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MartinT
28-11-2008, 09:01
I've just made my first measurements of the system in my new room with the new speakers and full room treatment. The result pretty much reflects the sound I'm getting which in frequency terms is smooth with no noticeable room nodes. This is the flattest curve I've yet achieved given that it's a real room (thus the bass hump) - from mid-bass to low treble it's amazingly flat compared with previous systems.

http://www.mtc.nildram.co.uk/graph.htm

Has anyone else tried using an SPL meter and test CD to plot their system's response? I'd be intrigued to see other findings.

Equipment used: Radio Shack digital SPL meter, Sheffield Lab D2B test CD, 1/3 octave pink noise test tones.

http://s560.photobucket.com/albums/ss49/aos_images/random_stuff/graphr.jpg

jonners
28-11-2008, 09:42
Martin -

I wonder if you have seen this article, which looks at the accuracy of the Radio Shack meters: http://www.audioxpress.com/magsdirx/ax/addenda/media/koya2811.pdf

John

MartinT
28-11-2008, 10:32
Eek - not so impressive. Ok, so on an absolute scale my readings may be out, but comparatively this is still the flattest response I've had and much smoother than my previous JM Lab Mezzo Utopia speakers. My low frequency room node is at 40Hz, just as with one room mentioned in the article. I guess anyone else with the RS digital meter could compare curves with mine. It certainly explains the apparent premature roll-off at the treble end, not what I expected with the beryllium tweeter.

Primalsea
07-12-2008, 14:31
Hi Martin,

I took some room measurements a while with my last speakers, haven't done it with the latest ones though. I used a program called ARTA which is very acurate. You will also need an acurate mic capsule. I used a Panasonic WM61 that I taped to the end of an alu tube.

If you're interested I can email you the progarm and if you want the mic capsule I might have a spare one that you can have for a nominal sum or maybe a CD or record or something low value but of interest.

PM me if you're interested

MartinT
10-12-2008, 10:26
Hi Paul
I will be away for a while but I might experiment with this sometime early next year. Thanks for the offer of the software, I'll probably take you up on it. Despite the RS meter not being too accurate, it has allowed me to compare what I have now (room & speakers) with what I had before and I can see, as well as hear, the improvement.

Steve H
04-03-2009, 19:02
Martin, this may be long after interest has waned but, in case not: Rives Audio produce a test CD (their Test CD 2) which has two sets of tones, one corrected for the RS SPL meter.

url is www.rivesaudio.com

Steve

Clive
04-03-2009, 19:37
Using DSP I get an in-room response of +/- 3db in the bass. The 30Hz room mode in original post is typical and quite severe.

MartinT
09-03-2009, 20:59
Steve - thanks for that info. The good news is that I am satisfied with my room treatment and am greatly enjoying listening to music. No more measurements for now!

Spectral Morn
09-03-2009, 23:09
Hi MartinT


Nice to see you posting again. I have missed your contributions over the last few weeks.



Regards D S D L---Neil :)

MartinT
09-03-2009, 23:21
Hi Neil

I've been undergoing chemotherapy after surgery and am now on the road to recovery and even back at work full time. I'm back into forums and will try to post more regularly from now on.
I have to say that music has done a lot to lift my spirits and keep me going during dark moments.

Spectral Morn
09-03-2009, 23:23
Hi MartinT


Really sorry to hear that, heres to a full and speedy recovery. I have missed you and I am glad you are back.

I know what you mean about music....indeed it can be a light shinning in the darkness of extreme difficulty. Music can lift your spirit like very little I know and quite quickly... Its is this sort of thing which makes it hard for me to understand why many just don't get it or want to get it. They must have hearts of stone....


Regards D S D L---Neil :):)

MartinT
10-03-2009, 08:05
Thanks Neil, I'm certainly glad to be back and enjoying life. Music is indeed the only drug I really need.