Recent content by Keith_W

1. Every speaker and subwoofer should be measured individually with a timing reference for initial tuning. 2. If you have two subwoofers sharing a DAC channel, measure each sub individually then tune them with the phase/polarity/SPL controls at the back until they blend properly. From then on...

Assuming this is not a typo and you actually mean 80 MICRO seconds (and not 80 milliseconds). 80us in which measurement? If the peak is in the L+R measurement and not in the individual measurements, then it's a non-centred microphone. If it's 80us in an individual speaker measurement (i.e. it...

From a faulty microphone perhaps? Should we advise the OP to try another USB microphone?

All right, I definitely can not figure this one out. Hopefully @John Mulcahy or someone smarter will have a suggestion. This is the problem: Here are 5 measurements of your right speaker. You can see that there are clearly two types of impulse response. One predominantly upgoing (positive...

I decided some time ago not to respond to any more of your posts because my patience ran out much earlier than John's. You don't seem to learn and you are asking the same question over and over, but in a different form. 1. Please read John's post here as many times as you need until you...

Oh boy, what a head scratcher. I don't think I can figure this one out. First we look at your frequency response graphs. Here are three measurements of your left speaker. They are mostly the same. Now we evaluate measurement quality by looking at the waterfall and extending the time...

Good work on your latest set of measurements, it looks as if you have learnt a lot. Keep it up! If you are using your mic at 90 degrees, as you said you are, it seems unlikely to be due to the microphone stand although I guess it could still be possible. It is also possible that it is an...

ASR DIY microphone calibration.

Please understand what I am trying to tell you: RT60 is meaningless at low frequencies in small room acoustics. The reasons are: 1. There are no reverberant fields, there are room modes. Even at high frequencies, reverberant fields may or may not exist. There are specular reflections. Toole...

You should be able to answer your own questions by reading that eBook. Re: the ETC peaks, read the section on ETC to see what they mean, determine whether they are a problem, and how to work out what is causing the peak. As for your other measurements, here is something rather interesting...

I don't have a lot of time right now, but i'll answer this question first. The answer is: measurement artefact from an improperly centred microphone. This is the proof: This is a comparison of the vector sum of L+R ("before treatment") in purple, and the actual measurement in red. We can see...

One glance at your RT60 chart and it is easy to see that you have WAY OVERTREATED your room, look at that - the RT60 at high frequencies is 150ms or less. At times it's less than 20ms. It would sound close to an anechoic chamber. And if you are not used to those numbers, it should be about 200ms...

That ETC looks excellent, I don't think you have much to complain about. If you want a better idea what your bass is doing, use the spectro and waterfall. The spectro needs to be "normalized to peak at each frequency" to give you an idea of bass decay. The waterfall should be extended to...

Please think a bit about what the Clarity measurement is. It has nothing to do with subjective clarity. I think it is the most useless measurement, and I can't think of any application for it. How REW calculates clarity C50: the first 50ms of the impulse is expressed as a % of total energy...

Correct, I align all the drivers on the left speaker to the left tweeter. That makes sense to me :) A 4th order LR can be either linphase or minphase. If you are using linphase, then the 90deg phase rotation per order does not exist. All symmetrical filters of whatever order will sum...