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post #1 of 358 Old 08-22-2005, 02:19 PM - Thread Starter
 
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Since HTSpot transferred this quide into section where you have to be a paid member to get in, I decided to copy it here. Hope you'll all enjoy!

TrueRTA is a nice and small RTA-program (Real Time Analyzer) made by John Murphy. The free demo of the program can be downloaded from here. Unfortunately the demo is quite limited so you can't really use it efficiently. To make the most of it, you need to purchase an upgrade. True Audio offers four different upgrade levels from 1 to 4. I definitely recommend level 4, because this way you get the full 1/24 octave resolution, which is almost a MUST, especially if you are planning to some EQ'ing with BFD or similar. Level 4 retails $99.95, but it's all worth it. If you absolutely can't make it, take level 3, it comes with 1/6 octave resolution. Here is a little proof why 1/24 is recommended.

Before anything, read the help files/topics, they are very helpful.

The program itself is very small (~1.4MB installed), but the project files are around 10MB each, so make sure you have atleast that much of free space on that drive.

1. What do we need?

-Computer/laptop equipped with a decent soundcard.
-Microphone (and preamp if needed).
-Some RCA cables between them.

Minimum System Requirements:
A 500 MHz Pentium III class PC with 64MB RAM running
Windows 98/ME/NT/ 2000/XP

Most modern soundcards will work just fine, for example almost any Soundblaster (Live, Audigy, Aydigy2 etc.) is fine. Soundcard must have line in and line-out connections. If you have some expensive soundcard, it will most probably work. Integrated soundcards like nVIDIA Soundstorm will work, but they are more difficult to calibrate, you need to set the input/output levels very carefully with them. I haven't yet seen a laptop with a decent soundcard. Most of them won't work. Use a USB or PCMCIA soundcards with laptops. For example M-Audio MobilePre USB is great. They retail around $100 - $150.

You can use the Radio Shack SPL meter as a microphone, but its accurancy is not very good. You can find few compensation charts for it, but none of them is perfect for your meter. They are just estimates. You can download the correction file from here. NOTE: Check the end of this post, more info about RS. Save it as a text file along your other correction files (in "TrueRTA/Mic calibration files" folder). Frequency response of the RS meter limits up to around 10kHz (even with correction file). With the correction file it is reasonably accurate down to 15-16Hz. I personally have the older analog model, but the newer analog will work just fine. The digital version does not need any corrections when connceted from the output jack.

Much better choice is a Behringer ECM8000 microphone and a Behringer UB802 preamp/phamtom power. It's basically very flat even without any corrections, but here is a correction file for it too. Don't use the file that comes with TrueRTA. This better file is actually property of Edward Mullen (perfect for his mic), so everyone who's using this file, remember to thank Ed!

2. Calibration

First you have to make a simple loop from line out to line-in using the normal RCA cables and proper 1/8" connectors. You can just connect the other channel (use left) or both. Before you start the program, check your soundcard settings. Enter by double-clicking the speaker icon on the lower right corner of your desktop (if you can't see this, enter through control panel). In playback side all sliders except wave/mp3 and master volume should be muted. If you can't see the line-in slider, enable it through options/properties and mute it. This is crucial if you don't want to have some nasty microphone feedback. In recording side select line-in, if you can mute the others, do it. With most soundcards you can set all slider at full. If you have the nVIDIA Soundstream, set line-in slider at about 1/4. Now you can start the program itself.

By default the program is monitoring only the left channel, normally you don't have to change this. Now enter the "Audio I/O" menu and check that both sampling frequencies are set to 48 kHz. If your soundcard doesn't support these, use something lower for example 41 kHz. Now using the same menu, start "Sound System Calibration". Follow the instructions and you should see two lines on your screen. First a line something like this.

After a second or two the line should straighten up.

If the first line is not completely straight, lower the sliders like we learned before. If there is no line at all, check the connections. If you can't have a straight line, your soundcard is propably very cheap and will not work.

Now you can load the mic calibration file. Enter the same menu and "Open a mic calibration file". Select the correct file and open it. The range will throw you out, but use the buttons on the right side to make it readable (use around 0 dB - 120 db range). Now you should see a line like this.

The absolute level (SPL's) might not be the same as in my picture. If you can't see the SPL readings, push down the SPL button. Notice that if you want to do the sound system calibration again, you have to unload the mic calibration file before doing it.

3. Connections

Unhook the loop at first.

