# My first measurements, please be kind :)



## Guest (Mar 9, 2007)

*My first measurements, Opinions please.*

Here are my REW measurements and to my untrained eye, they do not look that bad, opinions?

BUT, I took measurements with TrueRTA and they look MUCH different, which one is right? Could someone explain.

I, personally do not like the sound of my room, it is VERY live and my GIK acoustics will be arriving tommorow and will solve much of my problems.

Thanks,

Jim


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## Otto (May 18, 2006)

Yeah, that REW response is too good to be true! Maybe you have your loopback enabled in your soundcard software? I think it varies from soundcard to soundcard. See if you can find something about in your soundcard's software or in the control panel. 

Once you get that taken care of, your results will probably be more like those of TrueRTA.

Good luck!


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## Sonnie (Apr 11, 2006)

Yeah... I'm not sure what's up with REW there, but something isn't right. I'm sure some of our pros will chime in and lead you in the right direction. Looks like a pretty nasty peak at 40Hz, but that TrueRTA is an awful low measurement.


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## brucek (Apr 11, 2006)

> Here are my REW measurements and to my untrained eye, they do not look that bad, opinions?


You may have an internal soundcard loopback monitor turned on. Check that. Then be sure you have the soundcard calibration file and the microphone calibration file properly loaded.

When you connect a short from line-in to line-out (as you did to create the soundcard cal), do you get a flat line response (with meter cal file cleared) as you should?

brucek


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## Guest (Mar 9, 2007)

brucek said:


> You may have an internal soundcard loopback monitor turned on. Check that. Then be sure you have the soundcard calibration file and the microphone calibration file properly loaded.
> 
> When you connect a short from line-in to line-out (as you did to create the soundcard cal), do you get a flat line response (with meter cal file cleared) as you should?
> 
> brucek


This is a graph when I loopback the soundcard.


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## brucek (Apr 11, 2006)

Did you have the meter calibration file cleared and the soundcard calibration file loaded for the test?

brucek


edit: If the answer to that is yes, then you have an internal loopback monitor turned on in your soundcard software. If you connect a loopback cable and run a sweep, then the response that shows in the graph should be a flat line (response of the cable). The real response was actually the poor response of the soundcard, but then inversly compensated for by the soundcard cal file, which results in flat.

If an internal loopback is present, then all you see in the graph is the inverse of the soundcard file (which is what you show)...

brucek


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## Guest (Mar 10, 2007)

This was a clean install of REW, no meter calibration file (using ECM8000 mic, uncalibrated), soundcard was calibrated in TrueRTA (is this done in REW, if so how? I did not see it in the options).


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## brucek (Apr 11, 2006)

> I did not see it in the options


You require a microphone calibration file for the ECM8000 found HERE. Save target as ............

You require a soundcard calibration file. Information on creating one and using REW is found in the REW HELP FILES.
In the SETTINGS ICON routine there is an option to setup and use the soundcard calibration file.

These both must be in place before measuring with REW.

brucek


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## Guest (Mar 10, 2007)

brucek said:


> You require a microphone calibration file for the ECM8000 found HERE. Save target as ............
> 
> You require a soundcard calibration file. Information on creating one and using REW is found in the REW HELP FILES.
> In the SETTINGS ICON routine there is an option to setup and use the soundcard calibration file.
> ...


I did this and the results from a loopback cable to my Realtek, on-board soundcard is the posted graph. Does this look correct?


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## brucek (Apr 11, 2006)

When you use the loopback cable to check the results and effectiveness of your soundcard calibration file, you must (for this test only) clear the microphone/meter file, since the loopback cable obviously requires no calibration to be perfect.

So, if you have a proper soundcard cal file in place and forget to clear the microphone/meter calibration file and then perform the cable loopback test, you will get a graph that looks exactly like the inverse of the microphone/meter file. This is what I see in your graph (except you have substituted the C-Weight file instead - unclick it for this test). So, I would say you're good to go. To verify, do the loopback test with the mic/meter file cleared and the soundcard file in place.

