or Connect
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › TrueRTA-for-dummies
New Posts  All Forums:Forum Nav:

TrueRTA-for-dummies - Page 2

post #31 of 357
hi all,

just been playing with True RTA for a week or so, and this thread has been very helpful so far, so let me begin by thanking everyone for the great information.

i have a question, though. i am using an IBM ThankPad A30 laptop for the RTA, and was able to get the proper flattening second line on the RTA during the Sound System Calibration - however, if i run RTA with nothing plugged in to the sound card's ins or outs, i still get quite a bit of response on the SPL meter when i initiate the analyzer with "GO" button. there is also more "noise" present on the meter when using a mic than i would think is normal. is this indicative of power supply / hard disc noise? or perhaps of an inferior internal card?

i'm currently debating on whether to purchase an external sound card Soundblaster Live? or even maybe the M-Audio Duo USB or MobliePre USB (i am using the Behringer ECM800 mic).

i am using the RTA right now primarily to tune an automotive sound system with a 1/3 octave EQ - with mixed results so far.

thank you in advance for any thoughts, information, or advice, it is much appreciated.

-d
post #32 of 357
Just noticed this:

The digital version does not need any corrections when connceted from the output jack."

That's great if true (I have one), but why would that be so?

Isn't the digital aspect just a different way of displaying the level from the same microphone?

Thanks
post #33 of 357
Thread Starter 
Quote:
Originally Posted by noah katz View Post

Just noticed this:

The digital version does not need any corrections when connceted from the output jack."

That's great if true (I have one), but why would that be so?

Isn't the digital aspect just a different way of displaying the level from the same microphone?

Thanks

I don't know the reason, but I know atleast two occasions where a digital RS meter was compared to a Behringer ECM8000 mic and RS provided the exact FR without any CFs.
post #34 of 357
Thread Starter 
Quote:
Originally Posted by donovanhebard View Post

hi all,

just been playing with True RTA for a week or so, and this thread has been very helpful so far, so let me begin by thanking everyone for the great information.

i have a question, though. i am using an IBM ThankPad A30 laptop for the RTA, and was able to get the proper flattening second line on the RTA during the Sound System Calibration - however, if i run RTA with nothing plugged in to the sound card's ins or outs, i still get quite a bit of response on the SPL meter when i initiate the analyzer with "GO" button. there is also more "noise" present on the meter when using a mic than i would think is normal. is this indicative of power supply / hard disc noise? or perhaps of an inferior internal card?

i'm currently debating on whether to purchase an external sound card Soundblaster Live? or even maybe the M-Audio Duo USB or MobliePre USB (i am using the Behringer ECM800 mic).

i am using the RTA right now primarily to tune an automotive sound system with a 1/3 octave EQ - with mixed results so far.

thank you in advance for any thoughts, information, or advice, it is much appreciated.

-d

I would suggest you to buy a better, external sound card.

Have you checked your sound settings? Are you sure you are recording line-in? And have muted all except master and wave from the play side (including line-in)? Laptops usually have built-in mics which can mess things up. You should disable/mute them if you get an external sound card.
post #35 of 357
Quote:


I don't know the reason, but I know atleast two occasions where a digital RS meter was compared to a Behringer ECM8000 mic and RS provided the exact FR without any CFs.

I'd take that with a grain of salt. There have been a number of similar but different RS meters sold. The schematics of all the meters on Eric Wallin's mod page, two analog and one digital, all show the output jack tapping off after the A and C weighting filters. One easy way to tell would be to flip between the A and C settings on the meter with TrueRTA running. If the curve changes shape, the filters are being applied and you need a correction file.

Eric's page seems to be gone but here's the archive on the wayback machine.

http://web.archive.org/web/200411200...in/rsmeter.htm
post #36 of 357
Thanks, catapult.

Much to my shock, I read that I had sent Eric my very own RS meter!

So I guess I'm good to go
post #37 of 357
I'm planning to purchase the Level 4 version of TrueRTA... does it come with more mic calibration files?

I'm using an M-Audio Firewire 410 w/ any of the following mics (so how do I calibrate any of them?)

Shure PG81
Shure SM94
Shure KSM 109

AKG CK98
AKG CK93

I live in the Philippines and I don't know anyone here who can calibrate microphones... so does anyone have cal files for any of these mics? Thanks!
post #38 of 357
Those are all really nice general purpose recording mics, not test mics with flat FR. The Shure KSM 109 has reasonably flat response and goes lower than the rest.

Given your location it's going to cost you more money to get it calibrated, than it will to buy either the ECM-8000 or it's twin the Nady CM100.
post #39 of 357
Quote:
Originally Posted by catapult View Post

I'd take that with a grain of salt. There have been a number of similar but different RS meters sold. The schematics of all the meters on Eric Wallin's mod page, two analog and one digital, all show the output jack tapping off after the A and C weighting filters. One easy way to tell would be to flip between the A and C settings on the meter with TrueRTA running. If the curve changes shape, the filters are being applied and you need a correction file.

