Measurements For Everyone

[fuzz092888]

Yeah.

Why can't the Audyssey RC measure my speakers like this and plot the response graph? Or do they ?

Oh it does (sort of), but you have to have audyssey pro or know how to get into the software to see any of additional information.

 

[AcuDefTechGuy]

Oh it does (sort of), but you have to have audyssey pro or know how to get into the software to see any of additional information.

Damn. No free lunch.

I thought I saw the very crude plots (displayed on TV screen) after I ran Audyssey. Looked like 3 response graphs: Audyssey off, Audyssey on, Audyssey flat. I could be wrong.

 

[cpp]

Damn. No free lunch.

I thought I saw the very crude plots (displayed on TV screen) after I ran Audyssey. Looked like 3 response graphs: Audyssey off, Audyssey on, Audyssey flat. I could be wrong.

never ever saw a graph out of my 4311. Maybe I'm in the dark on that one.

 

[AcuDefTechGuy]

never ever saw a graph out of my 4311. Maybe I'm in the dark on that one.

Maybe it's only available on my AVP-A1 and AVR-5308.

Think I'll play with Audyssey tomorrow on my day off.

 

[fuzz092888]

From John, author of REW about calibrating the stock soundcard on a laptop and how that relates to a USB mic.

The average laptop soundcard is very good nowadays. If you are using a USB mic there is no point in doing the soundcard calibration, just double check that tapping the mic doesn't result in any sound from the speakers.

 

[Grador]

Ugh, been there done that. If you forget to turn off mic monitoring you are in for quite a "fun" ride.

 

[fuzz092888]

Ugh, been there done that. If you forget to turn off mic monitoring you are in for quite a "fun" ride.

Tell me about it. I cringe just thinking about it.

 

[mtrycrafts]

REW and MiniDSP teamed up awhile back so that nearly everyone could have access to a reasonably price DSP unit with active measurement and correction capabilities. Now the two have done it agin, except in the area of measurement and acoustical analysis. The free software from Home Theater Shack, REW can now be combined with a new measurement microphone from MiniDSP. This microphone is accurate from 5Hz-20KHz +- 1db with a unique correction file for each microphone. While this isn't anything new or especially revolutionary, what comes next is. This is one of the few truly plug and play microphones out there. No drivers. No software. Compatible with Mac, Windows, and Linux. Absolutely fantastic so far. How about an external sound card or 48V power supply? Nope. USB powered (5V) microphone, compatible with all major operating systems and it comes with it's own correction file to give you +-1db from 5Hz-20Khz. Certainly nothing extraordinary when matched up against all that there is to be had out there, but definitely looking like a real winner. So how does it stack up against the competition?

UMIK-1
5Hz-20KHz +-1db
USB powered
Unique calibration file included with sensitivity calibration for SPL readings with REW

Dayton EMM-6
18Hz-20Khz
Phantom power required
Unique calibration file easily downloaded
$38

Behringer ECM8000
15Hz-20Khz
Phantom Power Required
No calibration file
$55

Now both the Dayton and the Behringer are also available from cross spectrum labs where they create a unique calibration file for each microphone, albeit for an additonal fee. They can either calibrate a microphone you already own, or you can purchase a calibrated mic from them. If you choose to go that route, the Dayton measures and Behringer will then be provided with calibration files from 5Hz-25Khz, although no word on the +- of those frequency responses. You can also get calibration files for 45 degrees and 90 degrees in addition to the 0 degree standard calibration file with an upgrade. The Dayton mic from Cross Spectrum Labs is $75 + shipping or $90 + shipping for the upgrades. The Behringer is $90 + shipping or $105 + shipping for the additional cal files.

So to answer the question you've been dying to know the answer to.....the UMIK-1 is $75 + shipping which is typically $20 for a total of $95. Not exactly the breath taking deal you thought? Well consider your alternatives. With either of the other two microphones you're still left without a power supply or external sound card which could add $100+ dollars to your total costs. If you bought a preassembled hardware+software kit like the Dayton offering or maybe the XTZ measurement kit you're looking at over $300.

Given the current competition I think the UMIK-1 has really carved a spot out for itself with both seasoned measurement experts and, maybe even more importantly, those who wish to get into measurements for the first time. With the simplicity of the unit, combined with fact that you don't need anything else to actually use it except REW, which is free, makes it extremely appealing for first timers. The extremely flat frequency response, plug and play simplicity, and competitive pricing make it one of the best deals around currently.

Hopefully when I receive mine I can give additional impressions and observations.

Sounds interesting. I might have to break down and get them both.
A question: where does the test tones come from, internally from REW or a CD/DVD/BD? I have test Cds but have to wire the .1 ch so it is driven by the front inputs.
If in REW, is it 1/3 octave of full band?

 

[Grador]

Sounds interesting. I might have to break down and get them both.
A question: where does the test tones come from, internally from REW or a CD/DVD/BD? I have test Cds but have to wire the .1 ch so it is driven by the front inputs.
If in REW, is it 1/3 octave of full band?

Internally from REW, and you can set it for whatever you want. You set the range of the sine sweep, and can then apply smoothing to the graph as desired.

 

[PENG]

Yeah.

Why can't the Audyssey RC measure my speakers like this and plot the response graph? Or do they ?

