biggrin.gif


I have never found the HD600s to be particularly lacking bass.

A couple of days ago I was listening to music out of my llaptop PC (that is pronounced yaptop). I decided to goof around with a new piece of RTA software. I was feeding a low level 25 hz tone to my phones, trying to figure out where my hearing rolls off. The remarkable thing was the distortion that I heard from the television, which my wife was watching in the next room. IM distortion my eardrums??? How the hell am I going to upgrade those things?


gerG
 
Apr 23, 2002 at 3:53 AM Post #12 of 28

kwkarth

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Yup, ai0tron's right. The 600's don't need a sub and frankly, wouldn't work too well with one anyway. The only sort of can that will work with a sub is an open can like the K1000 or the Sony F1. The bass doesn't have to pass through the diaphragm to reach your ear. Further, the bass roll off of the K1000 is rather sharp naturally, so it's easy to pick a good crossover point (about 45Hz for the K1000's) A near field sub works best.
 
Apr 23, 2002 at 4:23 AM Post #13 of 28

Dusty Chalk

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Two things:

1 - a subwoofer for headphones should be the same as a subwoofer for speakers -- you either match the slope with the natural slope of the headphones, or you put the crossover in front of the headphone amp.

2 - a respectfully disagree with the consensus that you need a sub. I sincerely believe in the psycho-acoustic effect of good headphones, combined with a good amp and good source, you really can feel the bass in your gut. My reference for this is DT770, RKV, MSB Link Tech DAC III, or the DT770 with Creek OBH11SE and AA DDE v3.0.

I was listening to something, I forget what, and I actually took off my phones to see if I accidentally left my sub on again. I hadn't.
 
Apr 23, 2002 at 4:24 AM Post #14 of 28

markl

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The ATW2002 with DADS system is sorta like what you're talking about. I described the effect as "ear massage". I liked it, not everyone did.

markl
 
Apr 23, 2002 at 6:03 AM Post #15 of 28

Jeff Guidry

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I was thinking more about developing a subwoofer unit for the Etymotics, which are clearly incapable of producing visceral bass, and for all other headphones like them (K-1000's, K-501's) that could use a hand to produce a more physical effect. For some, the thump is very important, and even bass heavy headphones like my V6's just don't give that KICK.

I was hoping someone would mention bass shakers, which I think would be an excellent compromise.

If you were developing a system with a subwoofer, or with a bass shaker, what would it look like? How would it work?
 

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