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Room EQ Wizard (free measurement and parametric EQ setup software) - Page 3

post #61 of 855
John, I saw the exact same kind of thing when I went back a couple of days ago and measured my sub's response with ETF after using the RoomEQ Wizard. After checking LF response with ETF, I popped up the waterfall plot and was astounded at the reduction in resonances. I quite honestly thought I was setting something in ETF incorrectly, but now I know I wasn't. Thanks for all the hard work you've put into this. It's an amazing tool!

Gear mentioned in this thread:

post #62 of 855
Hello John,

The program has come a long way and is looking very fine indeed.

As a comparison, in the graph where you show the resonance reductions, could you please tell us the frequencies, Q, and amplitudes for the filters you applied?

Many thanks,
George
post #63 of 855
Thread Starter 
Hi George,

Here you go:


Regards,
post #64 of 855
Thank you!

I was curious as to how you were manipulating the gains of the filters. I see that you have chosen to cut all peaks with no boosts. I assume by doing so that you must increase the overall gain of the signal to get back to "reference," 75dB seems to be the usual target.

The other alternative would be to boost some of the valleys and end up using less overall gain.

Is one method preferred over the other? I imagine it could be a bit of juggling act, too many and too deep EQ cuts and the overall volume might have to be set too high causing amplifier clipping, too many or too much EQ boosts and the EQ might clip.

Thanks again,
George
post #65 of 855
Thread Starter 
Because the low frequency modes were so strong the peak level after correction was 15dB lower than before, but the shift in the sub cal level was much less because the resonances contribute only part of the overall level, albeit a big part in bad cases.

The worst dips after correction were only 5 or 6dB and quite narrow, just a few Hz. I don't find it useful to try and fill anything beyond a broad dip, if the bandwidth of the dip is less than about 1/6th of an octave I'd leave it alone.

You have to cut the peaks if you want to get rid of the overhang in the time domain, if you were to boost the other parts of the signal instead (the areas between the resonances) you just end up with extended decay times everywhere, which would sound awful.
post #66 of 855
John - this is an excellent little program and just what I have been looking for for the last few years since I got my BFD. I have been able to significantly improve on the manual method of setting the filters - Thanks!

I've got 2 ideas for enhancements which would be really great to see in new versions:
- add a way to upload multiple seating position recordings and have the tool calculate a best set of filters for say the three primary seats instead of one only (using some sort of interpolation method) - this would help to minimize the one biggest issue of using EQ to resolve resonance issues. Room modes that are excited by front to back wave interference would be best suited for this enhancement as the peaks and valleys would be at more or less at the same frequency for seats in the same row. Though now thinking about it, I suppose I could combine the three input curves via a rms formula before uploading - hmmmmm - gonna try that tonight!
- add the ability to calculate filters that are in the LFE channel yet above the cross over frequency (i.e. input xover freq and slope, and have a "stronger" filter if peak is greater than xover). This would allow for more accurate setting of filters which occur in 80-120 hz range which you would normally not be able to control very well using a BFD and a cross over of 80Hz. I have had some success in doing this by hand but would be really cool to see the tool do it automatically.

At any rate - great tool and thanks!

Dave
post #67 of 855
Thread Starter 
Quote:


Originally posted by DaveBoswell

- add the ability to calculate filters that are in the LFE channel yet above the cross over frequency (i.e. input xover freq and slope, and have a "stronger" filter if peak is greater than xover). This would allow for more accurate setting of filters which occur in 80-120 hz range which you would normally not be able to control very well using a BFD and a cross over of 80Hz. I have had some success in doing this by hand but would be really cool to see the tool do it automatically.
Dave

This is already catered for by the existing Target curve, which incorporate bass management at the specified cutoff (in 10Hz steps from 30Hz-150Hz). The target follows the bass management/LEF cutoff curve so corrections against the target are correspondingly higher for peaks that are above where the bass management roll off starts. If you want more than this do the measuring correcting directly from your PC to the sub via the BFD (so no LFE cutoff from your processor), but still use the target curve for your processor's LFE cutoff rather than a flat target, then you would get the effect you are after - or am I misunderstanding?

Glad you like the app, BTW
post #68 of 855
OK, back to a basic setup question ...

I would like to use this on a laptop that has only the single pin jacks for microphone and speakers. Is this doable? Would I need to get splitter cables to separate the left/right signals to RCA plugs for each single jack? If so, do I then use an aditional RCA to RCA plug to close the loop?

I have a Radio Shack SPL meter, but I'm confused here on the mechanics of the cabling I'll need with this laptop.

Could someone clarify the step by step cabling I'd need for this laptopp? Or maybe even an actual picture would be worth a thousand words.

