# Thank you for REW!



## Mitchco (Apr 12, 2011)

Hello,

I just wanted to say thank you for your wonderful REW measurement software. 

Many years ago I spent a small fortune on a Techcron TEF computer that performed similar measurement functions.

Recently I got back into computer audio and have been playing with Audiolense Digital Room Correction software. Works great, but I wanted to take some waterfall plots of the before and after DRC.

I looked around quite a bit and then found your software. Worked perfectly.

I was going to post a link, but I have not submitted more than 5 messages...

You can see the graphs if you head over to Computer Audiophile site, in the left hand navigation, click on Forum and then click on General and under the sticky post, "CA Personal Blog Links" look for mitchco's blog and the entry: "Hear-music-way-it-was-intended-be-reproduced-conclusion"

Again, thank you so much for your fine measurement software.

Regards, Mitch


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## mechman (Feb 8, 2007)

Welcome to the forum. Good to have you aboard! :T


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## JohnM (Apr 11, 2006)

Hello Mitch, glad you found REW useful. For those interested in reading the blog, this is the link: Mitch's blog entry. Interesting article, impressive results from Audiolense. As an aside, your soundcard response screenshots need the SPL axis shifting so that the plots are visible, soundcard cal measurements are adjusted to be 0dB at 1kHz.


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## Mitchco (Apr 12, 2011)

Hi John,

Thanks! And oops on the soundcard response screenshots. I referenced 0db and took the shots again and updated the blog post. Thanks for pointing that out.

And thanks again for the software!


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## omholt (Jun 5, 2007)

Mitcho,

You mention that the decay (waterfall) is better with Audiolense. But I really can't see any improvement in a shorter decay. Can you posts some more graphs that shows this?

Also would really like to see an ETC of each speaker before and after the use of Audiolense.


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## robbo266317 (Sep 22, 2008)

Welcome aboard.

Cheers,
Bill.


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## Mitchco (Apr 12, 2011)

omholt said:


> Mitcho,
> 
> You mention that the decay (waterfall) is better with Audiolense. But I really can't see any improvement in a shorter decay. Can you posts some more graphs that shows this?
> 
> Also would really like to see an ETC of each speaker before and after the use of Audiolense.


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Hi omholt,

Since I can't post links here, I answered your question on my blog in which JohnM has a link to my blog entry above. Click on that to get your answer.

Cheers, Mitch


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## EarlK (Jan 1, 2010)

> Mitch I'm supposing you haven't yet discovered that REW can produce custom EQ curves that can then be exported as individual wave files ( mono or stereo ) , which can also be hosted within convolvers ( like VSTHost ) for EQing duties within the front end of players ( such as Media Center ) /// similar to what AudioLense offers ( though my quick fly-past of  *AudioLense*  seemed to indicate that it has more user control within the time domain ) .

:sn:


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## Mitchco (Apr 12, 2011)

Hi Earl, I did see that REW produces custom EQ curves and no doubt does an excellent job. I have had great success with REW, but have not used that function.

Years ago I worked in a few recording studios and control rooms. One control room was a certified Live End Dead End (LEDE) outfitted with Urei 813B "time align" monitors. This speaker/room combo was the best sound I have ever heard (it should be given the cost ;-)

My goal has been to recreate that sound, without having to design/build a LEDE room. So Audiolense's "True Time Domain" portion was a requirement for me. I am very happy with the results as measured with REW's waterfall display and posted on my blog.

Cheers, Mitch


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## omholt (Jun 5, 2007)

Mitchco said:


> ---------------
> Hi omholt,
> 
> Since I can't post links here, I answered your question on my blog in which JohnM has a link to my blog entry above. Click on that to get your answer.
> ...


Thanks for the reply Mitch. Looking more closely at the waterfall I can see some improved decay, but not much. And not what you would get with physical treatment. But some improvement is better then nothing.

Yes, I'm well of aware that ETC doesn't show the general decay in the time. ETC will show the frequencies above schroeder and how they interact with the room. ETC is a very important tool in creating a LEDE room and there are specific requirements that needs to be met. Considering that you feel Audiolense has done much of what you have experienced in a certified LEDE room, it would be very interesting to see what it looks like. Your next post is the fifth. :T


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## Mitchco (Apr 12, 2011)

Bump 5


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## Mitchco (Apr 12, 2011)

Mitchco said:


> Bump 5


Hi omholt,

Just to clarify, I have no plans to add absorption in my room. If anything, I am looking for diffusion. As mentioned before, I like live rooms. I also said I wanted the most even decay, and with TDD I get it down to 20Hz. I am impressed that Audiolense can smoothen out the low frequency decay as the RT60 plots show. 

In my experience, Audiolense has produced the closest sound to a LEDE room relative to other approaches I have tried.

Here are the ETC’s. On the TTD chart, there is pre-ringing. Known issue. 

They are two very different plots. I have a good idea as to where the reflections are. I took a mirror and laser distance measure, bounced it off the ceiling, read the distance, converted it to milliseconds, looked on the chart and correlated the peak. I have most of the peaks figured out, aside from the first two, almost all are under -20db or close to it.

Comparing the two, the TDD plot has a more smoothed level and a more diffuse pattern.


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## omholt (Jun 5, 2007)

Thanks. Just in case. Did you measure the speakers separately here or together? ETC isn't valid if you measure both speakers due to cancellations.

Here's an example of one speaker and showing the first 50-60 ms. It's good to see the first 45 ms at minimum. Even late reflections can be detrimental to the sound if there's too high gain compared to its surroundings.

And about what the thread was really about. Yes, thanks for making REW. A very nice tool. :T


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## Mitchco (Apr 12, 2011)

Yes, just one speaker. Here are the expanded ETC's.


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## Mitchco (Apr 12, 2011)

Hey John,

I wanted to thank you again for REW. I used REW extensively to write an article comparing my untreated room, with acoustic treatments, and with digital room correction. 

What is novel is that I also recorded the sound of each of these using a set of in-ear binaural microphones so that people could listen to the sonic improvements themselves.

http://www.computeraudiophile.com/blogs/mitchco/importance-timbre-sound-reproduction-systems-222/

Again, thanks so much!

Cheers,

Mitch


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## JohnM (Apr 11, 2006)

Great article Mitch, looks like a lot of work went into that.


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## Barleywater (Dec 11, 2011)

Hello Mitch,

Start correction with speaker. If it has good dispersion then brain isn't boggled by room reflections.

Here is speaker that I use for general listening and may be one of the finest monitors:

http://orion.quicksytes.com/viewtopic.php?f=14&t=2254

Regards,

Andrew


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