Ported SW-12B subwoofer questions

tryin · « **on:** 11 Mar 2010, 01:44 am »

Thinking about using an SW-12B and apex sr. for a cheap ht/ music sub. I've been doing some research and it appears that this sub's down 3db at around 40hz in a sealed configuration, not going to cut it for HT. Since the passive radiator is no longer available, it looks as though I would have to build the ported version to get extension into the 20's. I've read that the ported enclosure should be 2.3 cu.ft. but no mention of port size/ length. Anyone build a ported one? I can't really find anything.

Should I even consider this sub in a ported configuration?

Thanks!

Danny Richie · « **Reply #1 on:** 12 Mar 2010, 03:32 am »

Ported is no problem. You can get good extension with a -3db down point in the low 20's. However, it does require a pretty damn big port.

Or you could go with a 1.2 cubic foot sealed cabinet with one of our new amps.

This little amp does 200 watts into 4 ohms and 110 watts into 8 ohms.

The really cool thing is the output response. I had a circuit designed that would mirror image the roll off of a sealed box or open baffle design.

See my measured output:

The Red line is the measured output of the amp that I use with my Clio.

The green line is with the crossover set all the way up. The Purple line is with the crossover setting about half way up. And then the Blue line is with the crossover turned all the way down.

As you can see, with this amp, you will get a -3db in the low 20's in a small sealed box.

Here is a factory made measurement:

The Red line is with the crossover turned all the way up and the Purple line is with it turned all the way down.

Amps are in stock and cost $129 each.

Now how is that for a deal?

HT cOz · « **Reply #2 on:** 12 Mar 2010, 04:07 am »

Wow that is pretty compelling! I bet one of these would work well in my room.

dvenardos · « **Reply #3 on:** 12 Mar 2010, 04:18 am »

I happen to know quite a few people that are looking for replacement amps for sealed subs...

Are you going to offer this amp with the subs that form the bottom half of the V2, a poor man's OB sub?

alphaiii · « **Reply #4 on:** 12 Mar 2010, 02:15 pm »

Quote from: Danny on 12 Mar 2010, 03:32 am

Ported is no problem. You can get good extension with a -3db down point in the low 20's. However, it does require a pretty damn big port.

Or you could go with a 1.2 cubic foot sealed cabinet with one of our new amps.

This little amp does 200 watts into 4 ohms and 110 watts into 8 ohms.

The really cool thing is the output response. I had a circuit designed that would mirror image the roll off of a sealed box or open baffle design.

See my measured output:

The Red line is the measured output of the amp that I use with my Clio.

The green line is with the crossover set all the way up. The Purple line is with the crossover setting about half way up. And then the Blue line is with the crossover turned all the way down.

As you can see, with this amp, you will get a -3db in the low 20's in a small sealed box.

Here is a factory made measurement:

The Red line is with the crossover turned all the way up and the Purple line is with it turned all the way down.

Amps are in stock and cost $129 each.

Now how is that for a deal?

So the SW-12B and this amp in a 1.2cuft. sealed box gives this measured response? Is this in-room?

That's very impressive extension for a small sealed 12" and a low power amp. I assume this requires a good bit of bottom end EQ. How much does this limit the overall ouput of the sub?

And if one were to use one of the premade PE enclosures (which I believe are 1 cuft), how much low end and output do you think would be lost?

Thanks.

tryin · « **Reply #5 on:** 12 Mar 2010, 02:42 pm »

Now how is that for a deal?

Pretty darn good if you ask me! One question Danny, if I wired two SW12B's in parallel to give me a 4ohm load, will the amp be able to push it? Not looking for extreme output as long as it is nice and clean up to about 105db. Heck, I'd rather build a sealed sub in a tiny box any day.

Danny Richie · « **Reply #6 on:** 12 Mar 2010, 03:36 pm »

Quote

One question Danny, if I wired two SW12B's in parallel to give me a 4ohm load, will the amp be able to push it?

No problem. The amps were designed to drive a 4 ohm load.

Danny Richie · « **Reply #7 on:** 12 Mar 2010, 03:43 pm »

Quote

So the SW-12B and this amp in a 1.2cuft. sealed box gives this measured response? Is this in-room?

That's very impressive extension for a small sealed 12" and a low power amp. I assume this requires a good bit of bottom end EQ. How much does this limit the overall ouput of the sub?

And if one were to use one of the premade PE enclosures (which I believe are 1 cuft), how much low end and output do you think would be lost?

Thanks.

This is not the measured output of the sub. It is the measured output of the amp. In a sealed box the sub is going to be rolling off. The response of the amp is to mirror image that roll off. So the response should be fairly flat to about the upper 20's and -3db down in the mid to low 20's.

