diy soffit mounted speakers

jdean · Post by **jdean** » Mon Sep 15, 2003 1:31 am

barefoot

a feww months ago i read that you had been working on plans for soffit mounted MTM monitors. i know your busy, but i will be framing the wall my monitor wall in the next 2-3 weeks and am wondering if you are still working on this design and , if so, do you have an estimate of the dimensions and proper mounting height.?

thanks for all you do around here.

barefoot · Post by **barefoot** » Tue Sep 16, 2003 3:21 am

Welcome to the forum!:D

My initial estimates of the dimensions are 30"x10"x13" (HxWxD). This would be a tall narrow box housing two 6.5" woofers and a 1" dome tweeter. The tweeter would be vertically and horizontally centered in the cabinet.

The tall narrow dimensions simplify box bracing and construction. I don't see a big problem soffit mounting a box like this, but maybe you or someone else does? The dimensions could go something more like 22"x14"x13" (HxWxD) if needed?

Thomas

jdean · Post by **jdean** » Wed Sep 17, 2003 8:57 am

thank you. i don't see any problem withe the dimensions for stereo but...

is the orientation critical? i was thinking of putting in a soffit for a center channel in case i ever go to surround. the height of the speaker would make it difficult to place the window to the tracking room unless i could mount it horizontally.

Paul-Doug · Post by **Paul-Doug** » Wed Sep 17, 2003 12:06 pm

A DIY soffit mounted monitor design would be great but - and pardon my naive question here because I know nothing about speaker design - is it possible to get good bass response from 6.5" woofers?

Thanks,

Paul

giles117 · Post by **giles117** » Wed Sep 17, 2003 3:54 pm

Keep in Mind barefoot is designing a dual 6.5" Box. Bass response is a combination of driver size and volume of air pushed whereas speaker design is concerned.

I would expect a nice amount of bass as you are pushing more air volume than say a single 8" or 10" Driver.

Bryan Giles

This is an oversimplistic illustration.

Thomas How goes the time table?

Looking forward to the units.

Eric Best · Post by **Eric Best** » Thu Sep 18, 2003 12:20 am

My main monitor is a dual 6.5 design and there is no problem with bass. I have a subwoofer with it, but I usually don't even turn it on. Using a dual woofer that is smaller you get more detail and still get the baass response.

Paul-Doug · Post by **Paul-Doug** » Thu Sep 18, 2003 2:16 am

Excellent!

Can't wait to see the plans!

barefoot · Post by **barefoot** » Thu Sep 18, 2003 4:36 am

I prefer to build active 3-way systems using 5" woofers. 5" is the size were you find drivers with the very best midbass and midrange performance. Of course, active systems don't lend themselves to DIY. And 5" drivers don't produce a lot of bass in a 2-way system. 8" drivers provide reasonable bass, but they are simply too big to produce truly high performance midrange. So, 6.5" woofers are a good a compromise. Two 6.5" woofers have slightly more surface area than a single 8" driver, plus superior midrange (assuming equivalent quality). The symmetric geometry also has advantages with respect to vertical polar response.

jdean,

For best performance I highly recommend that you keep the speakers vertically aligned. Horizontal alignment yields a very narrow listening area.

As long as you maintain the same tuning, the box dimensions are somewhat malleable. We can come up with a low profile design for your center channel. However, I really prefer to keep the speaker axis closer to ear level. It sounds more natural, and it also helps reduce reflection and diffraction problems from the mixing board or workstation.

How about this somewhat novel idea?..... What if you built a tall, narrow speaker box and mounted it in the middle of a split control room window... like I've illustrated below?

Thomas

barefoot · Post by **barefoot** » Thu Sep 18, 2003 6:41 am

Just updated the image to make the design clearer. Click your browser refresh if you already looked at my previous post and can't see the newer image.

Thomas

giles117 · Post by **giles117** » Sat Sep 20, 2003 10:11 pm

Whichever one you do, I am looking forward to it, what kind of HF driver will you be using? Ribbon? Titianium? what?

Bryan Giles

Your comments about the midrange accuracy are the main reasons I was looking at the KH O300d.

Not to mention are they a sealed box design.

For anyone, here is a refresher.....

http://klein-hummel.com/e/produkte/o300 ... 300d_e.htm

I'd love something proprietary though, no copy catters. So Hurry up Thomas, my wallet is growing. LOL

My Mastering engineer uses these and boy do they tell the truth about my mixes. I of times go home in shame, to remix because the detail is soooooo accurate. Good thing he is only 30 minutes away.

barefoot · Post by **barefoot** » Sun Sep 21, 2003 12:18 pm

Bryan,

I want to keep the first projects affordable and also use widely available parts. Likewise, they need to be relatively simple, so a sophisticated active bass managed design like 0300d is out.

The drivers I have in mind are the venerable Vifa P17WJ-00-08 woofer in a ported box and the Vifa DX25TG05-04 tweeter.
http://www.d-s-t.com/vifa/data/p17wj-00-08a.htm
http://www.d-s-t.com/vifa/data/dx25tg05-04a.htm

These drivers will give very good performance for a reasonable price (~ $400 US pair). The speaker will also be fairly high efficiency to help deliver some of that main monitor impact in smaller studios.

Timeline? I can't say. I'm still working intensely on the Mini Main™ 12 development. That has to take first priority.

Thomas

Jon Best · Post by **Jon Best** » Fri Dec 05, 2003 12:39 pm

Well, isn't that just weird. I was thinking of whacking together some 2-ways to play with, and a little poking around has that same tweeter going in between a couple of Vifa TC18SG49's as an MTM. Closed box, that's why the different woofers, and probably active, with a decent Rane or Ashly crossover, an old Yamaha P2100 for the bottom, and an Adcom 535 on top.

barefoot wrote:Bryan,

The drivers I have in mind are the venerable Vifa P17WJ-00-08 woofer in a ported box and the Vifa DX25TG05-04 tweeter.
http://www.d-s-t.com/vifa/data/p17wj-00-08a.htm
http://www.d-s-t.com/vifa/data/dx25tg05-04a.htm

These drivers will give very good performance for a reasonable price (~ $400 US pair). The speaker will also be fairly high efficiency to help deliver some of that main monitor impact in smaller studios.

Thomas