If you have the RS meter: RS meter has an analog output using a single female RCA connector. Connect this into the line-in of your soundcard. Use proper adapter if needed. Connect both left and right channels from line out into your stereo system (usually pre/pro/amp). Use AUX/CD or similar analog inputs. Set your RS meter to C-weighting (very important, though some sources claim that output is not weighted, I will research this matter) and fast (actually fast or slow doesn't matter). Use the 80dB range. Make sure you have a fresh battery. Place the meter on a tripod or similar and point it towards the speakers. Place the tripod at the listening point (sweet spot, ear level).

If you have the ECM8000 or similar: You need an XLR cable (male/female) between the mic and the mixer. Mixer also supports 1/4" jack. Mixer output is either normal RCA or 1/4" jack. Check that microphone control knobs are near center, phantom ON, Main Mix around center. Output can be either Main Out, Ctrl Room Out or Tape Out.

4. Settings

When you have all the nessecary connections ready, we can look at some of the settings.

This is the start screen of the TrueRTA. You can use either pink noise or quick sweep (QS) for measuring. If you have a proper mic, both ways will give very similar results. With RS meter the QS can be a little bit inaccurate at the lower end of the spectrum. The pink noise is more reliable, but also much slower.

Normally you should have the "L IN", "MIC CAL" and "SPL" buttons pushed down. "RTA Resolution" as high as you have purchased. "Speed Tradeoff" 20Hz. Averages 1. "Input/output sampling frequency" should be set to 48 kHz, if your soundcard supports them. Use lower if not. "CPU speed setting" anywhere you like.

5. Measuring

Select the "Pink N" from the left (Wave). Push the green "GO" button and you should see a wavering line like this.

That is some backround noise of your room and also the noise from the whole measuring line. The lower the better. Now set averages 100 and the line should settle down. Averaging means that the program takes every 100th, or what ever number you have set, sample into account. John Murphy suggest a value over 1000, but I think it's too much. If you are using QS, averaging doesn't affect at all. Now you can push the Generator ON. Adjust the volume from your pre/pro/receiver so that the meter reads around 75 dB - 80 dB. It sounds quite loud, but it's not dangerous. Keep the noise running around 5-10 s so that the line settles down. Now you should see a line something like this.


You can adjust the range if you want a closer look. This one is also smoothed, you can find the smooth option from the utilities menu.


6. Advanced features

TrueRTA has an option to calibrate the absolute SPL level. Play for example 100Hz or higher sine wave (but below 500 Hz) and check the reading on your meter. You can play the tone using the built-in generator or you can use a cd/dvd. Have the program measuring all the time (GO button down) and enter Audio I/O / SPL Calibration menu and enter the SPL reading. Now the program is calibrated and it's showing absolute SPL's (=real). Notice that if you are playing a pink noise or similar wide band signal, you can see the real SPL level by pushing the dB button down. The line itself is at much lower level (~50 dB), but this is just because the nature of the signal. If you are measuring pure sine waves, the absolute level can be seen straight from the line itself.

Quick Sweep is a much quicker way, but I've noticed that sometimes the RS meter gives false readings especially at the lower end, since the sweep is so damn quick. You can make the sweep "slower" (actually it just sweeps narrower range) by lowering the input sampling frequency. I suggest 22.05kHz. If you set it too low (8kHz), your computer will slow down significantly. Pink noise is the "safe way".

You can also use Avia/DVE or similar disc for measuring. Find a suitable sweep (do not use single sine waves) and remember to have "PEAK HOLD" pushed down. Start the analyzator (GO) and start the sweep. Stop the analyzator (STOP) after the sweep and you should have the line on your screen.

Another cool feature is the Oscilloscope mode. You can easily check for example if your calibration signal is clipping or not. It's quite easy to use. Just have the signal running using the built-in generator and push the GO button (remember that you have to have the loop again). Adjust the range if you can't properly see the shape of the signal. Now you can set your levels very accurately. Just add the level (input/output sliders and Ampl. level) until the signal clips. Then back off by few dB until the signal doesn't clip anymore.

Here you can see a perfect waveform of a 1kHz signal.



Here you can see the same signal, but now it's clipping heavily.



7. Quick recap

-Make a loop
-Run sound system calibration (adjust levels)
-Load the mic calibration file
-Connect the cables, line out -> receiver and mic -> line-in
-Calibrate absolute SPL if needed
-Measure your FR using either pink noise or QS

Copyright Ilkka Rissanen
-------------------------------------------------------------------

I must have forgotten something or maybe you didn't understand something. Please, post questions and I will make a small Q&A list out of them.

