# Behringer UCA202 low level signal input



## psilo (Mar 14, 2013)

Dear Sirs,

You are my last resort to solve it...

I bought last week UCA202 soundcard and Radio Shack meter. 

System: Win 7 32bit
Pc: Dell notebook
Soundcard calibrated succesfully
Radio shack calibration file loaded
Radio shack measurement indicated proper signal from my speaker = 75dB

I have following issue: the level of the input signal is too low(max -40dB). I have read several threads and tried everything. I have downoladed the Behringer drivers, installed them, uninstalled, no solution. Still the same, I can only lower the signal below those 40dB. 

I took the measurement and the message is that the input level is too low. Then comes the measurement that looks quite good. So everything is almost fine except such low level. I have checked severall times all the inputs. They are all set at max sensitivity. 

I will be glad if someone can help me, please. 

Best Regards

psilo


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## JohnM (Apr 11, 2006)

Please post your soundcard calibration measurement just to check it is correct, and one of your measurements with the RS meter (preferably the REW .mdat files).

What SPL range are you using on the RS meter? How have you connected it to the UCA202?


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## psilo (Mar 14, 2013)

Thanks for the input. I've done the experiment: another Acer notebook and it works. It seems that my Dell is having limited input gain somewhere. If you look at windows setting inputs is at max level (100). I will have to set up new system propably. 


Anyway using this opportunity I would like to kindly ask you for your opinion about my measurement:























The strange thing is that my Radio Shack was showing to 75dB and the measurement shows 115dB max. What I have done wrong? Did I set SPL meter incorrectly?

Best Regards

Pawel


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## JohnM (Apr 11, 2006)

Please attach the REW .mdat file of the measurement.


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## psilo (Mar 14, 2013)

Dear Sir,

I've done the measurement one more time, this time I was able to set SPL according to the Radio Shack. As enclosure I'm posting the measurements. I just wondering why the bass is starting from such high level from 3Hz to 30Hz? Is it any fault on Radio Shack? I'm quite sure that my set up is unable to deliver such level of low frequency. 

Set up: Focal Electra 1038 BE, Pass Labs XA60.5, Pass Labs XP-10, Linn Akurate DS,

Thanks in advance!


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## JohnM (Apr 11, 2006)

There is an odd artefact in the impulse response of that measurement, 12 ms ahead of the main peak. Try measuring with a single sweep rather than multiple sweeps, and see if a 256k sweep gives the same measurement results as the 1M sweep.

There have been one or two other examples of a steep rise in low frequency level, which I suspect is an interaction between the soundcard and the meter. Ignore everything below 30 Hz in that measurement.

And do call me John


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## sKiZo (Feb 9, 2013)

Excuse me, sir ... er ... John ...

So, you're saying the rise at the bottom is "normal" for a Behringer UCA202? That kinda sorta had me wondering ... here's my first soundcard calibration attempt ...










Looks pretty flat once you get into the usable freq range. Within a db, high to low. I expect I should be fudging the I/O levels to get more towards 0db on the scale?

And I haven't a clue what that "phase" line means. I'll be more than happy to ignore it if it's not necessary for eq'ing a room.


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## JohnM (Apr 11, 2006)

I wouldn't say the low end rise is 'normal', but it may be an effect of leakage current from the RS meter and the way the UCA202 input stage is configured. One thing which may help reduce the effect is to tick the "High Pass" box under Input Options on the REW soundcard preferences.

The loopback is badly wrong, there is some heavy EQ or tone control settings being applied. Make sure any audio enhancements are disabled.

You can ignore the phase trace.

To capture screen shots of graphs use the Capture button at the top left of the graph.


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## sKiZo (Feb 9, 2013)

dOH! and Double dOH!

Special note to self and anyone else who's interested. When calibrating the Behringer UCA202, turn MONITOR switch to OFF.



















Now THAT's more like it!

Played around with audio drivers and devices for a while on two different computers before I finally figured that one out. 

:dancebanana:​


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## psilo (Mar 14, 2013)

Hello John,

Here are new measurements.
View attachment p4.mdat


I have done different sweeps. I will be glad to hear your opinion about the room mod's etc. 


