exhaust too loud?

ChrisJ

ChrisJ

Active member
You know I never got into bandpass subs much. I've always been a acoustic suspension, or rarely a passive radiator kind of guy. Other types are either have too narrow of a response, or are just plain noisy (high velocity through ports). Actually to be honest I've never heard a port I liked, they are always noisy. Passive radiator is as vented as I go.

That said, you are thinking of relating a bandpass sub enclosure (theory wise) for an exhaust system? You do realize the engine doesn't just run at 3,000rpms right? You would need to tune it from at least 2000-6000rpm and thats not realistic.

I beleive this is actually a real problem even with normal exhaust systems, ever heard where your exhaust gets louder at a specific RPM and then gets quiet again?

It also reminds me of how expansion chambers for 2 strokes work, though they intentionally create a huge amount of backpressure at one point and not consistently.

Audio has been a hobby of mine for 25 years, though I've done little speaker desinging I'm mainly into the amplifier side of things. Have designed and built a few of my own. Also into restoring vintage stuff and right now I am working on repairing a Yamaha 6 channel receiver with 4 port HDMI switch.


An example of my work, these have onboard linkwitz-riley crossovers and bolt into the backs of two of my speakers.

https://sphotos-a.xx.fbcdn.net/hphotos-ash4/340178_10150663014091253_1746585492_o.jpg


Sorry for rampling. :D
 
Quinton Exler

Quinton Exler

New member
ChrisJ, amazing work! And tbh you can create a 4th order bandpass properly to play notes just as well as a properly made ported box could, it will hit notes in the 20s even when done properly... And no air would be heard.

EDIT:
And as I said a while back in posts, it will actually push more air than a normal ported enclosure could only when done properly.
 
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ChrisJ

ChrisJ

Active member
Quinton Exler said:
ChrisJ, amazing work! And tbh you can create a 4th order bandpass properly to play notes just as well as a properly made ported box could, it will hit notes in the 20s even when done properly... And no air would be heard.

EDIT:
And as I said a while back in posts, it will actually push more air than a normal ported enclosure could only when done properly.
Click to expand...

Thank you for the compliment, I put a lot of work into that amp design though its only 200W (230W at clipping) for woofer and 50W (59 at clipping) for tweeter. They have a 12dB\octave crossover as well as a 24dB\octave version.


As far as ported enclosures,

I'll believe it when I hear it. Keep in mind, I feel ported boxes are also peaky in my book a good enclosure will do 20Hz-250Hz +-3dB.

Yes, I know, SUBs arn't normally used over 60-80Hz but as you know home systems which I usually deal with are different than cars. I also believe in stereo subs.

My last car system was a pair of A/D/S/ 312RS in a sealed enclosure driven by an A/D/S/ 830X amp bridged to 4 channel. Highs were by an A/D/S 430X and the headunit was a 2nd from top of the line Eclipse. Of course this was in 2004 and the A/D/S/ stuff I bought broke used as by 2004 A/D/S was already bought out and making cheaper stuff. Those 312RS in the 1" MDF enclosure I had for them were nearly flat from 30Hz to 1KHz, though I had an active lowpass crossover on them.

If you're in or near NJ I wouldn't mind hearing some of your stuff. I've just never heard, or saw on paper a ported enclosure of any type that was not peaky.


Sorry if I sound like an audiophile, I can't stand those people anymore.
 
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Quinton Exler

Quinton Exler

New member
You sir, just met someone who can easily design a non peaky 4th order enclosure that will play a great span of notes very well. and drop gut wrenching low. I currently do not have a system installed... I was thinking about a single 6.5" american bass subwoofer in a 4th order. The video below is a video of a Quasi 6th order design I had done... You can't hear any chuffing in this enclosure at all... and it got LOW. also played every note in a test sweep from 100-25hz really strong.

please watch it all.

http://www.youtube.com/watch?v=8t6dutYrMOk
 
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ChrisJ

ChrisJ

Active member
Quinton Exler said:
You sir, just met someone who can easily design a non peaky 4th order enclosure that will play a great span of notes very well. and drop gut wrenching low. I currently do not have a system installed... I was thinking about a single 6.5" american bass subwoofer in a 4th order. The video below is a video of a Quasi 6th order design I had done... You can't hear an chuffing in this enclosure at all... and it got LOW. also played every note in a test sweep from 100-25hz really strong.

please watch it all.

One Aq hdc 3.0 10" Flexing everything - YouTube
Click to expand...



Ok I'll be honest, I have always wanted to mess with folded corner horns in the house. Have any experience with them? Send me a PM so we don't tie up the thead about audio.

BTW, I've moved stuff in a 12x20 room like that using two 18's in enclosures that were rated something like 108db @ 1 watt @ 1 meter.
 
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