-------------------------------------------------------------------
Radio Shack SPL meter info:

Today I got my professionally calibrated microphone. Even without any correction files, it's only 0.5 dB off at 10 Hz. Pretty impressive. It was calibrated against B&K 4133 microphone.

I have now measured it against my analog RS meter. As I have said, the RCA output jack is weighted (C or A). But as Ethan showed, it appears that the output of the RCA jack of the digital RS meter is unweighted when set to C-weighting, when set to A, it's A-weighted. When set to C, it has a flat FR atleast down to 20 Hz.

Here is a TrueRTA screen of my results.



As you can see, even with those general CFs, the RS meter is still below the true FR. It tracks the mic down to 40 Hz, but below that it's off. You need to compensate even more than for example 7.5 dB @ 20 Hz. Around 11.5 dB seems to be more closer. Of course every RS is different, so this might not apply to your RS. Although me and my friends have measured total of three RS meters (analog) and they all give pretty similar FR.

http://personal.inet.fi/private/ilkka/RS_calibrated.txt

Here is a calibration file which turns my RS into calibrated measurement microphone. When using this file its FR is within 1 dB (10 Hz - 200 Hz) from my calibrated microphone. It may not be as perfect with your RS, but much better than the general CFs. Notice that general CFs are way off below 15 Hz.

Analog version:
Use atleast general CFs or this file when measuring with the TrueRTA or smilar. Same thing if you are measuring manually (looking at the needle). You can use the rough corrections below, if you don't want to check the file (if you are measuring manually, add those corrections, do not subtract them).

Frequency / Correction
10 Hz +5 dB
12 Hz +6 dB
16 Hz +14.8 dB
20 Hz +11.5 dB
25 Hz +7.8 dB
30 Hz +5 dB
40 Hz +3.2 dB
50 Hz +2 dB
80 Hz +1 dB
100 Hz +1.2 dB

Digital:
Do not use any correction files when measuring with TrueRTA or similar. The output of the RCA jack is unweighted when set to C-weighting. When measuring manually, add corrections shown above to the readings.
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post #2 of 358 Old 08-22-2005, 02:43 PM - Thread Starter
 
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Pictures of the connections (text/pictures property of Floyd Pierce) Thanks Floyd!

Note that I'm using a laptop so the Mic symbol would equate to line in with a normal sound card and the headphone symbol would equate to line out.

The loop connection for sound system calibration: (loop is just a stereo mini straight through)

[IMG]http://www.***************.com/html/spotadmin/uploads/loop.jpg[/IMG]

Radio Shack SPL Meter as Microphone:

[IMG]http://www.***************.com/html/spotadmin/uploads/RS_SPL_as_mic.jpg[/IMG]

Both hookups:

[IMG]http://www.***************.com/html/spotadmin/uploads/hookups.jpg[/IMG]

The more elaborate setup with a Behringer Mic and Mixing Console (provides phantom power to the Mic):

[IMG]http://www.***************.com/html/spotadmin/uploads/w-mic_and_pre-amp.jpg[/IMG]

The 2 following pics are a Closer look at Mixing Console connections:

[IMG]http://www.***************.com/html/spotadmin/uploads/mic_preamp.jpg[/IMG]

[IMG]http://www.***************.com/html/spotadmin/uploads/ub802.jpg[/IMG]
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post #3 of 358 Old 08-23-2005, 12:21 PM
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Excellent primer. Thanks for the work. Perhaps I'll add a bit on using ETF in a similar manner when I get the chance.
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post #4 of 358 Old 08-24-2005, 10:24 AM
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Thanks for the post, that is very helpful...
I think I am going to get the same software as you..
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post #5 of 358 Old 08-28-2005, 11:47 AM
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On rec's from Forum members I've purchased TrueRTA and and an M-Audio FastTrack USB for the mic interface

http://www.m-audio.com/products/en_u...kUSB-main.html )

I'm still a bit unclear about how to set up the initial calibration loop for TrueRTA ...

I'll be using an outboard M-Audio FastTrack for the mic preamp and USB functionality.

FastTrack has mic input (XLR) and 1/4" input (for guitar or other line in.)

FastTrack has USB output and RCA stereo left and right outputs.

Laptop has USB port, mic input (tiny jack) and headphone output (tiny jack).