Take care

Pawel


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## JohnM (Apr 11, 2006)

Hi Pawel,

Single and 4 sweeps give the same results, with the strange glitch ahead of the main response in both, so doesn't seem to be an issue of multiple sweeps. Other than that measurements look to have worked fine. Did you have one speaker playing or both? It is better to measure each speaker individually.

There is a fairly strong resonance at about 32 Hz, but otherwise the response is quite well behaved. There are some sharp dips around 64 and 76 Hz, might want to see if moving the mic a foot or two forward or backward helps with those. Don't pay too much attention to the results above 5 kHz or so as the RS meter is not accurate at high frequencies.


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## psilo (Mar 14, 2013)

Hello John,

Thanks for your input. I was measuring only one speaker. Which meter can you reccomed for proper measurement of high frequencies? In fact my problem is the sound that is "too bright". I will play with the angle of the speakers (both horizontal and verical) to see how does it looks like. As for the listening only it seems that directing the speakers slightly to the listener works best (as for my ears). 

The Focal BE's are very demanding when it comes to positioning. They can reveal more and at the same time they can sound harsh.


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## JohnM (Apr 11, 2006)

For high frequency measurement it is best to use a measurement microphone, either USB such as the MiniDSP UMIK-1 or analog like ECM-8000 or EMM-6, but those will need a preamp with phantom power and are best calibrated, for example by Cross Spectrum in the USA or INF Acoustic in Europe. Another option would be a better SPL meter, like the Galaxy CM-140, but a measurement mic would be best.


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## sKiZo (Feb 9, 2013)

psilo said:


> In fact my problem is the sound that is "too bright". I will play with the angle of the speakers (both horizontal and verical) to see how does it looks like. As for the listening only it seems that directing the speakers slightly to the listener works best (as for my ears).
> 
> The Focal BE's are very demanding when it comes to positioning. They can reveal more and at the same time they can sound harsh.


Toeing the speakers is usually more of an imaging thing. In my own experience, you can tame the highs some, but end up losing definition in the soundstage. Same holds for changes in height. I'd say you'd be better served doing some room treatments. Lots of glass or reflective surfaces can cause all kinds of chaos on the top end but are easily treated with softer surfaces like drapes, blinds, bookcases, whatever ... anything that can help break up the reflections which are more than likely the real problem. 

You can pick up some 2/4 fiberglass ceiling tiles at the local lumber yard and just kinda move them about a bit glass side out to see what happens. Some of those new fangled peel and stick hooks to hang them, and once you get something that works, try to figure out how to make the changes permanent. I'd start with padding the walls directly ahead of and to the side of the speakers if they're within a foot or so as I'd expect that to be the biggest problem. I used full length fiberglass insulated drapes along the entire front wall and up the sides to a couple feet in front of the speakers on both sides to tame my room down, and it even looks good. I did eventually leave around three feet of bare wall at the corners directly behind the speakers as the full treatment was TOO much. I also added a panel above the listening position along the back wall to cut reflections there. I know that's kind of bass ackwards, as most recommendations are for padding the rear wall, but that's what works for me. Rule of thumb is to pad one of two opposing surfaces for the best results. 

Not saying toe and height aren't important ... just that they're more important as solutions to other problems. And don't expect what works for one setup will work for all - each room is unique. Tried and true methods do work, but how you incorporate and combine them is where the magic happens.

PS ... Took a peek in the manual and I see what you mean about the Focal line being a bit particular about placement. Mostly what I was looking for is whether they're isoplanar or line design. You want to avoid tilting the speakers if that's true. I went thru all that with my McIntosh XR16s and come to find out, the factory guys knew what they were talking about.

Of course ... goes without saying, you'll want to take care of all that before voicing the room as that could change significantly. Or not ... practice is good.


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## psilo (Mar 14, 2013)

Hi Skizo,

As enclosure you can find my room treatment. It's still quite poblematic what to do with the side walls, one one side there's window, on opposite... fireplace...

And there's wife...

If you look at the graphs that I have posted still there is TOPT from 0,55 - 0,60 and when playing loud it is simply too much of the high frequencies. My main concern is how to reduce it even more. As I wrote side wall are not really possible to dampen. Ceiling???


