Level is Low 54.2 db REW - HELP

**Guiria** · **08-02-08, 12:39 AM**

I've followed the steps of soundcard calibration, level check, and SPL meter calibration without any apparent issues. I've calibrated the sound to 75 db

When I go to do a measurement and I click "Measure>Check Levels" I get the response "Level is Low 54.2 db" I've gone through the whole setup process again and I'm missing something because I get the same notice. I can even adjust the volume during the check level test up or down and I still get the exact same response.

I'm using the Audio Advantage SRM with Windows XP and the digital RS meter.

Any help would be appreciated?

Thanks in advance.

**thewire** · **08-02-08, 02:41 AM**

What do the error messages in the REW soundcard debug file say?

**Bori** · **08-02-08, 03:36 AM**

I have the same issue. I am using my onboard Sound card.

**JohnM** · **08-02-08, 06:49 AM**

What do you have the frequency range of your sweep set to, and what are you measuring? If your sweep end is set to 20kHz (say) and you are measuring a sub then when REW checks the levels across the range of your measurement it will get no response above a few hundred Hz and the result will be a low level. Make sure the sweep end frequency is 200Hz if you are measuring a sub.

**Guiria** · **08-02-08, 10:28 AM**

I used "use subwoofer to calibrate REW" and I am testing from 20 Hz to 200 Hz. I'm testing in 2 Ch. stereo mode on my AV with no signal processing enabled. My mains are on during testing. Should they be turned off? My initial goal is measuring in room response and since my xover is 80 hz the mains play a big roll when measuring up to 200 hz.

I know my sub doesn't play anything at 20 Hz (lowest in room response using pink noise is 26 Hz). Should I move my lower limit up to 30 or even 40 Hz?

I won't be able to get back to testing for a few days so hopefully I'll have a lot of approaches to tackle the problem by then.

I will have to check the debug file and see if that calls anything out.

**brucek** · **08-02-08, 11:01 AM**

Quote:

I used "use subwoofer to calibrate REW" and I am testing from 20 Hz to 200 Hz.

Sounds like you've done everything correctly. I would set the measurement sweep from 0Hz-200Hz.

Keep in mind that the Check Levels routine in the Measurement screen and the Check Levels routine in the Settings screen use different values to generate the pink noise level setup test signal.

The Check Levels routine in the the Settings screen uses the fact that you have the Check/Set levels with Subwoofer pull-down selected to generate its test noise (this a band limited signal with a low and high cut of 30Hz - 80Hz).

REW double checks and verifys that the end frequency of the sweep that you have selected in the Measurement panel roughly matches the test signal setting (for sanity). Its Check Level routine uses the end frequency as the test pink noise hi-limit cutoff. So if you had 200Hz as the end frequency to measure for your sweep, you can see how the pink noise would be different (between the two Check Levels) and as such the low level signal you're experiencing. This can be considered normal.

Long story short, use the correct test signal (subwoofer or mains) to set up the Settings screen Check Levels routine levels. If you've done this correctly and the Measurements screen Check Levels sanity test passes, don't worry about a level warning.......

The usual progression of measurements starts with sub alone without the mains, since we are usually equalizing the sub, we want to get it by itself first and equalize it before adding the mains. Once the mains are added we can usually adjust the subs phase to smooth out the crossover area and all is fine.
When you add the mains, don't change anything about the testing from 0-200Hz - only reset the Check Levels...

brucek

**Bori** · **08-04-08, 10:10 PM**

Quote:

JohnM wrote:

What do you have the frequency range of your sweep set to, and what are you measuring? If your sweep end is set to 20kHz (say) and you are measuring a sub then when REW checks the levels across the range of your measurement it will get no response above a few hundred Hz and the result will be a low level. Make sure the sweep end frequency is 200Hz if you are measuring a sub.

How the you change the sweep end frequency?

**brucek** · **08-04-08, 11:06 PM**

Quote:

How the you change the sweep end frequency?

Press the Measure button and click the thumbwheel that says End Freq...........

brucek

**Bori** · **08-07-08, 05:15 PM**

I still get low level on my test, but this is the way my graph looks. Let me know what you think. By the way I am using Soundblaster live 24bit.

**brucek** · **08-07-08, 06:54 PM**

Quote:

Let me know what you think.

Change your axis to the standard we use here.

Vertical = 45dB-105dB and Horizontal = 15Hz-200Hz.....

brucek

**Bori** · **08-08-08, 05:45 AM**

Quote:

brucek wrote:

Change your axis to the standard we use here.