It will also kill output below 20Hz to keep the sub from seeing too much low frequency information and getting beat up. This was done primarily for subs in an open baffle, like the ones used in our new V-2 kit.

http://www.audiocircle.com/index.php?topic=71532.0

A smaller 1 cubic foot enclosure is just going to put a little more load on the amp.

alphaiii · « **Reply #8 on:** 12 Mar 2010, 04:02 pm »

Quote from: Danny on 12 Mar 2010, 03:43 pm

This is not the measured output of the sub. It is the measured output of the amp. In a sealed box the sub is going to be rolling off. The response of the amp is to mirror image that roll off. So the response should be fairly flat to about the upper 20's and -3db down in the mid to low 20's.

It will also kill output below 20Hz to keep the sub from seeing too much low frequency information and getting beat up. This was done primarily for subs in an open baffle, like the ones used in our new V-2 kit.

http://www.audiocircle.com/index.php?topic=71532.0

A smaller 1 cubic foot enclosure is just going to put a little more load on the amp.

Got ya. I must have missed the part about the mirrored roll-off in your first post.

So what would the upper limit look like? In other words, could this sub/amp be used with an AVR crossed as high as 120Hz, or does the upper end roll-off before that? It's clear the amp's output rolls off below 100Hz, but I'm not sure what the net result would look like.

Marbles · « **Reply #9 on:** 12 Mar 2010, 04:02 pm »

Why not just save a few pennies more and go Servo?

alphaiii · « **Reply #10 on:** 12 Mar 2010, 04:10 pm »

Quote from: Marbles on 12 Mar 2010, 04:02 pm

Why not just save a few pennies more and go Servo?

This sub could be built for under $400 even with a pre-built cabinet.

A servo with the basic 300W amp is quite a bit more if you need to have a cabinet built - its $400 for just amp and driver.

tryin · « **Reply #11 on:** 12 Mar 2010, 04:48 pm »

Quote from: Marbles on 12 Mar 2010, 04:02 pm

Why not just save a few pennies more and go Servo?

I guess because I'm cheap! This sub will primarily be used for tv/ movie watching and occassinal music. I'd love to have a servo but I can build a sub with 2 12" drivers and Dannys amp for less than I can buy the 370PEQ amp for. For what I'm going to be using it for, it should be awesome, much better than my ported 8" that I've been using for years.

Danny sold these subs for years with very positive reviews, my brother built one with the PR a couple years ago and I thought it was just fine for what I need.

Danny, should be giving you a call soon!

satfrat · « **Reply #12 on:** 12 Mar 2010, 05:29 pm »

What are the inlet dimensions for this subamp? Thanks.

S Clark · « **Reply #13 on:** 12 Mar 2010, 06:18 pm »

Tryin,
I have this sub with the passive radiator in a box made to Danny's specs. Powered by a 240W amp (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-804). With my LS9's starting to take shape, I don't need it. If you are interested send me a pm- I'll make it attractive to you. I have had it about 1 year, so it is broken in, yet not worn.

Scott

Danny Richie · « **Reply #14 on:** 12 Mar 2010, 07:28 pm »

Quote

What are the inlet dimensions for this subamp? Thanks.

It is 7.125" wide by 10.625" tall.

tryin · « **Reply #15 on:** 12 Mar 2010, 08:42 pm »

Quote from: S Clark on 12 Mar 2010, 06:18 pm

Tryin,
I have this sub with the passive radiator in a box made to Danny's specs. Powered by a 240W amp (http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-804). With my LS9's starting to take shape, I don't need it. If you are interested send me a pm- I'll make it attractive to you. I have had it about 1 year, so it is broken in, yet not worn.

Scott

While I do appreciate the offer, I just want to build something. I just built a pair of TriTrix's for my dad and I kind of have the bug.
Just placed an order for two subs and the mentioned amp, should be a fun project.

S Clark · « **Reply #16 on:** 12 Mar 2010, 09:23 pm »

No problem. I think you are going to be very happy with the quality of these guys. I recommend that you get a sheet of No-Rez from Danny as well and don't skimp on the internal bracing!

tryin · « **Reply #17 on:** 13 Mar 2010, 01:38 am »

Danny,
Working on the box design, I need to know how much volume to deduct for the sub and the plate amp.

So far this thing is looking like it will be about 30" tall, 14" wide and 14" deep.

oz_audio_todd · « **Reply #18 on:** 14 Mar 2010, 11:53 am »

Hey Danny,
is there any chance that u have the software to add the theoretical response of that box/driver to those shapes and sum them?
May be even a second set with the sub in a 2.5 cubic foot box (if it would make much difference?)?
Ta, Todd

Danny Richie · « **Reply #19 on:** 14 Mar 2010, 05:46 pm »

Quote

is there any chance that u have the software to add the theoretical response of that box/driver to those shapes and sum them?
May be even a second set with the sub in a 2.5 cubic foot box (if it would make much difference?)?

I can't do anything with theoretical responses, but if I build out a sub (in a box), then I can measure it.