calling all push pull and isobaric set ups!!

[sonoma99beast]

lets see em, im building one for my sonoma and wanna see how they look and sound in our trucks

[juddspaintballs]

Probably aren't even more than 1 or 2 on this forum.

[BlazerChops]

Both are good designs and can sound great if done right.

Isobarics are good because you have twice the amount of woofers in half the space of one. Even in a "so-so" designed ported enclosure, you can get some really tight, punchy bass. The neat thing about isobaric designs is that say you have a driver that requires 1cf of air space. Well, when you isobarically load them, you can now run both subs in as little as 0.5cf of air space. This system can handle twice as much power as the single driver variant. However, the main drawback of this design is the fact that it is somewhat inefficient.

Push-Pull designs are great because you also get twice as many woofers as well as improving the efficiency and power handling, however you also have to use twice the air space as you would normally with two woofers. This design also provides plenty of tight and punchy bass. And if it is a proper Push-Pull design (one driver facing in, one facing out and electrically out of phase), they will cancel out even-order harmonic distortion.



When I first met one of my friends years ago, he had 4 JL 12w4's in an isobaric configuration, in about a 3cf ported enclosure tuned to I think 25Hz and powered by a PPI 2150M. all of this crammed into a Geo Storm GSI. That system pounded, especially with the Epicenter bumped up some.


My very first vehicle, I had a pair of Pyramid Phase III 10's (the clear cones) in a small 1cf ported enclosure tuned to 32Hz, also isobarically loaded. It was powered by an Audio Art A240 amp. Obviously, this was before I got into JL and AudioControl products, but even those cheap drivers sounded damn good and pounded my '91 Ford Ranger hard.


Now as for Push-Pull subs, up to about 6 months ago, I had a push-pull sub in my home theater that I built myself using a pair of Dayton DVC 15's and a Crown Xti-1000 amp (1000 watts @ 8 ohms). The enclosure was a perfect cube and 6cf sealed. It was ugly as hell, but sounded better than anything else you could fine at the price.

And just for fun...

[juddspaintballs]

heh, 80's wood fashion paneling FTW

[old_skool_noma]

i can has teh ibanez 5 string :drools:

and damn thats a nice home theater setup

[BlazerChops]

Quote: Originally Posted by juddspaintballs

heh, 80's wood fashion paneling FTW

LOL... Trust me, not my choice by any means.

[BlazerChops]

Quote: Originally Posted by old_skool_noma

i can has teh ibanez 5 string :drools:

and damn thats a nice home theater setup

Damn dude, either you have a good eye or you snuck over to my website. haha

And thanks for the props. Obviously, all DIY loudspeakers. Those were 5 Usher 15HM 15" drivers, 3 original Altec 511B horns and 902-8B drivers from Voice Of The Theater speakers (VOTT), a purely digital, fully active crossover system for all 3 front channels, 3 stereo amplifiers and a lot of time voicing them to near perfection. The 2 main channels were Open Baffle (the backs were completely open just like the front).

How does 106dB @ 1 watt tickle you? No more than 10 watts input was ever needed, and the main speakers were quite capable of solid, usable bass down to 22Hz. Of course, there was a lot of EQ to get it there, but it got there.








Now I have downsized and improved to this... Still partially open baffle (the 2 top mids on the mains and the 2 middle mids in the center channel). The other drivers are all sealed. The sub is ported and tunable from 25Hz to 20Hz to 16Hz and has two 12's and 900 watts rms. This setup gives me much more needed room and a lot better imaging and soundstaging. Plus the entire system is considerably simplified.

[old_skool_noma]

just that good of an eye, i hapen to like the ibanez basses since one of my friends has a really nice active one and ive been trying to get him to trade his for my p bass since he like thge tone of the p bass and i like the tone of his actives

[juddspaintballs]

i'll have to admit i did cum a little when i saw the first setup. your current one is impressive still, but damn dude on the first one.

[BlazerChops]

Quote: Originally Posted by old_skool_noma

just that good of an eye, i hapen to like the ibanez basses since one of my friends has a really nice active one and ive been trying to get him to trade his for my p bass since he like thge tone of the p bass and i like the tone of his actives

Honestly, I haven't touched that bass in a while now. I bought a new set of RotoSound round-wound strings for it, played it for about a week, then parked it. It's been sitting ever since. The entire thing is in perfect shape. You want it?

[BlazerChops]

Quote: Originally Posted by juddspaintballs

i'll have to admit i did cum a little when i saw the first setup. your current one is impressive still, but damn dude on the first one.

That's just nasty...






















But thank you!

[sonoma99beast]

well i have already had sealed, ported, bandpass and down fire in my truck and im not to happy with any so far

[BlazerChops]

Quote: Originally Posted by sonoma99beast

well i have already had sealed, ported, bandpass and down fire in my truck and im not to happy with any so far

Must have been the wrong amp with the wrong sub in the wrong size enclosure tuned to the wrong frequency with the wrong type of music.

With a pickup, you could do one hell of an infinite baffle setup via a blow-thru. Not necessarily the best for all-out SPL but excellent for ultimate SQ and bass extension with the right drivers.

