Voxel - a mini-sub+

[tomzarbo]

I posted a revised drawing for the Voxel with the 70 watt amp for another member a while back. Here's the link: http://techtalk.parts-express.com/fo...i-go-from-here

Look at post #17 in the thread for the details. Hope it helps, good luck!

Yikes, I forgot about that, I do remember seeing that awhile back. Nice!
TomZ

[Millstonemike]

Yes, the revised version was still built from 1/2". Robert (Woodsart) built this version and would be better suited to answer your question on the stability of the sidewall after cutting the amp plate hole. I would think it would be ok since the plate is pretty beefy and once screwed into the wall should shore it back up pretty good. You could build it from 3/4" if you don't mind the additional 1/2" of length, width, and height. Just keep in mind all of the dimensions on the drawing will have to be adjusted for the additional 1/4" of material. Good Luck!

Or you could just use 3/4" MDF on the plate amp side ... perhaps on the woofer side as well.

[Kevin K.]

Thanks Kevin! That looks a lot like the thoughts bouncing around my head. Glad to see someone's considered this before and that I'm not nuts! I couldn't tell from the post (maybe I missed it) but does your version still use 1/2" thick material? I was considering the 3/4" MDF approach for this one just to make sure there weren't any concerns with structure after cutting a big hole for the plate amp.

Yes, the revised version was still built from 1/2". Robert (Woodsart) built this version and would be better suited to answer your question on the stability of the sidewall after cutting the amp plate hole. I would think it would be ok since the plate is pretty beefy and once screwed into the wall should shore it back up pretty good. You could build it from 3/4" if you don't mind the additional 1/2" of length, width, and height. Just keep in mind all of the dimensions on the drawing will have to be adjusted for the additional 1/4" of material. Good Luck!

[Paul Carmody]

http://techtalk.parts-express.com/forum/tech-talk-forum/67644-sa70-where-do-i-go-from-here?p=1087402#post1087402

Kevin pretty much nailed it there.

[KEtheredge87]

I posted a revised drawing for the Voxel with the 70 watt amp for another member a while back. Here's the link: http://techtalk.parts-express.com/fo...i-go-from-here

Look at post #17 in the thread for the details. Hope it helps, good luck!

Thanks Kevin! That looks a lot like the thoughts bouncing around my head. Glad to see someone's considered this before and that I'm not nuts! I couldn't tell from the post (maybe I missed it) but does your version still use 1/2" thick material? I was considering the 3/4" MDF approach for this one just to make sure there weren't any concerns with structure after cutting a big hole for the plate amp.

[Kevin K.]

Solid points, Tom! Going with the 70W amp feels like the better choice for a build that I'm gifting just on the whistling possibility and auto-detect signal features alone. That choice is forcing me to expand the original box design to accomodate the lost volume... not to mention having a section of cabinet large enough to mount the amp. I've never modeled a cabinet in winISD or anything else before... as long as I match the inside volume to Paul's original design, will I be ok? I don't plan to change port length or anything, but I may go down-firing to alleviate any "accidental contact with the driver" concerns.

As always, thanks for the help!

I posted a revised drawing for the Voxel with the 70 watt amp for another member a while back. Here's the link: http://techtalk.parts-express.com/fo...i-go-from-here

Look at post #17 in the thread for the details. Hope it helps, good luck!

[tomzarbo]

The big thing is to keep the interior volume the same, right. Per the product page: Dimensions: 7-1/2" W x 8-11/16" H x 3-1/2" D • Enclosure cutout: 6-5/8" W x 7-3/4" H ...So I'd add enough volume for those dimensions of the inner case... approx. 3" deep, 6.5" wide, by 7.5" tall..... and add that to the volume of the box, you should be fine.

I've built a Voxel and it makes me laugh when I see how much bass comes from that tiny little thing. It's crazy!

TomZ

[KEtheredge87]

I agree with Mike about going bigger if you can easily do so.

Thing with the 25 watt plate amp is that it has no inner "case" to surround the electronics. That's good because it basically takes up no cabinet volume in 3/4" material. But, it can whistle through the jacks on the plate if it's not sealed up properly -- I've had this happen on 4 of those amps purchased in the past year.
But, the 70 watt amp does have a plastic inner case that will eat up some of the volume of the box, you need to figure out how much and subtract that from your box size.