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## sKiZo (Feb 9, 2013)

I don't profess myself to be an expert, but ya ... the ceiling certainly looks like it could benefit from some softening. I don't expect the side walls are much of a problem as you've got blinds to break things up at the windows, and probably a chain screen on the fireplace? Besides ... that's gotta be what ... about a par three from one side of the room to the other ... <G>

More problematic might be the smooth square upper corner at the back. Whole lotta signal bounce going on there I imagine. Twere me, I'd consider maybe hanging some short heavy drapery between the rear speakers just behind the baffles. Assuming the rear speakers are mounted solidly to the wall, I bet you could make some brackets that would just go over the top of the speakers to support the rod. Some distance between the top of the curtain and the ceiling shouldn't be an issue as all you're trying to do is break up any reflection and bounce back there.

I'd also consider adding some texture to the ceiling itself, at least over the listening area. I was looking at this stuff a while back thinking it would be a great addition to the audio room ...

http://www.mywallart.com/designs

Plenty of random surfaces to kill any major reflections, and I'm thinking if applied right it could even trap a lot of the bad stuff. Add a couple of those faux wood beams that are the rage nowadays, and that'd even help isolate the untreated ceiling from the listening area.

Of course, just thinking out loud here ... hopefully food for thought. I'd go with the drapes first as that's something that would be easy enough to remove if it didn't work. 

Plan B ... if all else fails, you can tone down a bright speaker by adding a couple extra layers of cloth in front of the tweets and upper mids. Or if you're feeling ambitious, modify the crossovers, taking detailed notes to leave yourself a fallback position if it all goes horribly wrong. <G>

PS ... slow day today, so I was playing with Photoshop ...










Kinda dirty, but you get the general idea of continuing the theme you've got going on the walls. Maybe add some translucent panels to let the original light fixture work, or add some down spots around the perimeter. Me being crazy and all, I'd go with the downspots and add a lightshow ... <G>


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## vu2max (May 14, 2013)

Hello Home Theatre Shack! 

I seem to have reproduced the low input level the OP mentioned, when trying to check levels prior to making my first room measurement (I, too am using a Behringer UCA202 and a Dell, but I don't think these are the cause of the low level). I bought a Radio Shack Digital Sound Level Meter, RS 3300099, but when I use it to check levels at 75 dB (as shown on the RS 3300099 digital readout), no adjustments I can make in software can make the input sound level shown in the REW Soundcard Preferences panel increase above about -45 dBFS.

When I connect the RS 3300099 to an oscilloscope (1 MOhm input impedance) I find that the RS 3300099 output is about 10 mV RMS at 75 dB indicated, which apparently agrees with the -45 dBFS. (This is with A weighting set on the RS 3300099, C weighting is about the same). 

I will happily entertain suggestions that there's something wrong with my numbers; but if not, my question would be--

what would be the consequences for the measurements I soon hope to make of my room response, if I proceed with checking levels even though the RS 3300099 output level is apparently much lower than REW would like?

I'm pretty sure I expect the answer to be "few, if any", but I know I have the ability to make mistakes that would occur to few, if any people to make. Thanks in advance for any help!

Jim Reardon
Madison, WI


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## sKiZo (Feb 9, 2013)

... and you have verified that the monitor switch on the UCA202 is turned to "off"?


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## vu2max (May 14, 2013)

sKiZo--yes, monitor switch on UCA202 is off.


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## EarlK (Jan 1, 2010)

Hi vu2max ,

You should create & post a pic of your soundcard calibration ( like skiZo did in post #9 ) .

It should look just like the bottom pic .

Also take note, the OP bailed on using his Dell ( instead moving to his Acer ) effectively never discovering the problem with his REW/Dell setup .

One common cause ( for newbs, who are new to using the audio inputs of their computers OS ) can be that Win7 ships with the ability to make stereo recordings, *"turned off"* . It needs to be activated within the sound control panel .

See ; 










:sn:


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## sKiZo (Feb 9, 2013)

Your target is -6 to -18 ... you're nowhere near where you'd need to be to get reasonable results.