Much thanks in advance,

Tim
post #69 of 855
Though it pertains to different software (EFT), there is a visual depiction of the necessary connections about halfway down on this page. Just substitute your receiver for where they have the BFD, and instead of using the RCA>1/4" connector depicted, you'll need an RCA Y-cable like one of these.

BUT: As per Room EQ's setup instructions, I don't believe a Mic In input will be sufficient. You need a Line In.
post #70 of 855
Hi,
my laptop doesn't provide the line in. Any recommendation for a usb soundcard providing this which includes midi interface?

thanks Starc
post #71 of 855
Quote:
Originally Posted by Starc View Post

Hi,
my laptop doesn't provide the line in. Any recommendation for a usb soundcard providing this which includes midi interface?

thanks Starc

Don't know about a USB soundcard with MIDI port, but I'm using the SoundBlaster MP3+ (USB), and a separate USB-to-MIDI cable. Works fine!
post #72 of 855
First I would like to thank you for making this program and sharing it with us.
What I would like to ask if you would consider adding support for the ULTRACURVE PRO DEQ2496 to do auto calibrating? On the page I linked to it has the "MIDI Implementation Chart" if that is what is needed to do so.

Thanks in advance.


peace
post #73 of 855
Thread Starter 
Quote:
Originally Posted by SIMJEDI View Post

What I would like to ask if you would consider adding support for the ULTRACURVE PRO DEQ2496 to do auto calibrating?

Sure, can add that to the dev list. Will be several weeks before I can get on to it as I have a few more features to add on the measurement side first, but looks to be a useful unit to support.

Regards,
post #74 of 855
Quote:
Originally Posted by JohnPM View Post

Sure, can add that to the dev list. Will be several weeks before I can get on to it as I have a few more features to add on the measurement side first, but looks to be a useful unit to support.

Regards,

Sweet, thank you.


peace
post #75 of 855
John,

Great software! I am just getting my feet wet, learning to use it, and have not attempted to tweak the system based on the results, but that will be coming soon.

But first a nOOb question...

Is it possible to do a manual measurement using Pink Noise? Looks like whenever I engage a manual session, it runs the sin waves, even if the tone generator is set to Pink Noise.

I would think that using sins would be required for parametric work, but talking a snapshot with pink noise would give you a quick look at overall in-room system performance.

Best Regards,

Brian
post #76 of 855
Thread Starter 
Hi Brian,

I guess you are thinking along the lines of an RTA measurement. You will get a faster and much more accurate picture of overall in-room system performance by doing a sweep measurement. The Wizard doesn't provide an RTA display, although it could - can't see the point, though

Regards,
post #77 of 855
Just a couple of quick questions for you guys, first, is there a specific reason why a microphone input on a laptop wouldn't be sufficient? I would imagine it might have something to do with input level or something, but would it not work at all, or just provide inaccurate readings? I would just like to load this onto my laptop for portability's sake, to check out my system's response, as well as a few of my friends' systems. Next question, I am already over budget on my home theater as it is (suprise suprise) and was wondering if there existed some sort of software could open up a soundtrack, apply some equalization to the low end similar to a parametric EQ, then package the soundstream back up to send spdif from my HTPC via optical to my receiver without otherwise molesting the sound, all running in real time. Does anything like this exist, or am I just dreaming?

Thanks for your time guys.
post #78 of 855
Frequency response on mic in is limited, which is why you need to use line in. If you've ever tried to record a turntable on mic in, you'd understand why you cannot use it in this case. It's pretty much designed for vocals...no real high end, and certainly no low end.
post #79 of 855
Thanks avdork, that's kinda what I thought, but I didn't really have anything to back it up.
post #80 of 855
Thread Starter 
V3.22 is now available on the website.

The main functional change in this build is the addition of support for microphone/SPL meter calibration files. The Wizard can load files containing the gain (and optionally phase) characteristics of the measurement device and subtract those from the displayed responses. The response of the mic/meter alone can be displayed by selecting the Mic/Meter Cal trace on the graph panel. If using a C weighted meter the C weighting compensation will still be applied outside the range of the cal file data - e.g. if the cal file data starts at 500Hz, C weighting compensation can still be applied for the region below 500Hz (and the region above the highest frequency in the cal file).

On the measurement side a "Window" control has been added to select the period over which the impulse response is analysed. The default is 600ms, which should work well in most rooms - however smaller rooms may show noisy responses with a 600ms period, if so try reducing it. Chirp Z Transform is now used on the impulse responses to provide frequency response at intervals independent of the FFT length, for measurement spans below approx 2kHz the interval is 0.1Hz, for a full sweep of 10Hz to 20kHz frequency interval it increases to 1Hz. The recommendation for AV processor input sensitivity (where this is adjustable) has been changed from 2V to 0.5V, should reduce the volume settings required for measurement. There are also two bug fixes, C-weighting compensation was not being applied for sweep measurements and the overall level of the sweep measurement was offset if the measurement level was not -18dB (must try harder).

