rta tools for everyman

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perhaps you've all seen these but i'll put 'em in one place for ya.

first up: third octave signal source. you do own a cd player? :clown:

http://www.rivesaudio.com/software/TestCD.html

second: microphone/meter combo.

http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=33-4050

third: a hunka hunka graph paper, if you prefer semi-log to the stuff they have on the rivesaudio website for dl. i do. it makes my graph look like one of those fancy printouts, and gives my little elbow-grease measurements an air of authority:judge:

http://www.tubesville.com/audiograph.JPG

you supply the pencil.

never give away drivers to see these somewhat useful measurements again. please remember to trust ears, instincts, and sense of fabulousness above all, my dahlings.

wanna model some BSC filters or something? oh, ok.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=41278

i'd hold off on getting the better soundcard for now, since a new version of the software is coming soon (haha) with some hipper soundcard compatibilites. this one is working for me:

http://www.jr.com/JRProductPage.process?Product=2013347

i'm hoping the new version of the software will do 1st order above 8k. meanwhile, the current version is quite useful for some things (see thread and driver forum).

ps. i have no affiliation with any of the above, commercial or non-commercial.
 
music soothes the savage beast
Joined 2004
Paid Member
to make things right, those are not mine modifications!
i just applied them
i have both, analog and digital spl meter
they in their commercial form are terrible on bass accuracy,
rolloffs due to lousy capacitor choices
both can be improved dramaticaly for capsule is practicaly flat
when it comes to the hights, analog is better and goes further due to better electronics
digital wil never go all the way up due to poor electronics
after modification they are both very accurate for most critical 300-3000

btw i use behringer ECM 8000 reference condenser with behringer ultra curve for extremely precise measurement

but at the end i do tailor the eq curve to my likeing anyway
 
adason said:
to make things right, those are not mine modifications!
i just applied them

btw i use behringer ECM 8000 reference condenser with behringer ultra curve for extremely precise measurement

but at the end i do tailor the eq curve to my likeing anyway

yes, i remember seeing those posted on the lsdg or joelist a way back when. still good today.

the behringer setup is great, and under $500. also the ULTRADRIVE PRO DCX2496 for crossover purposes...does all ya need! then you're up around US$1000 total...

i would say the system i listed is the $100 version of the behringer. naturally less convenient, steeper learning curve, less flexible, "fudgier" and less accurate. but...

...in the end we tailor to preferences one way or the other. :)
 
Re: speaker work shop

tenderland said:
Could you use Speaker Workshop for RTA , with a lap top ,
and what sound card could you use ?
Jeff

hey mateys

i'm just suggesting one very simple, adequate solution among many.

a $40 measuring device with a funky but reproducible and predictable curve, and a $21 CD that is designed to work with it, a piece of paper and a pencil.

plug'n'play.

honestly, i could buy any measuring system i want if i thought flat FR really mattered that much in the scheme of things...but i've tweaked too many gold-plated sales pitches with AWESOME SPECS that ate my eardrums out to fall for that 'ol line :)

any variations, you try 'em and tell ME. :)
 
Radio Shack 33-2050 and 33-4050

noisenyc said:


adason said:

I compared the two Radio Shack manuals for the 33-2050 and 33-4050 and the curves are the same. So either SPL meter should be good.

However, the CD is pretty light on frequency tracks, especially ones over 2.5kHz.

I imagine there must be some sort of tone generation software that would let you do the same thing.

Gio.
 
Re: Radio Shack 33-2050 and 33-4050

gmilitano said:





I compared the two Radio Shack manuals for the 33-2050 and 33-4050 and the curves are the same. So either SPL meter should be good.

However, the CD is pretty light on frequency tracks, especially ones over 2.5kHz.

I imagine there must be some sort of tone generation software that would let you do the same thing.

Gio.

hehe

it's third octave across the audible bandwidth 20hz to 20khz...same centers as any RTA...note the rat shack compensation curves are the same centers...3rd octave

when you figure out the response of the radio shack meter at additional frequencies, please...share the info!
 
Re: Radio Shack 33-2050 and 33-4050

noisenyc said:

it's third octave across the audible bandwidth 20hz to 20khz...same centers as any RTA...note the rat shack compensation curves are the same centers...3rd octave

when you figure out the response of the radio shack meter at additional frequencies, please...share the info!

Well, that really was not the point I was trying to make. Given the limited number of frequencies, and since you already need paper and a pen, the same could be easily accomplished with free frequency generation software and the correction table.

With regards to additional frequencies, what do programs like speaker workshop do with the calibration file? Does it just interpolate between the calibration points?

Cheers,
Gio.
 
Re: Re: Radio Shack 33-2050 and 33-4050

gmilitano said:


Well, that really was not the point I was trying to make. Given the limited number of frequencies, and since you already need paper and a pen, the same could be easily accomplished with free frequency generation software and the correction table.

With regards to additional frequencies, what do programs like speaker workshop do with the calibration file? Does it just interpolate between the calibration points?

Cheers,
Gio.

my point was this: the only thing you can accomplish with the correction table is third octave centers, which you already have on the cd,

the frequency centers are identical on the cd and correction table.

you would need to make a new correction table. which would require comparing the results at different frequency centers of the rat shack meter and a flatter system.

but then if you had a flatter system you could just measure...the speaker :)
 
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