Vertical = 45dB-105dB and Horizontal = 15Hz-200Hz.....

brucek

How does it look now?

**brucek** · **08-08-08, 06:54 AM**

It certainly takes a dive above 60Hz. I wonder what crossover setting you are using?

The low end humps up quite a bit. This could be due to corner positioning. Try moving it out of a corner (if that's where it's located).

Moving the sub around may also help the peak you are experiencing at 50Hz.

brucek

**Bori** · **08-08-08, 11:15 AM**

I have Dual 3.3 turbos with a MBM-12. I have the dual 3.3 set to 50hz and the MBM-12 set to handle everything above that. The crossover on the receiver is set to 120hz. Yes iI have one 3.3 in each front corner of the room. The MBM-12 is located nearfield. What about the error I get that the level is too low? Should I worry about this?

**brucek** · **08-08-08, 12:05 PM**

Quote:

What about the error I get that the level is too low? Should I worry about this?

You have to keep in mind that the Check Levels routine in the Measurement screen and the Check Levels routine in the Settings screen use different values to generate the subwoofer pink noise test signal.

The Check Levels routine in the the Settings screen uses the fact that you have the Check/Set levels with Subwoofer pull-down selected to generate its test noise (this a band limited signal with a low and high cut of 30Hz - 80Hz).

REW double checks and verifys that the end frequency of the sweep that you have selected in the Measurement panel roughly matches the test signal setting (for sanity). Its Check Level routine uses the end frequency as the test pink noise hi-limit cutoff. So if you had 200Hz as the end frequency to measure for your sweep, you can see how the pink noise would be different (between the two Check Levels) and as such the low level signal you're experiencing.

Long story short, use the correct test signal (subwoofer) to set up the Check Levels. If you've done this correctly and the Measurements screen Check Levels sanity test offers a level warning, you can usually ignore it, as long as you don't have some incorrect end frequency such as 20KHz...

I don't have a lot of advice for anyone trying to set up a sub and a mid-sub other than good luck. It's an interesting idea in theory, but I have my reservations about it in practice.

brucek

**Bori** · **08-08-08, 02:56 PM**

So I can proceed with moving the subs around and playing with the crossover so I can try to get the flattest response.

**brucek** · **08-08-08, 03:13 PM**

Quote:

playing with the crossover

Yeah, you will have to do some playing around with positioning to pull off a smooth response when dealing with a mid sub. Your REW measurements look fine though....

Personally, I guess I would start by getting the best response with the low sub(s) first. Then add the mid sub and try and integrate it as best as possible. Then add the mains and try and integrate them to the mid.....

brucek

**Bori** · **08-08-08, 03:31 PM**

Do I turn off Audessy when I do this?

**brucek** · **08-08-08, 03:44 PM**

We've had members who have had success either way. I guess if you are going to add Audyssey into this, I would leave it off and go through the routine as I mentioned above and then run Audyssey and see what it does for you. If it's horrible, I don't have a lot of suggestions other than to leave it turned off.

brucek

**zilbenz** · **08-12-08, 03:25 PM**

I too get the same message during Check Level that the level is too low (around 33) after following all instruction and set everything to 75.

But I also found the instructions in Set Up which says to increase AV volume or sweep level to increase it to an louder level.

And so I increase the AV volume and increase Sweep Level say to 9 or 10 to get a louder level for Measure run.

Is this considered wrong? Thanks.

Chris

**brucek** · **08-12-08, 03:54 PM**

Quote:

And so I increase the AV volume and increase Sweep Level say to 9 or 10 to get a louder level for Measure run.

Is this considered wrong? Thanks

No, it's fine. Personally, I would set up the Settings screen Check Levels routine using a -12dB sweep output level and then with a 75dB reading at the listening position obtain a correct -12dB input level, and then run the Calibrate SPL routineand set to 75dB, and subsequenctly ignore any warning I get in the Check Levels of the Measurement screen as long as my end frequency was at 200Hz.

brucek

**zilbenz** · **08-12-08, 06:17 PM**

Quote:

brucek wrote:

No, it's fine. Personally, I would set up the Settings screen Check Levels routine using a -12dB sweep output level and then with a 75dB reading at the listening position obtain a correct -12dB input level, and then run the Calibrate SPL routineand set to 75dB

Yes, those are all the steps I followed as outlined in your REW instructions.

Quote:

and subsequenctly ignore any warning I get in the Check Levels of the Measurement screen as long as my end frequency was at 200Hz.

Thank you for saying that because that was what I did on many occasions. Really appreciate your clearing that up.

Chris

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