Rew Output signal not higher than 1V?

[jmol]

Hi forum member,

I'm having issues with REW measurements.
My setup:

-laptop
-steinberg ur22c
-dayton emm6 mic.

I want to perform a max spl test on my klipsch la scala drivers. However I'm having issues with the volt setting.

Now you should have 2.83V @ 1khz from 1mtr. Distance.
When I check the signal generator and put the testtone at 1khz and 0 dbfs, I'm getting only 1Volt output with the volume controle on my interface almost all the way up and the signal is staring to distort. What am I doing wrong?
The laptop line out volume is at maximum.

Hope someone Can help...?

 

[sam_adams]

The output spec to test with would be 2.83V into 8 ohms. To achieve that, you need to have an amplifier driving the speaker. A soundcard generally won't have the output current to drive a speaker to that level.

To know what the voltage output level from the sound card should be that would result in 2.83V out from the amplifier you would have to know the gain of the amplifier and set the sound card accordingly or you could measure the amplifier output with either a true RMS multimeter or an oscilloscope directly with an 8 ohm load (a 10 watt resistor would be adequate for brief setup adjustments) on the amplifier output terminals. Most soundcards will have an adequate output level to drive most amplifiers to 2.83V into an 8 ohm load without much difficulty.

 

[jmol]

I have a amplifier connected to the interface and a digital multimate with scope connected to the speakerwire output of the amplifier, that is the point where I measure

 

[sam_adams]

What is the make and model of your amplifier?

 

[jmol]

Kenwood L08M

 

[sam_adams]

That's an interesting design. Based on the input sensitivity spec of 1V RMS and the minimum rated continuous output power into 8 ohms, 170 watts, the gain of the amplifier is between 31dB and 32dB. That means that an input signal level of 0.070 to 0.080 volts RMS should give you 2.83 volts RMS at the output terminal with an 8 ohm load. Make sure that you don't have any DSP effects or odd internal signal routing/mix/gain settings in the UR22C setup.

 

[jmol]

Thanks for the help sofar, do you know any settings in particular that I Can look at or need to check?

 

[EarlK]

Your problem ( IMHO ) is this;

Steinberg UR22C

You'll need to learn how to get a clean signal routed through that dspMixFx ( mixer ) application before you can confidently do much within REW.

The reason?? That mixer application is intercepting ( controlling ) the signal before it's handed off to REW.

That mixer has countless ways to trip you up .

A soundcard with such a ( software based ) mixer is just not needed for REW work ( in fact, it does nothing but complicate the process for noobs ) .

You might want to consider exchanging that soundcard for the recommended 2 chnl type ; the Focusrite 2i2 .
- The 2i2 doesn't have ( need or include ) this sort of complicated software mixer > It only has a little window allowing the user to change the sample rate and buffer size .
- Here's a shot of it's ( very minimal ) interface ( hovering over REW's preferences window )



No fuss // no muss // to get in the way of doing REW measurement work.

 

[jmol]

I see now.... I have never seen that program/mixer on my laptop.

I will look at it to night, maybe I Can bypass the mixer somehow.
Keep you update, Just in case some else has the same problem

 

[EarlK]

The ASIO control panel ( + most likely the virtual-mixer for your soundcard ) is opened by choosing the yellow high-lighted button ( with REW's preferences window ).

 

[jmol]

Yes that asio panel (where I Can set the sample rate) is what I have seen, but not that dspmixfx.

 

[sam_adams]

You may also want to check if you have the current drivers, firmware, and software for the UR22C. Since Steinberg has their own Windows ASIO drivers for the device, there may possibly be a driver interference issue if you have ASIO4All or FlexASIO installed if you are using Windows. There are also separate USB drivers for macOS if you are using a Mac. This could possibly be an issue that another forum member who is using this device could weigh in on.

 

[jmol]

I Just checked the dspmixfx, there is nothing to change about the output voltage. The only thing that Can be changed is input voltage... And the program is secret running in de background as soon as you start REW.. Kinda werd, as there is also no bypass function.

 

[EarlK]

@jmol

I would recommend that you adopt a "Safety-First" protocol at this time.

Connect your sound card to an AVR first ( and have it send signal to your amplifier ). Set the AVR's level control to it's normal position for moderate listening volumes.
- It'll complicate your trouble shooting >> but that setup should save you some head-ache once you do discover the source of your low-signal problem.

Considering that you have not yet "Puzzled-Out" your signal problem, you don't want your lack of insight to cascade into something catastrophic for your speakers.

Having a tone generator ( REW ) directly connected to an amplifier ( if that amp is being run wide open ) is a recipe for blown components.

I sense that you might be only a single event ( button push ) away from delivering Full-Scale output voltage into a non-attenuated amplifier . That's a great way to blow up speaker components.

Now is the time to prevent that from happening.

 

[EarlK]

@jmol

I'd suggest that you bypass your Steinberg soundcard ( for now ) and instead run a 1K tone ( REW generated ) out to your PreAmp ( or AVR ) and then onto your Kenwood amplifier ( > speaker ).

You'll need to choose the Java drivers within REW ( in the "Preferences" window ) .

There's no reason that you shouldn't be able to get a ton of level into your speakers this way ( route ) .

Try this and report back please.