Then you're ready to do measurements. Be sure to make your measurements with the mic/meter file loaded (and check the C-Weight box) so as to compensate for the meter.

When you post your graphs, the standard we use here is a 75dB target, with a horizontal scale of 15Hz to 200Hz and a vertical scale of 45dB to 105dB....

brucek

Note: The C-weight check box adds a C-Weight to the microphone readings _outside the limits of the mic/meter file_. So if the mic/meter file goes from 10Hz to 100Hz, then C-Weighting takes over (after that and before that) if the C-Weight box is checked. With no mic/meter file, then C-Weight takes over the entire range.


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## Guest (Mar 11, 2007)

OK, so I was not able to get an "official" preliminary reading on my room with REW, but you get the idea with the TrueRTA graph. I now have many GIK Acoustics panels installed (14), with 2 TRI-Traps coming in on Monday (for my screenwall corners) in this small room (10'w x 15'L x 7'H). Attached is my "current" graph, opinions?

Thanks,

Jim


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## brucek (Apr 11, 2006)

Fairly smooth response. It might be a bit heavy between ~35Hz and 80Hz. An equalizer would help there, bit I guess it depends on how it sounds?

brucek


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## Guest (Mar 11, 2007)

Thanks for the comments, It actually sounds pretty good, MUCH smoother then it was before, the BOOM is gone, much tighter and it hits lower. I will wait till my Tri-traps are installed before I take my BFD out of "bypass"mode and hook up my Midi interface.


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## brucek (Apr 11, 2006)

> MUCH smoother then it was before, the BOOM is gone


Yeah, you'll be surprised at how much the 15Hz to 25Hz range becomes more evident as you lower the ~35Hz and 80Hz even further. I suspect you'll need the BFD for that. You don't need to cut by much though. Everyone seems to agree that if you treat first and then EQ what's left, it's the best route to go...

Do you have the V1.4 firmware in your BFD or is it a FBQ2496 ?

brucek


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## Guest (Mar 11, 2007)

> Do you have the V1.4 firmware in your BFD or is it a FBQ2496


I have a DSP1124P but have no clue on verifying the firmware version. I've had it for about a year if that means anything. If is not the 1.4 version, is it updatable? How? Thanks.

Jim


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## brucek (Apr 11, 2006)

> I have a DSP1124P but have no clue on verifying the firmware version. I've had it for about a year if that means anything. If is not the 1.4 version, is it updatable? How? Thanks.


The midi interface doesn't work with units of version 1.3
You would need to purchase a V1.4 ROM and install it in the BFD if you want the midi to work.
To find out your version, power up the unit while holding down the Filter Select button and read the Version # displayed.
Read this thread.

Not a big deal. I've never loaded filters with a midi yet. I just put them in by hand. Takes a second. Read them right off the REW screen.

brucek


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## Guest (Mar 13, 2007)

Bruce, I am trying to use the Midi interface and it shows that it is sending the filter to the BFD but is there a way to verify this @ the BFD? Because the curve does not appear to change with the filters it is suggesting when I click on "find peaks" and create filters then send it to the BFD.

Thanks again,

Jim


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## brucek (Apr 11, 2006)

> I'd probably wire the VC's in parallel and bridge the amp to make sure both drivers are always seeing the same level of gain.


Sure, you can look at the filters loaded in the BFD program manually. Look at the BFD manual. It spells out how to load and monitor your filters.

Ensure the IN/OUT green LED is on solid. This engages the filters.

It's best to play around with the BFD a while before worrying about the midi stuff. That way you get used to how it operates.... 

brucek


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## Guest (Mar 18, 2007)

For the time being, I removed the BFD and did some experiments. The sub that I am using is a HSU VTK3 MK2 and did 2 graphs, one with one port open and the other with both open, here are the results. Opinions?


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## Vader (Jul 8, 2006)

<picks jaw up off the floor>

Jim, that's your response _before_ EQ'ing? Wanna trade houses? I would kill for that kind of response - especially since EQ'ing is not practical for me at the present time... I was gonna get a BFD and use REW to reprogram it, until I found out that a 75' USB or MIDI run was not feasible. So, until I get a laptop I'm kinda stuck (my response ain't _that_ bad, but yours surely puts it to shame...


