RTA or Not to RTA... Thats the Question!

[Ht4me]

WANT TO DO MORE TO IMPROVE THE EXPERIENCE!

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...I'm nnnot adddicted to ht, am I?

How about some assistance on RTA's... I've got Rives CD to use with my digital spl (if I ever will just do it).

A) Not for the weak . . . But worth the trouble.
B) Oh, you gotta do this! ! ! !
C) O.M.G. , I can't believe you said your a ht enthusist and haven't done it already. . .
D) forget it, for now , you need to do 1,2,3,4 etc. first
E) ???????????? (fill in the Blank)
F) whose do you use, behringer, rane, dod, etc.??

G) or just sit down, shut up, pass the popcorn & watch the #@!& movie.

this may not be at all the correct place to start such a question, sorry...I'm bummed out as my new dlp went to the shop for a light engine & color wheel combo fix
so....
oh, just started lookin' in Cedar Creek Cinema....oh dat's nice! ! ! !

Mike

[AverageJoe]

Hi Mike,

No expert advice from me, since I still haven't finished putting all the components together to do any "real" testing, but I'll throw out a few thoughts.

Just like everything else in A/V, I always seem to need just a little more/better/quicker/faster/stronger/louder/etc. stuff to get the job done. I started with the Avia disc and a Radio Shack SPL and figured that was all I needed to setup everything I had. It probably was, but then I saw the graphs everybody else (it seemed) was posting, and I downloaded the free version of TrueRTA to see if I could do that, too. Since those results were a bit disappointing, I have since purchased the Level 4 True RTA, a Behringer ECM8000 Mic, Behringer UB802 MIxer, and I'm still waiting for a USB sound card for my laptop. Explaining all this to my wife sounded just like talking to my mom 40 years ago ("...but EVERYONE else has one").

Do I really need it? Probably not. The results from a basic SPL setup would probably be OK. But for me, the audio setup and tweeking is part of the fun of this hobby. Actually, I'm amazed at how inexpensive it is to put together enough parts to make a decent analyzer. The last spectrum analyzers I used were $25K - $30K HP's, so a couple hundred dollars seems like a bargain.

I know there are practical and accuracy reasons for using these tools. But for me - armed with the RTA, BFD, and Room EQ Wizard, I think it's going to be a lot more fun to go do battle with the acoustic issues in my new theater (if I ever get it built ), than with the SPL alone.

[Ht4me]

Well I do understand the tweaking...

I spent time to do both avia, & video essentials. I then laser aimed the sweet spots* to just behind the optimum seating. Timed the delays, set the distances, blah, blah, blah you know the usual stuff. WOW what a difference, but it was the 1st time set-up for the TX-DS 898
7.1 thx receiver too.( GIANT difference than a borrowed older Yamaha dts receiver).


* centerline of speaker aimed at the seated person(s) head, just behind the ears...
this set the toe-in to you... not just the LAR theory(looks about right)!!! I've done front of house sound live music concerts...etc. LAR theory always works(anyone other than crew working says its so...
try it you'll like it

OK OK let me know how you like the upgrade version on your laptop... & how it went please
whose will do the job best for the bucks...spent etc., leaning towards behringer 8024 & mic
or ? ? ? ?

Are we ever REALLY satisfied with how it looks, sounds, feels, real or perceived?

mike

[vierling]

If You have an RTA or spectral analizer, You begin to understand sound once You "see" how the freq´s work in the audible spectrum.
In a PC or Mac based Analysis Software You can get info, that You would never see in the SPL meter or low-price-resolution RTA´s.

Imagine that You are measuring the spl to calibrate your sub.
You have White or Pink Noise, but the speaker´s freq response is 10 dB higher in 80 Hz, the Spl meter will measure those extra 10 db´s, without noticing the peaking frequency.