Two questions:

(1) in normal use (once all is calibrated) the proper setup is (a) mic into XLR input of FastTrack and (b) FastTrack into laptop via the USB port and (c) laptop headphone out into receiver's line in (for sending the pink noise, etc, signal to the speakers.)????

(2) in calibration loop/setup (a) headphone out from laptop into line in for the FastTrack and (b) USB from the FastTrack into the laptop via the USB port?????

Thanks!!!
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post #6 of 358 Old 08-29-2005, 06:57 AM - Thread Starter
 
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Quote:
Originally Posted by Brucemck2 View Post

On rec's from Forum members I've purchased TrueRTA and and an M-Audio FastTrack USB for the mic interface

http://www.m-audio.com/products/en_u...kUSB-main.html )

I'm still a bit unclear about how to set up the initial calibration loop for TrueRTA ...

I'll be using an outboard M-Audio FastTrack for the mic preamp and USB functionality.

FastTrack has mic input (XLR) and 1/4" input (for guitar or other line in.)

FastTrack has USB output and RCA stereo left and right outputs.

Laptop has USB port, mic input (tiny jack) and headphone output (tiny jack).

Two questions:

(1) in normal use (once all is calibrated) the proper setup is (a) mic into XLR input of FastTrack and (b) FastTrack into laptop via the USB port and (c) laptop headphone out into receiver's line in (for sending the pink noise, etc, signal to the speakers.)????

(2) in calibration loop/setup (a) headphone out from laptop into line in for the FastTrack and (b) USB from the FastTrack into the laptop via the USB port?????

Thanks!!!

Which microphone do you have?

To your questions: You have to forget the internal soundcard of the laptop.

(1) In normal use (once all is calibrated) the proper setup is (a) mic into XLR input or into line-in (1/4") of FastTrack and (b) FastTrack into laptop via the USB port and (c) Fastrack headphone out or Fastrack stereo RCA output into receiver's line-in (for sending the pink noise, etc, signal to the speakers.).

(2) In calibration loop/setup (a) from headphone out or stereo RCA output of Fastrack into XLR input or line-in (1/4") for the FastTrack and (b) USB from the FastTrack into the laptop via the USB port.
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post #7 of 358 Old 08-29-2005, 08:44 AM
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Hi,

I just purchased the TRUE RTA, and I have download it to my lap top. I need to get a mic now. I have the Radio shack analog SPL meter, but I want to get a better one. If I decided to get the Behringer Mic do I need to get the Mixing Console?
Can I just use the Mic only and plug it direct to the laptop?
may be I will get an adapter that will convert the XLR to RCA.
Or can I get a simpler mixer?

The mixing amp looks complicated, I don't even know what's all the button for.
is there a smaller version without all the buttons.
I want everything to be simple

thanks

Mario
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post #8 of 358 Old 08-29-2005, 09:13 AM
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You need a mic pre-amp with phantom power for the Behringer ECM8000. Your options include the mixing console shown above (there are a few different models) or a simple mic pre-amp like the Art MicroMix, Rolls (I forget the model number), etc. A basic mic pre-amp will run you about $50 and the mixing panel would run a bit more, but not much.
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post #9 of 358 Old 08-29-2005, 09:16 AM
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BTW: It also requires a soundcard that has a real stereo line-in which many notebooks lack.
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post #10 of 358 Old 08-29-2005, 10:34 AM
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Can't he just use the RS meter's output jack and published calibration curves?

Noah
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post #11 of 358 Old 08-29-2005, 11:55 AM
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Yes, but since he asked about getting another one I gave him the important points. The RS meter could be used with the published calibration info and it would be reasonably accurate.
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Ikka ... Thanks!!! Your user guide was very helpful.

To answer your mic question: I'm using a five year old calibrated mic that came with my GoldLine 1/12th (low) 1/3rd (elsewhere) RTA

Had to replace the M-Audio FastTrack with a MobilePre. Salesman that pitched the FastTrack said they were "identical, except FastTrack was single channel rather than two channel". He was right, IF you ignore the phantom power differences!
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post #13 of 358 Old 08-29-2005, 02:30 PM - Thread Starter
 
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Quote:
Originally Posted by Brucemck2 View Post

Ikka ... Thanks!!! Your user guide was very helpful.

To answer your mic question: I'm using a five year old calibrated mic that came with my GoldLine 1/12th (low) 1/3rd (elsewhere) RTA

Had to replace the M-Audio FastTrack with a MobilePre. Salesman that pitched the FastTrack said they were "identical, except FastTrack was single channel rather than two channel". He was right, IF you ignore the phantom power differences!