[eriley]

Quote: Originally Posted by BlazerChops

And thanks for the props. Obviously, all DIY loudspeakers. Those were 5 Usher 15HM 15" drivers, 3 original Altec 511B horns and 902-8B drivers from Voice Of The Theater speakers (VOTT), a purely digital, fully active crossover system for all 3 front channels, 3 stereo amplifiers and a lot of time voicing them to near perfection. The 2 main channels were Open Baffle (the backs were completely open just like the front).

How does 106dB @ 1 watt tickle you? No more than 10 watts input was ever needed, and the main speakers were quite capable of solid, usable bass down to 22Hz. Of course, there was a lot of EQ to get it there, but it got there.

Where do I learn to do this. I've read a lot of stuff on the internet and I guess actually doing it plays a lot into it but I would barely even know where to start

[BlazerChops]

Quote: Originally Posted by eriley

Where do I learn to do this. I've read a lot of stuff on the internet and I guess actually doing it plays a lot into it but I would barely even know where to start

Go to http://www.diyaudio.com and start searching and reading. Be warned though, there are a bunch of dicks on there so be careful.

[paint toad]

And if it is a proper Push-Pull design (one driver facing in, one facing out and electrically out of phase), they will cancel out even-order harmonic distortion.





no........with the drivers set up like that they must be wired in phase......

now if they were both facing in or both facing out then you would wire them out of phase to achieve the push pull

[BlazerChops]

Quote: Originally Posted by paint toad

no........with the drivers set up like that they must be wired in phase......

now if they were both facing in or both facing out then you would wire them out of phase to achieve the push pull

Nope. Sorry, but wrong.

If one driver is facing INTO the enclosure and the other one is facing OUT OF the enclosure, they have to be wired electrically out of phase or you end up with nothing more than a bi-polar subwoofer, thus canceling eachother out and creating very little if no bass at all.

Since one is facing into the box and one is facing out of the box, they have to be wired out of phase so both cones move into the box at the same time and move away from the box at the same time. Since one cone is moving into its basket and motor system while the other one is moving out of its basket and motor system, they are acoustically in-phase and are canceling out their even harmonics.

The key to making it work is both cones have to move towards eachother and away from eachother to produce sound... a.k.a. - pressurizing and depressurizing the enclosure.

I have a little personal experience with several different ones over the years, this being the last one just under a year ago.

[paint toad]

^^^^^ well that is neither push pull nor isobaric....i dunno what you call that.....

push pull or isobaric setups have the cones moving with each other not battling each other

[BlazerChops]

Quote: Originally Posted by paint toad

^^^^^ well that is neither push pull nor isobaric....i dunno what you call that.....

push pull or isobaric setups have the cones moving with each other not battling each other

Wrong again...

That's push-pull, plain and simple. The drivers are not battling eachother.

It's the same exact principle as having two drivers in one common chamber with both cones facing forward like a pre-fab wedge enclosure for a pickup. Yes, both drivers are facing the same direction, but both cones are also moving into and out of the enclosure at the same time, pressurizing and depressurizing the air inside.

Mine above is the exact same, minus one driver being inverted and wired out of phase, thus becoming push-pull. The "Push-Pull" means that one cone is pushing away from its motor structure while the other one is pulling towards its motor structure. That's how they cancel their even harmonics out.

[paint toad]

http://www.hometheatershack.com/foru...subwoofer.html

post 14



i'm getting conflicting results searching this......so i'm giving up.....but to me push pull means one driver is pushing the air while the other pulls the air....that's the way i've always understood it and that is the only way it makes sense to me.......

but if what you say is true then my monitor audio asw-210 sub(ported) is push-pull but only in the sense that both drivers are pushing in or both drivers are pushing out ....but that's any speaker so i guess all speakers are push pull.....


anyway....nice discussion

[paint toad]

from bass box 6 on screen glossary:

push-pull-- When two drivers are mounted in opposite directions and wired with opposite polarity with respect to each other, they are said to be in a “push-pull” configuration. This is because when the cone of one driver moves away from its magnet, the other driver’s cone moves toward its magnet. This results in a reduction in even-order distortion because many suspension nonlinearities are cancelled.

Copyright 1992-2002 by Harris Technologies, Inc.


isobaric --Constant pressure. A “compound” pair of drivers are mounted on either end of a small, sealed isobaric chamber. The pressure in the chamber is kept constant because both drivers are fed the same signal and their diaphragms move in the same direction.


Copyright 1992-2002 by Harris Technologies, Inc.

[BlazerChops]

Quote: Originally Posted by paint toad

from bass box 6 on screen glossary:

push-pull-- When two drivers are mounted in opposite directions and wired with opposite polarity with respect to each other, they are said to be in a “push-pull” configuration. This is because when the cone of one driver moves away from its magnet, the other driver’s cone moves toward its magnet. This results in a reduction in even-order distortion because many suspension nonlinearities are cancelled.

Copyright 1992-2002 by Harris Technologies, Inc.

That's exactly what I just said... Twice.