There are great High-resolution analyzers based in a computer, which are cheap, easy to use and have a lot of extra tools that You can use.
* Real Time Analysis
* Noise Generator ( Pink & White noise, or choose any freq You want )
* Spectral analysis
* Equipment measurement ( amp´s, receiver´s, eq´s.. )
* Delay times
* levels ( SPL )
* Harmonic distortion calculation
* Room acoustics analysis

All You need is:

A measurement mic. I Use Bruel & Kjaer, but there´s a great option from Behringer ( ECM-8000 $65 ) that will give excellent results.

Microphone preamp with phantom power ( needed for the condenser mic´s ) Behringer ( MIC-800 $50 ) ,also check Tascam, M-audio, Creative...

PC or Mac with line in, or USB ( depends of Your preamp or external sound card )

Mic stand ( camera tripod & Gaff tape should work for a Home T )

Cabling ( XLR-Miniplug, Miniplug-RCA, XLR-XLR ) To interconnect the PC with the preamp, receiver and Measurement mic.

THE BASICS:
*Computer Line out goes into one of the receiver´s line in. ( Noise Generator )
*Measurement Mic goes into the mic´s preamp and receives Phantom Power from it.
*Preamp´s line out goes into the computer´s line in ( or USB )

The software shoots the generated signal ( Noise or freq ) into the receiver.
The Mic measures the noise that goes out from the speakers, and the software make´s the required analysis.

HOW TO GET STARTED:
http://www.siasoft.com/pdf/Started-with-SmaartLive.pdf


http://www.behringer.com/MIC800/index.cfm?lang=ENG

http://www.behringer.com/ECM8000/index.cfm?lang=ENG

SMAART LIVE (30 Day demo ):
http://www.siasoft.com/

SPECTRA RTA ( Demo ):
http://www.soundtechnology.com/RTA132.html

You may download the demo version ( Smaart Live has 30 days ! ) and start to do some experiments.
You can measure the signal that goes out from the computer ( If You Go to
the Recording controls in the sound card properties, Select "Wave out", or "Stereo out " ) and see how the freq response fluctuates when You play any sound signal in the computer ( Music files, or the noise generator that is included in the software )

If You wanna go Pro, read about the transfer function, phase, and spectrogram.

[brucek]

You may download the demo version ( Smaart Live has 30 days ! ) and start to do some experiments.

vierling, I invite you to take a look at the RTA that most people here at the shack use along with their BFD.

Room EQ Wizard or REW as it is known is free and arguably the best software available for this task.

See also this forums section called BFD | REW FORUM

brucek

[lcaillo]

One comment on the diagram above...I find that rather than using the sound card output, I use the output from my USB mic mixer (Tascam US122) which is quieter, more stable, and has flatter response than the sound output on my notebook computer. This might not be necessary for those with better quality sound cards, but with mine the differences were worth noting.

[vierling]

lcaillo wrote:

One comment on the diagram above...I find that rather than using the sound card output, I use the output from my USB mic mixer (Tascam US122) which is quieter, more stable, and has flatter response than the sound output on my notebook computer. This might not be necessary for those with better quality sound cards, but with mine the differences were worth noting.

In the transfer function ( Smaart Live.. ) You can even measure the sound card, and make the corrections, so You can have Flat response in the analyzer.

What do U use ? I can see that You like pro gear !

[lcaillo]

My problem was not the response but noise in my computer sound output. The Tascam is flat within 0.3 dB as I measure it with my scope with no compensation.

I am not really into pro gear, just wanted a good mic preamp and being a tech with some research background I prefer to eliminate variables than correct for them.

[vierling]

brucek wrote:

vierling, I invite you to take a look at the RTA that most people here at the shack use along with their BFD.

Room EQ Wizard or REW as it is known is free and arguably the best software available for this task.

See also this forums section called BFD | REW FORUM

brucek

Brucek,
I have downloaded the software, and have been playing with it the last hours.
I think it´s just great. But let me use a little more.
This is a great site, congratulations, I´ll be here asking, learning, and sharing.

Viva el Sonido.