Yep, Fast Track doesn't have a phantom power, so you can't use it for example with the ECM8000 (w/o an external power).

I think your mic is pretty good. Although calibration should be done every year, but it is still much better than say the RS meter.
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post #14 of 358 Old 08-29-2005, 02:33 PM - Thread Starter
 
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Quote:
Originally Posted by sholei View Post

Hi,

I just purchased the TRUE RTA, and I have download it to my lap top. I need to get a mic now. I have the Radio shack analog SPL meter, but I want to get a better one. If I decided to get the Behringer Mic do I need to get the Mixing Console?
Can I just use the Mic only and plug it direct to the laptop?
may be I will get an adapter that will convert the XLR to RCA.
Or can I get a simpler mixer?

The mixing amp looks complicated, I don't even know what's all the button for.
is there a smaller version without all the buttons.
I want everything to be simple

thanks

Mario

If you have a laptop, then I would recommend getting a M-Audio MobilePre USB soundcard (external). It has also phantom power for the ECM8000 mic. Very easy to use and not too many buttons, unlike the UB802 shown above.
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post #15 of 358 Old 08-30-2005, 05:07 PM
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Ilkka:

Thanks for the primer! When will you follow up with ETF for Dummies?

MT
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post #16 of 358 Old 08-31-2005, 02:39 PM - Thread Starter
 
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Quote:
Originally Posted by MikeTz View Post

Ilkka:

Thanks for the primer! When will you follow up with ETF for Dummies?

MT

Didn't BradJudy promised to do that one?
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post #17 of 358 Old 08-31-2005, 03:11 PM
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Quote:
Originally Posted by Ilkka View Post

Didn't BradJudy promised to do that one?

I'll work on it once I have my mic back. I now have to different setups (one with a MobilePre and one with a separate mic pre-amp) so I can show two different connection setups. If I'm really feeling motivated, maybe I'll also work on one for the new R+D.
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post #18 of 358 Old 09-01-2005, 09:37 PM
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Nice thread! I didn't know you could connect the RS meter straight to a laptop!

Quote:


I haven't yet seen a laptop with a decent soundcard. Most of them won't work. Use a USB or PCMCIA soundcards with laptops. For example M-Audio MobilePre USB is great. They retail around $100 - $150.

In the pics, you seem to be using your laptop, didn't you say that laptop soundcards are horrific and don't work very well?

Quote:


I just purchased the TRUE RTA, and I have download it to my lap top. I need to get a mic now. I have the Radio shack analog SPL meter, but I want to get a better one. If I decided to get the Behringer Mic do I need to get the Mixing Console?

Quote:


Yes, but since he asked about getting another one I gave him the important points. The RS meter could be used with the published calibration info and it would be reasonably accurate.

Quote:


BTW: It also requires a soundcard that has a real stereo line-in which many notebooks lack.

why would you need a stereo input if you're using one mic?

Ok, so I'm a bit confused now.. Laptop + RS meter, does this actually work? Or it depends on the stereo line in? (how can you know if it is?) And if it actually works, it works? No need for an external soundcard? (good quality?)
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post #19 of 358 Old 09-04-2005, 08:27 AM
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For the RS meter, doe it made a difference to use the digital or analog meter for the RTA software?
Will the reading be more accurate, if using the digital meter?

thanks
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post #20 of 358 Old 09-04-2005, 10:17 AM - Thread Starter
 
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Quote:
Originally Posted by sholei View Post

For the RS meter, doe it made a difference to use the digital or analog meter for the RTA software?
Will the reading be more accurate, if using the digital meter?

thanks

Check the end of my post. Some new info.
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post #21 of 358 Old 09-04-2005, 10:29 AM - Thread Starter
 
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Quote:
Originally Posted by Grandarf View Post

Nice thread! I didn't know you could connect the RS meter straight to a laptop!

In the pics, you seem to be using your laptop, didn't you say that laptop soundcards are horrific and don't work very well?

As I said, those are not my pics or my laptop. I just linked them.

I don't suggest using built-in soundcards (laptop or home PC). Usually they are crap. Use external soundcard, that is my adwise.

Quote:


why would you need a stereo input if you're using one mic?

They are always stereo inputs.
Quote:


Ok, so I'm a bit confused now.. Laptop + RS meter, does this actually work? Or it depends on the stereo line in? (how can you know if it is?) And if it actually works, it works? No need for an external soundcard? (good quality?)