Eric's page seems to be gone but here's the archive on the wayback machine.

http://web.archive.org/web/200411200...in/rsmeter.htm



I bought my RS Digital meter late last year, and the A and C scale does indeed change the shape of the curve with True RTA running.

The filters are being applied to my meter's output jack!
post #40 of 357
Hi everyone, I am new here, what a great resource.
I just downloaded the trail version of Trueaudio RTA last night and I have a question. I conected a external sine wave generater (Rain Gain - 400hz @ 0dBu) into a channel on a Behringer UB802 mixer and ran the main out into the line-in on my internal sound card (Realtek AC97). I am trying to get familiar with the program and maybe I had something hooked up wrong. I wanted to measure the actual clipping point of the amplifier verses the indicaters on the mixer. The problem was the scope in RTA would show the signal clipping with the channel gain set almost to 0 and the faders at unity gain. Help?
post #41 of 357
I have downloaded the demo and when I start the software, I don't get any input response from the mic I am using. It is a condenser mic plugged into the M-Box which is plugged into the USB port. The input driver is RealTek AC97 Audio.

The Windows Sounds and Audio Devices properties only has one input driver and that is the RealTek driver.

Will this work? Or is there something else I need to do to get the software to recognize the audio input?

Thanks
post #42 of 357
Interesting guide, thank you! I've been playing with this a little but can't get decent results; my S/N ratio is ~25dB at best, maybe that's why. The reason I can't get better S/N is that I check input signal from the SPL meter with the 'scope functionality to check for clipping.

Is that a reasonable thought, that if measuring a sine wave it should sort'a look like sine wave even after passing through the speakers and the mic? And also that if measuring pink noise, the scope should show no full amplitude samples? Or will measuring work even if the SPL meter seems to be outputting a square wave?

Thanks in advance!
post #43 of 357
Hi All,

I am considering using TrueRTA in conjunction with a laptop. However, I don't plan on using a mic. I would just like to use the line in/out's to take some frequency response measurements of some amplifier circuits I'm designing.

I was considering the SoundBlaster Extigy or the M-Audio MobilePre USB. Does anyone have any comments on either?

I noticed that some external soundcards seem to have a headphone output, but not a 'line out'. Can they be used interchangeably?

Are there any special features I should look for (or stay away from)?

Thanks!
-Dan
post #44 of 357
OK, I've tried three different external USB sound cards and none will give me a flat line when conducting a Sound System Calibration.

I broke down today and bought the Sound Blaster Live! 24-bit USB external sounds card thinking this would resolve the issue. Unfortunately, it didn't. Everything is muted except for Wave out. What else could it be?
post #45 of 357
Quote:
Originally Posted by Nexus1 View Post

OK, I've tried three different external USB sound cards and none will give me a flat line when conducting a Sound System Calibration.

I broke down today and bought the Sound Blaster Live! 24-bit USB external sounds card thinking this would resolve the issue. Unfortunately, it didn't. Everything is muted except for Wave out. What else could it be?

I had the same problem, can't remember exactly how I fixed it but it was fixed with adjustments in the sound card's software driver.
post #46 of 357
Ken,

Thanks for the tip. I lowered the main volume and mic level to half and that did the trick.
post #47 of 357
Quote:
Originally Posted by Nexus1 View Post

Ken,

Thanks for the tip. I lowered the main volume and mic level to half and that did the trick.

Hope you didn't buy those three sound cards
post #48 of 357
I have completed purchase and installed Level 4 of RTA and, using a Behringer 8000 microphone along with a Soundblaster Live USB card on my pc, I began taking measurements of my room. The response graph that I end up with has various steep vertical spikes, for want of a better term, throughout the range. What am I likely to be doing wrong. Thanks in advance for your help. Phil Miller
post #49 of 357
Don't know if anyone was aware of it or not, but "duhouse" on Ebay it trying to sell "valuable information", a big chunk of which is simply a URL that points to this thread.

I'm mentioning and including it here because all he's trying to do is make a fast buck off of public information posted on this site as well as public domain information (he doesn't even have the brains/cajones to copyright the two page word doc he sends you) and it made me sick.

I would question the legality of his trying to SELL a link to a thread on this site as something he has the rights to and can make money off of. If it isn't illegal, it's certainly wrong. He takes the "I have 25 years of experience in the field and this is valuable information that the average consumer should know about." If the "average consumer" can't find the info via a simple web search engine, then they're far too stupid to manipulate the parametric EQ settings in a Denon receiver. Good grief.

