Prebuilt subs anyone?

Brian Bunge · « **on:** 3 Sep 2003, 05:19 pm »

I've been toying with the idea of offering fully designed and assembled subs that customers can order and only have to specify the finish. In other words, this driver in this box with this amp and the customer just specifies the finish.

One design I've come up with would use a Stryke AV12, a 350W Rythmik Audio amp with an LT circuit designed to my specs and a roughly 14" cubed enclosure. Depth will be slightly greater for flush mounting the driver and adding a grill.

The design I've come up with should give you a flat in room response to 20Hz. It won't be an SPL monster, but will give you very good extension from a very small enclosure.

Introductory pricing will be $750 for natural oak, maple or cherry veneer with a semi-gloss finish.

Also, I have a design in the works using the same amp with an LT circuit and the Stryke AV15.

So you guys let me know what you think.

Marbles · « **Reply #1 on:** 3 Sep 2003, 05:27 pm »

Would these be ported, sealed, or have passive radiaters?

Any idea on the Q? Will these have a flat frequency response up to say 80 - 100 hz?

That 15" sounds very interesting, any ideas on it?

The price and size (14" cube) of the 12" sounds pretty good.

Brian Bunge · « **Reply #2 on:** 3 Sep 2003, 05:44 pm »

The inclusion of an LT circuit necessitates that the enclosure be of an acoustic suspension type. I say that instead of sealed because there are those that confuse a PR enclosure as sealed because there isn't a hole in the enclosure.

The 12" version will have a Qtc of .7 and an Fb of 20Hz.

I'll have to look at my notes on the 15" version and get back to you. I've got several ideas but since I'm using the Rythmik amp I like to bounce my ideas off of Brian Ding since he's intimately more familiar with it than I. I like to make sure there's no chance of damaging the amp with any crazy ideas I come up with!

Jason1 · « **Reply #3 on:** 3 Sep 2003, 11:32 pm »

I think a Tumult with a pair of Stryke PR18-2500's in a 250 liter enclosure would be pretty incredible. It should excell with anything you desire. Group delay numbers are very low down to about 22hz, and with an f3 of 30hz and a f6 of 12hz, in room response should be flat to 12hz. The Tumult will be able to handle those frequincies with serious output.

Thats the kind of reference bass system I would love.

Brian Bunge · « **Reply #4 on:** 4 Sep 2003, 01:27 am »

Jason,

Since I'm an Adire and Stryke dealer that would be easy enough to do. But I personally would opt for a 141L enclosure. You get better output in the range where there is more info. in music and movies. Not much reason for flat response to 12Hz unless it's for playing back test tones.

Jason1 · « **Reply #5 on:** 4 Sep 2003, 01:51 am »

But the low tune provides better group delay numbers, and flatter in room response. That yeilds superior music performance. It should still be capable of 115db

Yes a higher tune gives more output above 20hz... I just dont think its nessecary to have 130db capability. With the PR's providing much of the output in the audible range, and the much higher group delay numbers, musical accuracy will suffer.

Of course, this is all theory

Brian Bunge · « **Reply #6 on:** 4 Sep 2003, 02:18 am »

If you want musical accuracy then why are we even talking about PR's? I'd choose a sealed enclosure for such an application.

Speaking of which, here is what a customer of mine said just days ago about his dual sealed Tumults with 1400W each and an LT circuit. Fb is 18Hz and Qtc=.6.

"While it is impossible to do an A/B, the tumults easily sound as good as the
dual Aerial SW12 and Revel B15 that I have listened to-quite possibly
better. I have never heard a dual HGS-18 system, but this is clearly better
than any single HGS 18 system that I have listened to."

Jason1 · « **Reply #7 on:** 4 Sep 2003, 02:30 am »

I'm trying to come up with the perfect sub

How foolih is that

Brian Bunge · « **Reply #8 on:** 4 Sep 2003, 02:43 am »

I strongly believe there is no such thing as the perfect sub. Every design has it's compromises. Choose what is most important to you and go from there. The designs I'm proposing in this thread are relatively small subs with great musicality and pretty decent output for their size.

Brian Bunge · « **Reply #9 on:** 4 Sep 2003, 02:12 pm »

After looking at my designs again, I think I can work the AV15 into a 17" or so cube without much trouble. With the LT you'd be looking at probably a similar alignment to the AV12. Maybe slightly lower Qtc since we're talking a bigger box and I'm not looking for absolute smallest size for the AV15. I should still be able to get good extension and output down to 20Hz in room though!

Hank · « **Reply #10 on:** 5 Sep 2003, 02:16 pm »

Sounds good Brian. Also, I'd like to offer a mid-line sub that's affordable to more people. Low end, I'm not interested in - too many mass-produced in China to compete with.

Brian Bunge · « **Reply #11 on:** 5 Sep 2003, 02:21 pm »

Hank,

What do you consider midline? What I'm talking about here or slightly cheaper? BTW, I got your last 2 emails this week. I'll reply soon.