Quote:

isobaric --Constant pressure. A “compound” pair of drivers are mounted on either end of a small, sealed isobaric chamber. The pressure in the chamber is kept constant because both drivers are fed the same signal and their diaphragms move in the same direction.


Copyright 1992-2002 by Harris Technologies, Inc.

That is ONLY referring to the air trapped between the two cones, not the air in the enclosure that the one driver is actually mounted in. Remember, with isobaric loading, one of the two drivers still needs to be mounted in a traditional enclosure of some kind.

Also with isobarics, mounting the drivers face-to-face (clamshell) either right to eachother or a very small sealed chamber between them, will still cancel out even harmonics since the cone of one driver is moving out of the motor structure as the other is moving into the motor structure.

[BlazerChops]

Quote: Originally Posted by paint toad

http://www.hometheatershack.com/foru...subwoofer.html

post 14



i'm getting conflicting results searching this......so i'm giving up.....but to me push pull means one driver is pushing the air while the other pulls the air....that's the way i've always understood it and that is the only way it makes sense to me.......

but if what you say is true then my monitor audio asw-210 sub(ported) is push-pull but only in the sense that both drivers are pushing in or both drivers are pushing out ....but that's any speaker so i guess all speakers are push pull.....


anyway....nice discussion

Sorry, I can't see the link since I got banned from that crappy site a couple years ago. Too many stuck-up dickheads on there that think they know everything, brown-nose the admins and mods, and gang up on people like a freakin' pile-up. Yeah, that site sucks ass, as do most of the members.

Don't give up, figure it out. You've been in this business for a while now, it should come to you like nothing. Push-pull has nothing to do with how the air is moved, just the motion of the cones.

What I say IS true and not all speakers are push-pull, only the ones that have one driver inverted and wired out of phase. Years ago, and I mean years ago, like back in the mid to late 70's and early 80's, home audio loudspeaker companies like Allison, KEF, Advent and a couple others made tower speakers that were push-pull. In fact M&K, a company that started out building only subwoofers still make subwoofers that are push-pull. They are the ones who really pushed this design on the market as a great success. The reason most companies got out of making towers that way was because of the looks of the overall product. People didn't like seeing a magnet staring them in the face. It's funny how some people who claim to be audiophiles prefer looks of something over the sound of something. Obviously, they're not true audiophiles.

And no, your Monitor Audio ASW-210 is not push-pull since neither driver is inverted. BTW, I had the RS-6 towers for a couple moths a little while ago. They sounded great except for the bright and brittle tweeters. What a shame because they are highly regarded and they looked great. Oh well...

[paint toad]

Re: Correct speaker phase in push pull subwoofer
Quote:
mgboy wrote:
Well in that case, I believe they should be wired in phase, otherwise they cones would be moving in opposite directions and there would be a direct cancellation. Correct bill?

Yes. The would be wired reverse polarity as shown, but if both drivers are outward facing per the OPs version they'd be wired normally. They would be moving in opposite directions, but only because they're on opposite sides of the box. Both are moving either inward or outward simultaneously. BTW, that's not an isobaric alignment.

Bill Fitzmaurice








i'll give you the description of push-pull due to my lack of sleep and poor comprehension for the past week(even though i don't agree)......but you are confused about isobaric because isobaric only refers to the loading of the chamber....not the rest of the enclosure which can be any other type of enclosure

[paint toad]

i thought m & k was done....i saw buyout drivers in parts express ''from the now defunct m & k" awhile back

[BlazerChops]

Quote: Originally Posted by paint toad

Re: Correct speaker phase in push pull subwoofer
Quote:
mgboy wrote:
Well in that case, I believe they should be wired in phase, otherwise they cones would be moving in opposite directions and there would be a direct cancellation. Correct bill?

Yes. The would be wired reverse polarity as shown, but if both drivers are outward facing per the OPs version they'd be wired normally. They would be moving in opposite directions, but only because they're on opposite sides of the box. Both are moving either inward or outward simultaneously. BTW, that's not an isobaric alignment.

Bill Fitzmaurice








i'll give you the description of push-pull due to my lack of sleep and poor comprehension for the past week(even though i don't agree)......but you are confused about isobaric because isobaric only refers to the loading of the chamber....not the rest of the enclosure which can be any other type of enclosure

I most certainly am not confused about any of this. I've built plenty of both designs over the years. I studied and researched these designs years ago.

Re-read what I said about isobaric loading. Not once did I ever mention it being the way it loads the enclosure.

I SAID that one of the drivers still has to be mounted in a traditional enclosure... Meaning that you can not just mount two drivers to a single chamber and expect to get something out of it. Doing this, you would end up with a simple di-pole speaker where the out of phase sound cancels itself out. THAT chamber with both drivers mounted to it still needs another chamber (an enclosure) to trap and/or tune the backwave of one of those drivers in order to make it a normal mono-pole system.

You need to either get some serious sleep and re-read everything I've wrote or go research everything you're trying to debate with me and realize I'm correct, because so far you're not impressing me and not helping others with the information you're giving out at the moment.

And quoting bits and pieces of someone else's conversations that you don't fully read or understand isn't helping any either.

I'm not trying to be a dick or anything, but damn.