Frequency Response Graph

[MartinT]

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.

[jonners]

Martin -

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

John

[MartinT]

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]

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]

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]

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]

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]

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]

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]

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.