Don't know what to tell you other than posting up a pic of my soundcard setup screen. Compare it to yours and see if there's any difference. Mine already has the calibration file built and selected, but the switch settings are the same I used to get the cal file in the first place ...










Other than that, it's got to be the system volume is playing games with you. You'd need to check any specific sound software that's installed for your machine and also double check the windows volume control. Settings from one won't necessarily update the other. Step by step, and check progress as each step is completed. 

- Try tweaking your "sweep level" in the soundcard screen in REW. Default is -12, but you can go all the way up to -3. Bump it up a step at a time and check the results on the meter.

- Make sure the UCA202 (USB Audio Driver) is selected as the primary in the windows volume control, check "use primary only", and apply the settings. 

- Double check your mike mixer ... you may need to fiddle about with channel and master volume settings there to get a good signal into the Behringer. I use a Xenex 503 and the channel level is set to max with the main set to around 12:30 ...

- Update the soundcard drivers on your Dell to the latest available, and make sure any manual volume controls. Some laptops have a thumbwheel or slider for headphones that also affects master volume. 

- Worst case, set a restore position and try deleting all the soundcard specific software on your machine. You don't need it for the UCA202 -that's strictly a USB audio device and is plug 'n pray. That will definitely eliminate any potential conflicts between the Dell sound and the UCA202. You can always reinstall the Dell package at a later date. 

Luck wit it ... and be sure to post back with the results.

PS ... not sure if SPL meter calibration factors in here. You should do that anyway. Set your stereo volume to maybe 75db using your mike at the primary listening position and go thru the calibration procedure in REW. Always use the full range settings if you're eq'ing anything other than a sub.


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## JohnM (Apr 11, 2006)

vu2max said:


> When I connect the RS 3300099 to an oscilloscope (1 MOhm input impedance) I find that the RS 3300099 output is about 10 mV RMS at 75 dB indicated, which apparently agrees with the -45 dBFS. (This is with A weighting set on the RS 3300099, C weighting is about the same).


That's not a lot of signal, the analog RS meter puts out more than 300 mV rms at 75 dB SPL when on the 80 dB range. What range was your meter set to? You should use C weighting, by the way.


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## vu2max (May 14, 2013)

EarlK, sKiZo, and John,

Thanks for helping me with my problem. My soundcard calibration looks fine to me (see below), but if you see anything odd please let me know. My soundcard calibration went fine, and at some point my screen looked almost identical to the image sKiZo posted.

I followed up John's post--I see that the analog RS meter has a "range" setting, which the digital RS meter does not. Thus I think I won't be able to use the digital RS meter alone to check levels. 

Since I plan to use a dbx RTA-M microphone and a really nice preamp I have (called the Really Nice Preamp--made by FMR Audio) to make measurements, I think the following method will work for checking levels (please critique!): 

--set up the microphone end of the RS meter and the RTA-M microphone as close as possible, say 1 cm apart;

--connect the RTA-M microphone to the preamp, and connect the preamp output to the UCA202 input;

--set the REW output sound level to say - 9 dBFS, and adjust the volume on my speakers until the RS meter reads 75 dB;

--adjust the gain on the preamp until the input level in REW reads appropriately, say -15 dBFS;

--proceed with calibrating the SPL reading.

Thanks again for your help,

Jim

PS John, thanks for the reminder about using C weighting during level-checking.


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## JohnM (Apr 11, 2006)

All looks good - might want to try a loopback via the mic preamp, though looking at the info on that unit the result will probably look exactly the same as the soundcard loopback.


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## vu2max (May 14, 2013)

John,

Thanks for your continued attention. As per your suggestion, I did a soundcard-plus-pre-amp loopback calibration. I was curious about what to expect, since I've never used the pre-amp without turning on its phantom power (I wasn't sure that engaging the phantom power might not send a 48V DC bias into the Behringer UCA202's input, in which case I suppose it would never talk to me again). The result is shown below: it looks like the pre-amp causes the low-frequency roll-off to happen at slightly higher frequency than the soundcard alone, amounting to an attenuation of about 0.3 dB at 20 Hz, while the high-frequency end seems virtually unaffected. 

Onward!

With gratitude,
Jim


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