It may work or it might not work. If it has a real line-in and line out connections, you have a chance. Make a loop and run a sound system calibration. If the first line is almost flat and the second (after calibration) is totally flat, it's working.

http://audio.rightmark.org/download.shtml

This is a good program (RMAA 5.5) which shows if your soundcard has a flat FR. It shows also THD, IMD, etc.
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post #22 of 358 Old 09-07-2005, 10:00 PM
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I get a large, narrow peak at 60hz using the rat shack meter to a soundblaster Live. Is this a ground loop? I never get ground loops from HTPC or dvd player on this system so I dunno why it's there. Not to mention the outlet there is only 2 prong (no ground, old house).


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post #23 of 358 Old 09-08-2005, 08:18 AM
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Where was this months ago when I had to wing it to figure out how to use RTA
The pics are especially helpful.

Seth


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< -- While that looks simple enough, click it for answers to many a question.
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post #24 of 358 Old 09-12-2005, 10:33 AM
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The sound card on my Dell 700m didn't work so I picked up a Soundblaster Live USB and it worked fine.

I'm thinking about buying an ECM8000, I think the RS 4db correction discrepancy at 20hz is way too much and above 1k it looks almost useless. I have an older RS meter (probably more than 10 years old), it could even be further off. Has anyone used the Rolls MP13 microphone preamp? I wonder how it compares the the UB802.

Thanks
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post #25 of 358 Old 09-12-2005, 10:36 AM
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Ilkka, What are the two sets of correction numbers starting at 515.625hz on you correction table?
thanks
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post #26 of 358 Old 09-12-2005, 11:50 AM
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Ken,

I haven't tried the Rolls, but I do have an ART MicroMix which is a single-channel mic pre-amp with phantom power and runs ~$50 from Sweetwater music. It works well. It isn't as flexible as a UB802, but it's very simple to use.
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post #27 of 358 Old 09-13-2005, 10:34 AM - Thread Starter
 
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Quote:
Originally Posted by Kenrosencpa View Post

Ilkka, What are the two sets of correction numbers starting at 515.625hz on you correction table?
thanks

That second set is phase correction numbers for the RS. Numbers up from there are from the file which is available on the ETF site.

That ETF file doesn't have any corrections below that frequency, which is bad if your meters output is C-weighted or more (like mine). Digital version and some older analog versions output a flat signal, so for those the ETF file is pretty good.

Otherwise use my file.
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post #28 of 358 Old 09-23-2005, 03:00 PM
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Does TrueRTA apply "C weighting" to the displayed data?

Reason for asking is that Room EQ Wizzard asks whether to correct for measurement devices's C weighting (when transferring data from TrueRTA to RoomEQwizzard.)

Thanks!
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post #29 of 358 Old 09-24-2005, 05:13 PM - Thread Starter
 
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Quote:
Originally Posted by Brucemck2 View Post

Does TrueRTA apply "C weighting" to the displayed data?

Of course it doesn't.

Quote:


Reason for asking is that Room EQ Wizzard asks whether to correct for measurement devices's C weighting (when transferring data from TrueRTA to RoomEQwizzard.)

Thanks!

I wouldn't use this option unless you have a good C-weighted SPL meter. Radio Shack doesn't follow C-weighting. I would use the same correction file as in TrueRTA also in Room EQ Wizard.

But if you are transferring TrueRTA files, you don't need to apply any corrections, since TrueRTA has already corrected them once (don't do double).
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post #30 of 358 Old 09-25-2005, 07:45 PM
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Hey guys, i didn't get to try my lappy sound output to see if it worked, but there's a little gadget which might fix that problem:



I'm having a hard time finding it in Canada so I might have to order it directly from the site... Anyhow, I'll use it with optical to the Behringer DEQ Digital EQ, so the sound quality from the laptop will finally be top notch. (also ordered ECM-8000 mic) The USB 'sound adaptor' is only 30$, I think it should be superior to the laptop integrated soundcards...

Anyhow, I'll give an update if I find one, but it looks like it could be a very good solution if your laptop has a bad sound output. I know mine isn't very good, lot of interference from hardisk, its integrated DVDRom, etc.. its very noisy, I guess even with the analog from USB you wouldn't get any of that interference...



[edit] I just got it. Its really not very good with analog (noisy, moreso than my integrated laptop AC97!), and I can't get the digital output to work with my DEQ 2496
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