Aperiodic thoughts ???

[blue 10+ year member]

Spoke with Matthew at Alumapro today , and told him how much more I enjoyed my 10" Alchemys than I do my 12" ones ...... Here's the details : Same solid , sealed box construction .... Same amplification and high quality asociated components upstream. Both sizes installed in the reccomended enclosures .

My question to Matthew was , could I get closer to the sound of the 10's by making the 12's enclosure smaller. His response was NO .... Said I needed to actually go larger with the enclosure for the 12's ...... Lowering the " Q " Since I'm NOT making another enclosure at this time , he suggested buying a pair of the Scanspeak Aperiodic membranes from Madisound. //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif :eyebrow: //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif I've never had good luck with Aperiodic membranes in the past .....

Care to lend your thoughts ?

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[johnecon2001 5,000+ posts]

something about causing the waves to bounce around more.. from what I remember.

 

[PV Audio 5,000+ posts]

i wouldn't go with an aperiodic alignment unless you are either that pressed for space or know EXACTLY what you are doing.

 

[blue 10+ year member]

i wouldn't go with an aperiodic alignment unless you are either that pressed for space or know EXACTLY what you are doing.

Well .... I could build the ****ed box larger if I had too , but I REALLY don't want to. It may sound even worse , and then I've went to a LOT of work , when an Aperiodic would be an easy thing to try ..... cheap too. I don't see what the big deal would be ..... You simply install it and see how it sounds .... There is no tuning the device.

My other alternative would be to just buy two 10's again ..... I KNOW how awesome they sound with their lower Q .....

 

[blue 10+ year member]

Maybe I should clarify ..... I'm NOT talking about building a complete Aperiodic , dual chamber enclosure ...... I'm talking about placing a couple of the 6" membranes in the bottom of the box .... Making the woofer think it's in a box that is about 25% larger ..... That's all ....

 

[blue 10+ year member]

Guess I could also stuff the enclosure with Polyfill .... That will fool the woofer also.

 

[johnecon2001 5,000+ posts]

yeah that would work as well.. I dont know if it would give you the tight sound that the ten did. Nothing I've owned since I bought those has really compared at all. Tweaking.. gonna have to do a lot of that to get the 12 to sound the same.

 

[smgreen20 10+ year member]

Well .... I could build the ****ed box larger if I had too , but I REALLY don't want to. It may sound even worse , and then I've went to a LOT of work , when an Aperiodic would be an easy thing to try ..... cheap too. I don't see what the big deal would be ..... You simply install it and see how it sounds .... There is no tuning the device.My other alternative would be to just buy two 10's again ..... I KNOW how awesome they sound with their lower Q .....

It's not as easy as you seem to think. There's a science to making one of those boxes. Sandwiched insulation and a few resistors are involved to determain how big the box needs to be. I had a guy teach me a few years back and don't remember a whole hell of a lot about it, but it wasn't easy.

 

[PV Audio 5,000+ posts]

^^^

 

[Hundreth 10+ year member]

I'm kind of confused... normally if you want to make a sub sound tighter, you make the box smaller. Making the box bigger will make it sound less tight and more smooth/transient.

 

[squeak9798 5,000+ posts]

Well .... I could build the ****ed box larger if I had too , but I REALLY don't want to. It may sound even worse , and then I've went to a LOT of work , when an Aperiodic would be an easy thing to try ..... cheap too. I don't see what the big deal would be ..... You simply install it and see how it sounds .... There is no tuning the device.

There is no tuning of THAT device. To optimize an AP setup, there should be tuning involved by adding/removing material, etc.

 

[squeak9798 5,000+ posts]

Sandwiched insulation and a few resistors are involved to determain how big the box needs to be.

Box size isn't hard //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif It only has to be large enough to house the woofer and the AP membrane.

AP is basically nothing more than IB with a resistive membrane.

 

[smgreen20 10+ year member]

Box size isn't hard //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif It only has to be large enough to house the woofer and the AP membrane.
AP is basically nothing more than IB with a resistive membrane.

It's been a long a$$ time since I messed w/one. Forget most on how to do it.

 

[blue 10+ year member]

There is no tuning of THAT device. To optimize an AP setup, there should be tuning involved by adding/removing material, etc.

Very correct Sqeak ..... But THAT device is exactly what Matthew at Alumapro suggested I try ..... He simply wants the subs to have a lower Q.

 

[blue 10+ year member]

I'm kind of confused... normally if you want to make a sub sound tighter, you make the box smaller. Making the box bigger will make it sound less tight and more smooth/transient.

Well ..... Tighter and transient go together ......

Matthew believes the 12's have more energy between 40 and 70 hz , and he thinks THAT is ever so slightly muddying up the bass , when compared to 10's ..... A agree with this in THIS case. Going to a larger enclosure would take away the slight " peak " in that 40 to 70 region , possibly making the bass less muddy.