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## Guest (Mar 19, 2007)

Thanks for the kind words and yes, this is before EQ'ing but AFTER putting in all my acoustic treatments from GIK Acoustics (Thanks Glenn!). SO my question is, should I EQ at all? I value the experts opinions here.

Thanks.


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## terry j (Jul 31, 2006)

should you eq? Sure, why not??? The cost of the BFD would surely be minor compared to the acoustic treatments, and the best of both worlds is achieved by BOTH room treatment and eq. The vast majority of the people on this forum would only get the benefits of a 'half-done' job, namely use eq without adequate room treatment.

You don't want to be on the other side of that coin??? ie room treatment and no eq?? Go that little bit extra that very few of us reach, PROPER room treatment and PROPER eq and then very quickly post us graphs of your result along with pictures of your room and be an inspiration to us all!!!

even tho I'm not an expert I hope you value my opinion ha ha.


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## brucek (Apr 11, 2006)

> SO my question is, should I EQ at all? I value the experts opinions here.


terry and I will disagree here. 

With a response like that why would you subject the signal to digitization, undigitization, noise, reduced dynamic range, phase issues, ground loops................................


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## terry j (Jul 31, 2006)

good point bruce. Is it really that bad?? If you had the DEQ would you consider it then?ie is there a point when you (bruce) would do it??


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## brucek (Apr 11, 2006)

> is there a point when you (bruce) would do it??


Both my systems have a BFD in them since the response of both is horrible without it. When I see some of these rather perfect responses without equalization, I usually recommend not using one.

I don't mind in the crummy second system, but I've considered replacing the 1124P in the main system with a FBQ2496 - higher input levels, better dynamic range etc.. just better specs...

brucek


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## Guest (Mar 20, 2007)

Thanks for the opinions. I do have a question, I do have a 1124P and if I leave it connected and in By-pass mode, does it do anything to the signal at all or is it totally bypassed?

And to anyone that desires a curve like this without EQing, hopefully you do not have a significant other that would not like the look of 14 bass traps in a small 10 x 15 room because the WAF is not too high with all this on the walls/corners. I personally do not care since I use this room to listen to music and watch movies (hence it is mostly dark when I use this room) It is my dedicated CAVE :T 

Thanks


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## Vader (Jul 8, 2006)

Jim,

While my wife is an incredibly understanding angel where my audio stuff is concerned, I'm sure she has her limits (and I don't want to push them)....


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## brucek (Apr 11, 2006)

> I do have a 1124P and if I leave it connected and in By-pass mode, does it do anything to the signal at all or is it totally bypassed?


No, it's not totally bypassed. The FBQ2496 is a hard bypass, but not the 1124P. The 1124P still runs through the ADC/DAC etc, etc. In bypass, all the filters are not engaged and the VU meters the input signal...

brucek


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## Guest (Mar 30, 2007)

I am still playing with sub placement and bass trap locations but I just got a new pair of speakers (monitors) and was wondering if a null is normal around the crossover point or do I have something wrong? I know that I am not showing the full response cureve, but I think that you get the point. Here is a graph and thanks.

Jim


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## brucek (Apr 11, 2006)

Adjust the phase control of the sub to smooth the crossover region.

If you don't have a continuously variable phase control and the 0 and 180 degree switch doesn't solve the problem, then the speaker distance control of the sub can act as a good substitute.

Great response by the way...............

brucek


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## Guest (Mar 31, 2007)

Thanks, will have to use the distance option since my HSU sub has only 0/180 degrees


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## Guest (Apr 1, 2007)

Thanks for the advice Bruce, here is a graph of all my (your  ) work. I really appreciated your help, still not sure if I should EQ the sub, but for now it is not.

Jim


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## brucek (Apr 11, 2006)

> still not sure if I should EQ the sub, but for now it is not.


Your response is really good. You simply do not need any EQ....

brucek


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