Brian Bunge · « **Reply #12 on:** 5 Sep 2003, 06:58 pm »

Of course, the first customer that ordered one of these subs had to have it downfiring

so I thought I'd share pictures of it along the various stages of completion.

You can see it in this thread:

http://www.audiocircle.com/index.php?topic=4599

MaxCast · « **Reply #13 on:** 5 Sep 2003, 08:04 pm »

Brian, have you thought about offering passive subs? If so, any idea on the price of a pair of passives?

Also, what size and driver will be used for your final design?

Brian Bunge · « **Reply #14 on:** 5 Sep 2003, 08:25 pm »

I have no problem offering passive subs. The AV12 based sub will be a 14" cube when the driver is frontfiring. That's with the LT circuit. Without the LT circuit in this enclosure heavily stuffed you'd be looking at a Qtc around .65 but with an anechoic F3 around 40Hz. The AV15 in the box I'm proposing (roughly 17.5-18.5" cubed) would give you about the same Qtc and F3.

As far as pricing, you'd be looking at about $600 each for the AV12's passive and probably around $850 each for the AV15's passive. All this is dependant on the actual finish used of course. I know materials cost isn't that much greater for the larger enclosure, but once you get above about 1.5ft^3 I like to use plenty of bracing and I also work slow so I have to cover my labor costs.

Also, these prices are based on the introductory pricing I had in mind. Expect final pricing to be around $50-$100 more.

Hank · « **Reply #15 on:** 9 Sep 2003, 06:00 pm »

Brian, by mid-line pricing, I'm talking about $400 with plate amp. Low end is the mass-produced stuff from $129 to $299 (or so).

Brian Bunge · « **Reply #16 on:** 18 Sep 2003, 02:34 pm »

Just thought I'd post about the first of the SV12/LT based subs to go out. The first customer received his yesterday and said that he was hitting 110dB peaks already in room. I don't remember what movie it was, one of the newer Bond flicks, but he seemed very pleased so far. I'm getting specifics about his room and hopefully will have him post about his impressions in a few days.

derek · « **Reply #17 on:** 19 Sep 2003, 02:04 am »

Quote from: Brian Bunge

Just thought I'd post about the first of the SV12/LT based subs to go out. The first customer received his yesterday and said that he was hitting 110dB peaks already in room. I don't remember what movie it was, one of the newer Bond flicks, but he seemed very pleased so far. I'm getting specifics about his room and hopefully will have him post about his impressions in a few days.

Hello,

I am the proud owner of this new sub. The movie was die another day on the opening scene when 007 is surfing. The sub was in a closed room about 10' x 15' x 8' (actually a conference room at work). My digital rs spl meter was about 1 meter away aimed at the sub and peaked at 110db (uncorrected). The amp gain was set at about half. The best part was when people started coming out of their offices trying to figure out why the stuff in their offices was shaking!

You could hear (and slightly feel) the sub at the end of a hallway 100' away!

I know that Brian didn't design the sub to play this loud and I don't watch movies any where near this level. But it's nice to know it can!

So far the sub sounds great. This weekend I'll calibrate it in my room and take some measurements. I'll post my these when I'm done.

The feet look much better in person than they do in the pictures. Initially I wasn't to thrilled with the feet, but they are growing on me. The sub is behind a couch and an endtable, so you can't see them anyway.

I don't need to tell those here how great Brian is to work with. All in all, I am very pleased.

Derek

Brian Bunge · « **Reply #18 on:** 19 Sep 2003, 02:09 am »

Derek,

Thanks for the kind words. One thing to note, you'll probably have to set the amp's gain control around 9:00-10:00 on the dial in order to properly calibrate the sub. My experience has been that with the gain set at half way or higher you can never get the sub out's level on the receiver low enough to actually calibrate properly.

Let me know when you get it setup in the room, calibrated, and have taken measurements from the seating position.

Jeffrey Stanton · « **Reply #19 on:** 11 Nov 2003, 07:18 pm »

Quote from: Brian Bunge

After looking at my designs again, I think I can work the AV15 into a 17" or so cube without much trouble. With the LT you'd be looking at probably a similar alignment to the AV12. Maybe slightly lower Qtc since we're talking a bigger box and I'm not looking for absolute smallest size for the AV15:D

Hey Brian:

I'll take one of those subs. Let's go passive on it as I've already got a 275 watt/channel pro amp to drive an AV-15 I already have, but it's got to go back to TC Sounds to get repaired first.

I've already got a Tumult in a 5 c.f. box with two 2200 gm PRs, so could we tune this one to cover the next octave up, tuned more for mid-bass slam effect?? Is that do-able?

One other thing...can the box be made upfiring? It's going to have to go behind a couch and I think that'd be the best way to get the sound "out".

Thanks,

Jeff Stanton