To top it off, in addition to mentioning download TrueRTA (I can't disagree there, I own the 1/24th octave version myself), he also includes the following Denon "tweaks":


AVR-3806 Secret' Installer Modes



IR (Infrared remote) Disable Mode

*
1) IR Disable Mode Setup is available only from the Front Panel (not by remote)

2) Enter into System Setup, select 6. Option Menu', press ENTER'

3)* Scroll down to Exit' (of Option Menu), then press and hold (for 3sec.) the cursor left button' when the cursor points*to "Exit"*of #6 Option Menu.

4) Remote Lock setup mode will be activated. Select*on/off by cursor left and right button

-In Off' Mode FL Display shows as following *Remote Lock*On / Off* : < Off

* -In On' Mode FL Display shows as following**Remote Lock On / Off* : > On

5) Press ENTER' button to exit this mode.

6) When this mode is On', and an IR*command is received, AVR will show "Remote Lock On" on the FL Display

*This caution also appears for the power on sequence and in status*mode*
check on the FL Display

7) Even if IR Lock mode is on, AVR will continue to accept serial 232 commands



Front Panel LockOut Mode


Two Different Lockout Modes are available:

All Controls (Buttons and Knobs) on the Front Panel

a. Start with unit in Standby' Mode

b. From the Front Panel, press and hold,*STANDARD' and INPUT MODE' buttons and turn the Master AC power on

All Controls (Button and Knobs) on the Front Panel, EXCEPT Master Volume

c. Start with unit in Standby' Mode

d. From the Front Panel, press and hold, STANDARD' and EXT.IN' buttons and turn the Master AC power on
*
How to Defeat these modes:

From the Front Panel, press and hold* STANDARD' and ANALOG' buttons and turn the Master AC power on


When*each mode is On', and any button is pressed, AVR will show Panel Lock On' on the FL Display
*
*This caution also appears for the power on sequence and in status
mode*check on the FL Display

Even if Front Panel Lockout mode is on, AVR will continue to accept serial 232 protocol commands


**IR Disable and Panel Lockout Modes can be set*simultaneously or independently**




AVR-4306 Secret' Installer Modes


IR (Infrared remote) Disable Mode

*
1) IR Disable Mode Setup is available only from the Front Panel (not by remote)

2) Enter into system setup, select 6. Option Menu', press Enter'

3)* Scroll down to Exit' (of Option Menu), then press and hold (for 3sec.) the cursor left button' when the cursor points*to "Exit"*of #6 Option Menu.

4) Remote Lock setup mode will be activated. Select*on/off by cursor left and right button

-In Off' Mode FL Display shows as following *Remote Lock*On / Off* : < Off

* -In On' Mode FL Display shows as following**Remote Lock On / Off* : > On

5) Press Enter' button to exit this mode.

6) When this mode is On', and an IR*command is received, AVR will show "Remote Lock On" on the FL Display

*This caution also appears for the power on sequence and in status
mode*check on the FL Display

7) Even if IR Lock mode is on, AVR will continue to accept serial 232 commands




Front Panel LockOut Mode


Two Different Lockout Modes are available:

All Controls (Buttons and Knobs) on the Front Panel

e. From the Front Panel, press and hold,*DIRECT/STEREO' and INPUT MODE' buttons and turn the Master AC power on

All Controls on the Front Panel, except Master Volume

f. From the Front Panel, press and hold, DIRECT/STEREO' and EXT.IN' buttons and turn the Master AC power on
*
How to Defeat these modes

From the Front Panel, press and hold* DIRECT/STEREO' and Analog' buttons and turn the Master AC power on

When*each mode is On', and any button is pressed, AVR will show Panel Lock On' on the FL Display
*
*This caution also appears for the power on sequence and in status
mode*check on the FL Display

Even if Front Panel Lockout mode is on, AVR will continue to accept serial 232 commands


**IR Disable and Panel Lockout Modes can be set*simultaneously or independently**
post #50 of 357
OK, i downloaded and installed the demo of TrueRTA... i've a problem, simple i'm sure:

to quote:
"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."

OK, first of all... my soundcard input/output sampling frequencies can go up to 96khz, should i use that? or stick with the mentioned 48khz?
Second: where it says to use the same menu to start "sound system calibration" i do not have that in this menu. I've got "Line Input Calibration" and "line output calibration" only. Are these what is being referred to? When i click either of these, it is wanting me to get out a volt meter... which I so don't have. And hey, it doesn't include that in the list of 'what you need' in this guide for dummies either so uh... that's where i'm stuck, for now. Do i need a volt meter? *confused* or am i looking in the wrong place?

FYI: My soundcard is an SB Audigy, i'm connecting an RS Analog Meter (33-4050) with an Stereo 1/8 to RCA-Y cable to the same jack on the back of the Audigy as my headset mic (unplugged while messing with TrueRTA of course, no splitter there).
... I'm short on cables. Going to hit radio shack (source by circuit city here in canada) and buy some tomorrow, so i can actually get some measurements done.

