Hi again,
Anyone here have experience with Aperiodic vented sub enclosures? It
seems like an easy way to get more low end out of a smaller than optimal
enclosure. Richard Clark was doing this in the late 80s. His aperiodic
vents were around $200 / pair and way out of reach for many.

Parts Express sells a Scan Speak vent for relatively little money.

What are the pros/cons to this design? Thinking about giving it a try.

thanks,
Garrett

Sanitarium wrote:



Hi again,
Anyone here have experience with Aperiodic vented sub enclosures? It
seems like an easy way to get more low end out of a smaller than optimal
enclosure. Richard Clark was doing this in the late 80s. His aperiodic
vents were around $200 / pair and way out of reach for many.

Parts Express sells a Scan Speak vent for relatively little money.

What are the pros/cons to this design? Thinking about giving it a try.

thanks,
Garrett

I've tested the AutoSound2000 device and, well, it was underwhelming. It had a
fibrous pad that you placed over the front of a woofer that added some
mechanical damping along with a EQ device that pretty much restored the lower
end output lost by the damping pad.

I also listened to it by placing the pad on and off the face of a 12-inch
woofer installed in an infinite baffle arrangement in a Honda CRX. The net
result was that I was unabl etohear any change in response with/without the
pad. There were minor (less than a dB at 30 Hz) measured differences but
overall the sound of the system was identical with/without the pad and EQ.

There's another type of 'aperiodic' approach that generally involves installing
a small leak in a sealed enclosure. Audio Concepts used to do this. In the
early 70s Dynaco had a port/stuffing system said to be aperiodic; but none of
them had any special performance quality that could be 'caused' by the
technique as far as I could tell.

In article , (Nousaine) wrote:
Sanitarium wrote:



Hi again,
dentical with/without the pad and EQ.

There's another type of 'aperiodic' approach that generally involves installing
a small leak in a sealed enclosure. Audio Concepts used to do this. In the
early 70s Dynaco had a port/stuffing system said to be aperiodic; but none of
them had any special performance quality that could be 'caused' by the
technique as far as I could tell.

And you hear many worrying about having their enclosure absolutely leak free.
You don't want whistles, but enough is enough.

greg

Hmm... Heres the Idea I have for my old accord hatch back, what do you
think?

The 2 12" subs I have are designed for a 1.5-2 cubit foot sealed
enclosure. I need as much trunk space as possible, so I would like to
make an enclosure that has 1 cubic foot or less for each sub.`

Each sub would fire forward from its own sealed 1 cubic foot enclosure.
One Scan speak vent per subwoofer would face downward and vent into the
spare tire cavity. I am building up a hinged trunk floor that can be
removed for spare tire access. From what I understand the aperiodic
vent should not be venting into the same listening area as the subs, so
I'd like to try and isolate the 2 this way, taking advantage of the air
volume in the spare tire well.

Does it matter that the spare tire is down there occupying volume air
space?

Thanks,
Garrett

Nousaine wrote:

Sanitarium wrote:



Hi again,
Anyone here have experience with Aperiodic vented sub enclosures? It
seems like an easy way to get more low end out of a smaller than optimal
enclosure. Richard Clark was doing this in the late 80s. His aperiodic
vents were around $200 / pair and way out of reach for many.

Parts Express sells a Scan Speak vent for relatively little money.

What are the pros/cons to this design? Thinking about giving it a try.

thanks,
Garrett

I've tested the AutoSound2000 device and, well, it was underwhelming. It had a
fibrous pad that you placed over the front of a woofer that added some
mechanical damping along with a EQ device that pretty much restored the lower
end output lost by the damping pad.

I also listened to it by placing the pad on and off the face of a 12-inch
woofer installed in an infinite baffle arrangement in a Honda CRX. The net
result was that I was unabl etohear any change in response with/without the
pad. There were minor (less than a dB at 30 Hz) measured differences but
overall the sound of the system was identical with/without the pad and EQ.

There's another type of 'aperiodic' approach that generally involves installing
a small leak in a sealed enclosure. Audio Concepts used to do this. In the
early 70s Dynaco had a port/stuffing system said to be aperiodic; but none of
them had any special performance quality that could be 'caused' by the
technique as far as I could tell.

The ScanSpeak vents are meant for midbass drivers of moderate size. I
don't believe one per woofer will provide enough damping resistance to
control a large woofer such as a 12" sub. Generally with AP vents one
stuffs more material between the layers of grille as required. I just
don't think you can stuff much more into what those ScanSpeak vents
can hold already. You would probably need more than one.

There is a good tutorial in AP enclosures over on Elite Caraudio.
www.elitecaraudio.com


On Wed, 09 Jul 2003 09:55:39 -0700, Sanitarium
wrote:

Hmm... Heres the Idea I have for my old accord hatch back, what do you
think?

The 2 12" subs I have are designed for a 1.5-2 cubit foot sealed
enclosure. I need as much trunk space as possible, so I would like to
make an enclosure that has 1 cubic foot or less for each sub.`

Each sub would fire forward from its own sealed 1 cubic foot enclosure.
One Scan speak vent per subwoofer would face downward and vent into the
spare tire cavity. I am building up a hinged trunk floor that can be
removed for spare tire access. From what I understand the aperiodic
vent should not be venting into the same listening area as the subs, so
I'd like to try and isolate the 2 this way, taking advantage of the air
volume in the spare tire well.

Does it matter that the spare tire is down there occupying volume air
space?

Thanks,
Garrett

Nousaine wrote:

Sanitarium wrote:



Hi again,
Anyone here have experience with Aperiodic vented sub enclosures? It
seems like an easy way to get more low end out of a smaller than optimal
enclosure. Richard Clark was doing this in the late 80s. His aperiodic
vents were around $200 / pair and way out of reach for many.

Parts Express sells a Scan Speak vent for relatively little money.

What are the pros/cons to this design? Thinking about giving it a try.

thanks,
Garrett

I've tested the AutoSound2000 device and, well, it was underwhelming. It had a
fibrous pad that you placed over the front of a woofer that added some
mechanical damping along with a EQ device that pretty much restored the lower
end output lost by the damping pad.

I also listened to it by placing the pad on and off the face of a 12-inch
woofer installed in an infinite baffle arrangement in a Honda CRX. The net
result was that I was unabl etohear any change in response with/without the
pad. There were minor (less than a dB at 30 Hz) measured differences but
overall the sound of the system was identical with/without the pad and EQ.

There's another type of 'aperiodic' approach that generally involves installing
a small leak in a sealed enclosure. Audio Concepts used to do this. In the
early 70s Dynaco had a port/stuffing system said to be aperiodic; but none of
them had any special performance quality that could be 'caused' by the
technique as far as I could tell.



Stephen Narayan | IASCA Pro Street 1-600 | IASCA Certified Judge 2003
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