In my sims of the 5 1/4" TB sub with two PR's in Wolf's "Triumph" design, as well as my own "buyout" PR sub cube, the difference in output from 25 watts to 40 watts was only a few dB, and didn't warrant the extra expense of the bigger amp on output alone. Of course, headroom is nice to have and the 70 watt unit will auto-detect a signal where the 25 watt unit won't.

TomZ

Solid points, Tom! Going with the 70W amp feels like the better choice for a build that I'm gifting just on the whistling possibility and auto-detect signal features alone. That choice is forcing me to expand the original box design to accomodate the lost volume... not to mention having a section of cabinet large enough to mount the amp. I've never modeled a cabinet in winISD or anything else before... as long as I match the inside volume to Paul's original design, will I be ok? I don't plan to change port length or anything, but I may go down-firing to alleviate any "accidental contact with the driver" concerns.

As always, thanks for the help!

[tomzarbo]

I agree with Mike about going bigger if you can easily do so.

Thing with the 25 watt plate amp is that it has no inner "case" to surround the electronics. That's good because it basically takes up no cabinet volume in 3/4" material. But, it can whistle through the jacks on the plate if it's not sealed up properly -- I've had this happen on 4 of those amps purchased in the past year.
But, the 70 watt amp does have a plastic inner case that will eat up some of the volume of the box, you need to figure out how much and subtract that from your box size.

In my sims of the 5 1/4" TB sub with two PR's in Wolf's "Triumph" design, as well as my own "buyout" PR sub cube, the difference in output from 25 watts to 40 watts was only a few dB, and didn't warrant the extra expense of the bigger amp on output alone. Of course, headroom is nice to have and the 70 watt unit will auto-detect a signal where the 25 watt unit won't.

TomZ

[Millstonemike]

Hi Everyone,

I'm in the early stages of considering the Voxel design to go with a 5 channel setup of Scott Sehlin's Heliums. I am a bit confused on the subwoofer amp topic. Can anyone provide a bit more experience on the plate amplifers? While the Dayton Audio 25W plate amp will fit the original enclosure better, I am wondering if the 70W plate amp may be a better choice to drive the tang band woofer since so many have commented that the woofer acts like it can use more power.

25W amp: http://www.parts-express.com/dayton-...ProductDetails
70W amp: http://www.parts-express.com/dayton-...ifier--300-784

Thanks in advance!

If the larger amp will physically fit in the box, it's a better amp for the sub. The Woofer is fairly inefficient and is good to 40w so the 25w amp is under powered. And it's always good to have extra watts, headroom, on the amp. Just be cognizant of distortion when using higher power levels.

[KEtheredge87]

Hi Everyone,

I'm in the early stages of considering the Voxel design to go with a 5 channel setup of Scott Sehlin's Heliums. I am a bit confused on the subwoofer amp topic. Can anyone provide a bit more experience on the plate amplifers? While the Dayton Audio 25W plate amp will fit the original enclosure better, I am wondering if the 70W plate amp may be a better choice to drive the tang band woofer since so many have commented that the woofer acts like it can use more power.

25W amp: http://www.parts-express.com/dayton-...ProductDetails
70W amp: http://www.parts-express.com/dayton-...ifier--300-784

Thanks in advance!

[Paul Carmody]

Yes, this is based on my T/S measurements of the actual driver.

[Chris Roemer]

Paul might have actually measured his "in-hand" driver, but using the mfr's specs (Qts=0.49, Vas=0.17cf, and Fs=45Hz) a 7L box tuned in the lower 40s yields an F3 in the high 30s.

[barrymossel]

I really love this small subwoofer and probably will build it myself. But when I put this in WinISD i get an F3 of something more like 40Hz. Not that should be a problem, but I was wondering if I did something wrong (either in WinISD or the conversion of the dimensions to the metric system).

Might anyone shed a light on this?

[Paul Carmody]

thankyou for the respond Paul,
my original plan was using something like gordy use in madeleine (see picture)
i was looking around for sure amp but cannot find one for 4.1 system.
i will consider your sugestion and look for budget receiver, if i cannot find one good budget receiver than i will go with voxel + ONS

My favorite way to shop for receivers is from people who have upgrade-itis, and sell ones that have last-generation's features for pennies on the dollar. Also, places like accessories4less is excellent for refurb MidFi equipment.