Thanks a TON for any help you can provide, as i'm REALLY new at using this software, and audio 'tweaking' in general. ... Though i'm not a computer newbie, not at all, so that should help in the learning curve with this really thorough looking application!
post #51 of 357
Here's a screen shot of the menu as it should be and where the Sound System Calibration is listed. Hope it helps!
LL
post #52 of 357
One quick question, when doing the first part of the calibration, should the graph be in relative mode?

When I'm calibrating, if I don't have it set to relative mode, I don't get the flat line. If I have relative mode turned on, I get the flat line. In my case, at a 69.5 dB.

Is this correct?

Otherwise, it's really jaggid.

Also, should I be using a mono cable, or a stereo cable to link the two? Does it make a difference?

This is all on this card: http://www.auzentech.com/site/products/x-meridian.php

With Burr Brown opamps.

Thanks!
post #53 of 357
Quote:
Originally Posted by Red GTI VR6 View Post

One quick question, when doing the first part of the calibration, should the graph be in relative mode?

When I'm calibrating, if I don't have it set to relative mode, I don't get the flat line. If I have relative mode turned on, I get the flat line. In my case, at a 69.5 dB.

Is this correct?

Otherwise, it's really jaggid.

Also, should I be using a mono cable, or a stereo cable to link the two? Does it make a difference?

This is all on this card: http://www.auzentech.com/site/products/x-meridian.php

With Burr Brown opamps.

Thanks!

I'd be curious as to anyone's impressions or experiences with this card, in particular as it compares to the m-audio Revolution 7.1 and/or Audiophile 192 (both of which I have). I've got mixed feelings about both of my m-audio cards. When the 7.1 card is working, everything sounds fantastic, but then there are moments when it takes up so much cpu (I have a 2.4ghz p5) that during some heavy disk access times it can choke or stutter during playback of files. I also don't care for the 7.1's connectors (one coax digital I/O, which is great as optical stinks), but all the rest are mini jacks that you use mini to 2-rca cables for connections, and that really stinks. The audiophile 192 is a fantastic card, particularly for bringing in analog audio at the very highest quality (with XLR connections, monitor connections, etc., via a small extension multi-connector), but that's about it. I'd like to find one card that does both, I'm wondering if this is the card??
post #54 of 357
Quote:
Originally Posted by tlparker View Post

I'd be curious as to anyone's impressions or experiences with this card, in particular as it compares to the m-audio Revolution 7.1 and/or Audiophile 192 (both of which I have).

I cannot help you there, sorry. I've not listened to either of those cards. In fact, I haven't even listened to this card yet...lol I'm still in the process of making a bunch of modifications.

Quote:
mini jacks that you use mini to 2-rca cables for connections, and that really stinks.

I agree, I really wish these cards would come with RCA outputs. Because of that, I'm modifying my card: http://www.mp3car.com/vbulletin/showthread.php?p=979552

Quote:
I'd like to find one card that does both, I'm wondering if this is the card??

I cannot comment on the 7.1 features of this card as I'm not interested in using them. I'm using this card in my car for stereo play back. If for some reason, this set-up doesn't work, I'll be throwing this card in the home theater PC/system that we are starting to build and go with something like Mark Of The Unicorn UltraLite (http://www.motu.com/products/motuaudio/ultralite/)
post #55 of 357
Good stuff. . .I sense myself going out and buying a new mic, meter, and TrueRTA. . . damn you all
post #56 of 357
Hey guys, I've got the 1/3 octave version of True RTA (just thought I'd try it with more than just the 1 octave version before upgrading) and I'm using the Edirol UA-25 as a soundcard for my laptop.

I've connected the L RCA out to the L 1/4" in. Everything's set at 48KHz. The output pot is cranked and the input pot is at 12 o'clock on the edirol. I can't use the "sound system calibration" as it is greyed out on the menu so I can't click on it. I see it, it's there, just not active. How do I activate it?
post #57 of 357
How would you do your setup if you're using the software with laptop in a car? Where do you connect the line in and line out from the soundcard?
post #58 of 357
The sound system calibration is grey'd out on mine also. Do I need to upgrade to a higher level in order to activate it, or am I missing something?
post #59 of 357
OK, I answered my own question. Just upgraded to level 4 and every function is now available. Just goes to show you that you get what you pay for!
post #60 of 357
I'm not able to get a reasonable calibration on my Dell 300m laptopwith either my PCMCIA Audigy 2 ZS (even following the Audigy instructions mentioned in the TrueRTA FAQ) or with the integrated audio. What soundcards have people used successfully with their laptops?

Thanks,

Mike
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Audio theory, Setup and Chat
AVS › AVS Forum › Audio › Audio theory, Setup and Chat › TrueRTA-for-dummies