In the User Interface there have been a few rearrangements, partly to make provision for some features to follow in future releases. The main filter control panel has been moved to the right hand side, swapping places with the signal generator panel, and a couple of the options for filter optimisation have moved into the Equaliser menu. There are also new File menu options to save and load a single channel's filter set and a new submenu for exporting data. Preview capability has been added to the file chooser dialogs so you can see information about files before loading them. The results of Find Peaks are now displayed in a table, with the ability to sort the results by amplitude or frequency by clicking in the table header area.

To help people running the Wizard on Macs, which only have a limited implementation of JavaSound, the wave volume control is now active if the Java Sound Audio Engine has ben selected as the output device.

Quite a few other changes, mostly minor, full details on the Revision History page.

Best regards,
post #81 of 855
Thanks John!

I only recently aquired the necessary equipment (microphone, which I had calibrated so this update is timely), mic preamp, USB soundcard, etc.

I'm really looking forward to trying RoomEQ Wizard this evening. I've read through your documentation and it looks incredible. Thank you.

Cary
post #82 of 855
Hello John,

I have a calibrated ETF mic and preamp. If I connect them to your program and use your SPL tool, will I then have a very accurate sound pressure meter? I understand that without another calibrated mic my absolute level will not be exact but if I use the RS meter with calibration pink noise at 75dB my absolute error may be very small??

Thanks,
George
post #83 of 855
Thread Starter 
Hi George,

In absolute terms the result will be as accurate as the initial reference calibration. Use a normal speaker pink noise cal tone to set the reference level against your RS meter, then your calibrated mic will give you accurate spl readings relative to that inital reference from sine wave test tones across the full range of the mic&preamp's response. Remember to disable the C-weighting correction in the Meter menu.

Note that mic calibration values are not applied to the spl reading shown when reading the level of a pink noise source, however, as in that case the spl figure is being directly calculated from the time domain samples.

Regards,
post #84 of 855
Any chance you could generate a .pdf 'user's manual' from all the html help pages? I like having
a printed copy of instructions in front of me when I'm twiddling with apps like this.
post #85 of 855
Thread Starter 
Quote:
Originally Posted by krabapple View Post

Any chance you could generate a .pdf 'user's manual' from all the html help pages? I like having
a printed copy of instructions in front of me when I'm twiddling with apps like this.

I don't know of an easy way to do that (i.e. take a set of HTML pages and make a merged document from them) - I guess could just copy and paste each html file into a Word doc? All of the HTML content is also available directly from the Help within the app, so you can have the help window open on the relevant topic while twiddling. When I've got to the stage where I'm not changing and updating the app so often I'll make some case studies that go through the process from start to end, but at the moment the content would go out of date too quickly.
post #86 of 855
Hello John,
That sounds terrific. Once I calibrate against the RS I should use your program to calibrate the levels for all the speakers and I won't have to worry about the RS correction factor for the sub!
George
post #87 of 855
Nice program, John! It looks like you are adding many of the features of the standalone measurement programs. Can the current version display the impulse response? That's a big help when tracking down HF reflections. That along with the ability to use short windows to get the quasi-anechoic HF response should handle about everything most users would need.
post #88 of 855
Quote:
Originally Posted by JohnPM View Post

I don't know of an easy way to do that (i.e. take a set of HTML pages and make a merged document from them) - I guess could just copy and paste each html file into a Word doc?

Adobe Acrobat might be able to do it -- I'll check and see. If I can do it, I'll send you the pdf. I think it may require extensive html editing to convert inter-file links to intra-file links, before converting to pdf or .doc. My html's a little rusty but I can probably do it.


Quote:


All of the HTML content is also available directly from the Help within the app, so you can have the help window open on the relevant topic while twiddling.

Sorry, I prefer solid paper in hand. Less clutter on the screen. I'm old fashioned that way.

Quote:


When I've got to the stage where I'm not changing and updating the app so often I'll make some case studies that go through the process from start to end, but at the moment the content would go out of date too quickly.

That will be awesome, thanks.
post #89 of 855
Krabapple, just print out the web pages. Let John do more important things like adding features.
post #90 of 855
Thread Starter 
Quote:
Originally Posted by catapult View Post

Can the current version display the impulse response? That's a big help when tracking down HF reflections. That along with the ability to use short windows to get the quasi-anechoic HF response should handle about everything most users would need.

Not yet, but watch this space...
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