John Sayers' Recording Studio Design Forum Archive

I still haven't decided if it is the room, the speakers, or both.

It is so nice to have an isolated control room and actually hear what the drums are going to sound like before playing back!

One of these days I will do a final room measurement like I promised Stuart!

Bhudie wrote:Hey Eric,

First off, this is a very inspiring thread. Room looks great!!! I'm starting a build of my own in my new house reno, and this thread definitely piqued my interest as I'm currently trying to figure out the details of flush mounting my Dynaudio BM6As, but the DIYer in me thinks that this would be way cooler.

Not hijacking this thread for my purposes, just looking to understand this a bit better, as I know little to nothing about speaker design.

If I am understanding this correctly, you get such a good result with this method because you have a custom built crossover that is designed specifically for that room? I guess my question is if I copied your crossover design with the same exact speakers but in the room I build, would I get a poor result?

Bhudie wrote:Or is the magic in the fact that you can hand select the drivers and then ensure a custom crossover gives you a very smooth frequency response curve? That coupled with how you finished out the job very meticulously taking care of the room treatment to ensure a great sounding room?

(ps. sorry for digging up an older thread)

Thanks,
Aaron

Eric Best wrote:This forum hasn't been active for a while. I have been away for about 5 years with the speakerbuilding crowd at the parts-express forum. There I have learned quite about speaker design, and designed and built a few of my own. There is some incredible software available for free to design phase coherent flat speakers (if that is what you want).

Most of the designs that people do include flush mount speakers. The problem is that most speakers are not designed to be flush mounted because the crossovers have what is called "baffle step compensation" designed into them. This is a 6db increase built into the crossover at a frequency determined by the width of the baffle. Barefoot designed a filter to compensate for this when a speaker is flush mounted.

I found that there are a lot of people DIYing a lot of very good speakers so I decided to take the plunge. I have now decided that the way for me to go, is to measure the drivers after they are in their baffles and mounted in the wall of the studio. There is very accurate software to do the simulations of how the different speakers will work together.

These are the drivers that I am using.

2 Dayton RS225s-8 [SPAM LINK REMOVED - SPAMMER BANNED]
[SPAM LINK REMOVED - SPAMMER BANNED]
2 Tang Band W4-1337 [SPAM LINK REMOVED - SPAMMER BANNED]
1 SB-Acoustics SB29RDC-C000-4 Ring Dome tweeter [SPAM LINK REMOVED - SPAMMER BANNED]

These speakers all match very well together. The system has an efficiency of 93dB it is flat to 1.5db from 40hz to 20khz. There is no padding in the crossover design! (some of the filters have done a little padding). This design is based on the manufactures frequency response graphs (except the midranges which were done by a very respected speaker designer).
The low end is simulated based on T/S parameters.

If you want to know how some typical studio monitors measure, you can go here for a reference.
http://www.gearslutz.com/board/low-end- ... nelec.html

Here are my simulated graphs.


Here is one that has a 1dB scale

zoomed response.JPG

Here is one that shows the crossover response, the phase correlation and the nulls caused by a revers polarity that shows how well the phase tracks on the speakers.

response with phase and nulls.JPG

This is the crossover schematic.

Crossover schematic.JPG

Since the manufacturer's testing is done on an "infinite baffle" the measurements will hopefully match fairly well with what I end up with when I measure. But at least now I know well that these drivers will play well together.