Soffit mont kit speakers?

jsshop · Post by **jsshop** » Wed Jul 16, 2003 11:03 pm

If I buy a kit speaker designed to be built into a closed (unported) cabinet, can I just skip builing the cabinet and mount the speaker components directly to the soffit box? If so this would sem like a very cost effetive way of making soffit mounted speakers.

Post by **John Sayers** » Thu Jul 17, 2003 12:16 am

That's a good question mate - I'm awaiting Barefoot's reply as much as you. I reckon you should be able to.........hey - if you can build a box for the soffit why not put your own components into it

cheers
john

barefoot · Post by **barefoot** » Thu Jul 17, 2003 5:55 am

Unfortunately, the answer is No.

Not that you can't make the soffit box double as the speaker box. You can, and this design has been used before in high end recording studios.

[John, you probably know what I'm referring to and maybe have some links? I'm thinking of that ubiquitous main monitor design with the horn in the center and the two 12" woofers above and below. Often times they even make the front wall out of poured concrete with openings to mount the drivers. I think it was a Japanese studio designer that came up with them?]

Anyhow, the problem has to do with the difference between speakers designed for flush mounting and free standing speakers. Free standing speakers, whether ported or sealed, incorporate a high shelf filter into the crossover in order to compensate for the fact that the high frequency anechoic response is 6dB higher than the low frequency response because the front speaker baffle forces the shorter wavelengths to radiate only in the forward hemisphere, while the longer wavelengths can wrap around the speaker and radiate omni directionally. If you flush mount a speaker designed to stand free, it will create a huge +6dB response shelf below about 400-700Hz, depending on the size of the speaker baffle.

There are no kits available (that I am aware of) that are designed for flush mounting. However, I do have just such a DIY design in the works and I'm going to post it on this forum in the near future. It's going to have to wait a couple months, however, because I'm currently finalizing the design of my own monitors which will be the first offering of my new busness. If you can wait that long, the DIY project is going to be a pretty cool little monitor - dual 6.5" ported drivers and a 1" soft dome tweeter in an MTM array. I estimate the parts will cost about $300-$400.

Thomas

Eric Best · Post by **Eric Best** » Tue Jul 22, 2003 9:57 am

Thomas,

The idea of this design excites me very much!!!!!! I am waiting with great anticipation.

Eric

jsshop · Post by **jsshop** » Thu Jul 24, 2003 3:22 am

So are you aware of any crossovers I can pick up or build that dont have that shelf? I assume that is part of what you will deal with on you DIY. What price do you think your speakers will go for (not the DIY?

barefoot · Post by **barefoot** » Thu Jul 24, 2003 6:54 am

An off-the-shelf crossover actually would not contain such a filter. But any speaker built with an off-the-shelf crossover would not at all be suited for recording monitoring. Even the lowliest little $149.95/pr monitor will have a crossover that is designed specifically for its drivers.

At least in most passive speakers, there isn't really even a dedicate shelf filter. Typically the woofer response is tailored with a multi slope hi pass filter, creating both the shelf and the low pass side of the crossover. Loudspeaker CAD software is an absolute necessity in developing these circuits - unless you want to spend hundreds of hours in trial and error.

Pricing for my monitors is still somewhat up in the air. It depends heavily on whether I sell them through retailers or only direct. At this point I estimate the direct price to be approximately $1900 each.

Thomas

jsshop · Post by **jsshop** » Thu Jul 24, 2003 9:53 pm

So why does soffit mounting regular monitors work - from what you said I would thing there would be the same problem when you mount regular monitors. I read in this site and others about people mounting Mackies, 20/20's etc - would they not have the same filter problem?

barefoot · Post by **barefoot** » Fri Jul 25, 2003 2:40 am

Well, the Mackies do have an "acoustic space" selector which could possibly work for this application. Still, you have the big issue that they have a rear mounted passive radiator. As for most other nearfields..... well I'm glad that people are happy with their soffit mounted "20/20's, etc."...... but I seriously doubt these installations would fair well under the objective scrutiny of a test microphone.

Thomas

Xspringe · Post by **Xspringe** » Sun Jul 27, 2003 11:13 am

barefoot wrote:Well, the Mackies do have an "acoustic space" selector which could possibly work for this application. Still, you have the big issue that they have a rear mounted passive radiator. As for most other nearfields..... well I'm glad that people are happy with their soffit mounted "20/20's, etc."...... but I seriously doubt these installations would fair well under the objective scrutiny of a test microphone.

Thomas

So basically you are saying that soffit mounting is a bad thing when using nearfields?

...oh...btw: hi everyone

barefoot · Post by **barefoot** » Tue Jul 29, 2003 2:44 am

Yes and no.

For unmodified nearfields, yes, I think flush mounting is a bad thing. However, with the addition of a simple shelf filter to flatten the power response, I think soffit mounting is a good thing.

Ideally, of course, the speakers should be specifically designed for flush mounting. The extra filter in the signal path isn't great. And flush mounting presents a somewhat different acoustic load to the woofer and port, which in tern will mildly misalign the bass response of a speaker intended to free stand. None the less, the positives will almost always outweigh the negatives and modifying a nearfield for flush mounting is a good idea.

Rear ported nearfields? This tips the scale back to the other side, and it's prpoably best to leave the free standing.

Thomas

Xspringe · Post by **Xspringe** » Tue Jul 29, 2003 8:22 am

barefoot wrote:Yes and no.

For unmodified nearfields, yes, I think flush mounting is a bad thing. However, with the addition of a simple shelf filter to flatten the power response, I think soffit mounting is a good thing.

Ideally, of course, the speakers should be specifically designed for flush mounting. The extra filter in the signal path isn't great. And flush mounting presents a somewhat different acoustic load to the woofer and port, which in tern will mildly misalign the bass response of a speaker intended to free stand. None the less, the positives will almost always outweigh the negatives and modifying a nearfield for flush mounting is a good idea.

Rear ported nearfields? This tips the scale back to the other side, and it's prpoably best to leave the free standing.

Thomas

What about making sure that the area that holds the soffit mounted speaker is of such proportions that it does not influence accoustics as much? Like this: http://www.dikkechill.com/xspringe/boven.gif but with a larger area around the speaker?

Xspringe · Post by **Xspringe** » Tue Aug 12, 2003 4:24 am

Xspringe wrote:
barefoot wrote:Yes and no.

For unmodified nearfields, yes, I think flush mounting is a bad thing. However, with the addition of a simple shelf filter to flatten the power response, I think soffit mounting is a good thing.

Ideally, of course, the speakers should be specifically designed for flush mounting. The extra filter in the signal path isn't great. And flush mounting presents a somewhat different acoustic load to the woofer and port, which in tern will mildly misalign the bass response of a speaker intended to free stand. None the less, the positives will almost always outweigh the negatives and modifying a nearfield for flush mounting is a good idea.

Rear ported nearfields? This tips the scale back to the other side, and it's prpoably best to leave the free standing.

Thomas
What about making sure that the area that holds the soffit mounted speaker is of such proportions that it does not influence accoustics as much? Like this: http://www.dikkechill.com/xspringe/boven.gif but with a larger area around the speaker?

And maybe add some basstraps and general absorbing material in that area?