John Sayers' Recording Studio Design Forum Archive

Hi Stuart

Very disappointing result as I used an

1. 2010 apple mac with (OS Mountain Lion)
2. REW 5.2 (mac)
3. ECM8000 which is all I have in terms of reference mic (with calibration file)
4. Analogue decibel meter
5. Zoom Recorder interface (for input into apple mac)
output via Mackie 8 buss analogue desk to Dynaudio BM6 MK2

I have tried to calibrate according to all the REW instructions and your posts.
I set my apple mac sound inputs and outputs to the max and input on interface as far as possible (without distortion).

please note that if I set the input level on my interface as high as possible I get a message from REW that the levels are to high and distortion will corrupt the readings. So to get the level of 80db, I will have to overlook the warnings from REW.

I did NOT change any settings while doing the tests of each speaker left and right and then both as
you made this perfectly clear on a previous post.

That is LOUD! You MUST be able to hear it.

Sorry, my ears heard nothing so I will do the tests again and really listen for the "mush"

However, I concede that the readings are still not correct, so
I will try my windows laptop (OS windows 10) and see what else
I can use and see if the changes makes any difference.

Any other suggestion greatly appreciated...!!!

Mike

Very disappointing result

I'm wondering if there is something wrong with the software at some point: maybe a driver conflict, or a latency issue, or something. That "mush" might not actually be there if you can't hear it. It might be some type of artifact from software stuff... You would definitely hear it if it was real. But if it is an artifact, then that brings into question all of the data. so switching to another machine is the smart thing to do.

I did NOT change any settings while doing the tests of each speaker left and right and then both as
you made this perfectly clear on a previous post.

That's very strange. Think of it this way: If the left speaker by itself is putting out 80 dB and the right speaker by itself is also putting out 80 dB, then it is impossible that the combined level of both is also 80 dB. Mathematically, it HAS to be 86 dB. It MUST be double. There's no alternative. That would be like having two bottles of water, each with exactly one liter in each bottle, but when you pour them both into a bucket together, the result is that you still have only one liter, total.... It just does not make sense.

Therefore, the "both speakers" level MUST be 6 dB higher than the left and right channels.

Are you SURE that other speaker is being turned off completely? When you do the test for the left speaker, are you physically turning off the actual power switch on the right speaker, and the light goes off, with no sound at all coming out of it?

Are you SURE that there are no routing issues with your interface? No dynamics plug-in enabled that is increasing the level?

please note that if I set the input level on my interface as high as possible I get a message from REW that the levels are to high and distortion will corrupt the readings. So to get the level of 80db, I will have to overlook the warnings from REW.

Then there's definitely a problem with the setup somewhere, 86 dB should not be too high for your system to handle. If that were the case, you'd never be able to record anything! Many, many instruments put out way more than that.

Are you sure that the input gain on the interface is set correctly?

If the speakers are putting out 86 dB, then there's no reason why that should overload the interface, or the input to REW.

I will try my windows laptop (OS windows 10) and see what else I can use and see if the changes makes any difference.

That's an excellent idea. That will help to narrow down the possibilities.

- Stuart -

Hi Stuart

Thanks mate for your input and patience.
I will try all alternatives to hopefully get all the problems sorted...!!!

thanks again

Mike