I've run Audyssey several times in the past and I recall the response graphs, but I never thought much about it.

I think the Audyssey OFF looked very similar to the ON & FLAT graphs.

I only have XT and I guess my HT room is a bit like yours in a sense, the flat graphs does not alter the freq response much at all, may be 1, or 2 dB at the most, but it only shows the freq response graph. I do know it does a lot more with the sub though and that's the main reason I have it on all the time except for serious Stereo listening when I use pure direct with any subs.

 

[PENG]

never ever saw a graph out of my 4311. Maybe I'm in the dark on that one.

Even the XT version shows some bar graphs, your XT32 for sure will save a few graphs to give you some visual, most likely in the parameter check screen.

 

[mtrycrafts]

Internally from REW, and you can set it for whatever you want. You set the range of the sine sweep, and can then apply smoothing to the graph as desired.

Thanks. Then, if I understand this, you need to feed the audio out from a laptop into the receiver, right?
Now I wonder if that audio is multi channel and perhaps can be fed through HDMI? Would be nice to be able to direct to the .1 ch as well as all the others.

 

[monkish54]

So the mic completely bypasses one's sound card?

 

[fuzz092888]

Thanks. Then, if I understand this, you need to feed the audio out from a laptop into the receiver, right?
Now I wonder if that audio is multi channel and perhaps can be fed through HDMI? Would be nice to be able to direct to the .1 ch as well as all the others.

Correct.

REW does mono or stereo, not multichannel. You would have to have RCA L/R and split to do more than two speakers at one time, however the way it was explained to me was to do each speaker individually and then average them together. Not sure if that's the right way or not.

 

[Grador]

however the way it was explained to me was to do each speaker individually and then average them together. Not sure if that's the right way or not.

Personally I would do each individually AND simultaneously then average all three. Taking each speaker individually does not show you the way they interact in your room which can be very important.

Monkish: correct, the microphone has it's own ADC and does not use your sound card at all

mtrycrafts: To do a measurement of the sub alone you would have to remove the speakers from the equation in some way. This can be achieved by disconnecting them, or best yet feeding full range signal to your sub by pre-outs.

REW really shines for more practical measurements of your systems ability but can be a little cumbersome for more specific uses.

 

[mtrycrafts]

Correct.

REW does mono or stereo, not multichannel. You would have to have RCA L/R and split to do more than two speakers at one time, however the way it was explained to me was to do each speaker individually and then average them together. Not sure if that's the right way or not.

Personally I would do each individually AND simultaneously then average all three. Taking each speaker individually does not show you the way they interact in your room which can be very important.

Monkish: correct, the microphone has it's own ADC and does not use your sound card at all

mtrycrafts: To do a measurement of the sub alone you would have to remove the speakers from the equation in some way. This can be achieved by disconnecting them, or best yet feeding full range signal to your sub by pre-outs.

REW really shines for more practical measurements of your systems ability but can be a little cumbersome for more specific uses.

OK. I wasn't going to do all the speakers at once but each individually as I have in the past with just the RS spl meter and test tones, a bit of pain in the back. The two subs I will need to do together at the same time though to EQ as one. I tried to do it individually but when they were together split and mono mode the FR changed, of course. Worked nicely with both and EQ as one.

Now, another question came up after reading the link auto-eq with rew. It mentions a need for a plug in. Is that so, or that is with a different setup?

 

[BoredSysAdmin]

Hmm good point. I'm not entirely sure either, I'm just going off what I've found and asked on the HTS REW forum. The REW developers or mods of whatever they are who answer told me that the stock macbook pro soundcard should fine, and that for windows based laptops it just depends on what soundcard it already has in it and that the easiest way to know for sure if the soundcard will be good enough would be to either google it or come back on the forum and ask. That's probably a question that is going to become more relevant with the UMIK and Dayton coming out (the whole USB mic, but using the stock input for calibrating thing). Would be interesting to hear what they have to say about that.

Ok, just to clarify my point - USB 1.0 which have been used in many usb dacs is limited to lower resolution of data sampling due to deficiency of bandwidth.
USB 2.0 based solution normally allow higher precision of sampling - I think 24/96 is the norm.

I'm not 100% sure this added resolution is significant for audio measuring, but if it is than it's possible going with phantom mic and usb 2.0 dac might provide better result

Again, these are speculations, not facts.

Just want to clear something else:
Due to microphone is usb based - so the measuring portion will have no dependency on PC/MAC hardware sound card, other than to feel an audio signal to the system tested.

 

[BoredSysAdmin]

So the mic completely bypasses one's sound card?

Yes, USB mike bypasses one's sound card - see my comment above

 

[Grador]

OK. I wasn't going to do all the speakers at once but each individually as I have in the past with just the RS spl meter and test tones, a bit of pain in the back. The two subs I will need to do together at the same time though to EQ as one. I tried to do it individually but when they were together split and mono mode the FR changed, of course. Worked nicely with both and EQ as one.

Now, another question came up after reading the link auto-eq with rew. It mentions a need for a plug in. Is that so, or that is with a different setup?

miniDSP calls their software "plug ins" for reasons I do not understand at all. If you want to do ANYTHING with a miniDSP you need a "plug in".

 

[hjustin]

So I'm still buying an Omnimic kit.