# Mac issues with REW



## jlpowell84 (Jan 29, 2013)

Hello HTS! I have always been a AVS guy but I am a HT guy in search of answers so here I am 

I have a newest generation Mac mini. i7 quad core, 16gb ram, 1TB HD, you get it. I have been running REW with my CSL UMM-6 usb mic for almost one year flawlessly. I mean absolute perfect. I also have an Open DRC-AN unit from mini dsp that I use with my dual Seaton Submersives. If you are wondering I went with the Open because I just felt better about XLR in and XLR out. And as a side note it does reduce circuit noise I get to nothing. Anyway I have always measured raw,applied a mini dsp low shelf filter then bypass it, applied mini dsp cuts, ran Audyssey calibration, then un bypassed the mini dsp low shelf filter. And bang I have a nice very smooth bass response with a house curve I can change the steepness of at any time. All this of course after finding optimal location which ended up being the 1/4 and 3/4 points on the front wall. Room is 28x16 with 16 being the width distance on the front wall. Seating is about 10ft from the front wall. There is a dining area behind...

So that is my story and process. Well exactly a month ago I had built room treatments. Reflection panels are 4x24x48 Roxul AFB panels. I have 4 of those then a couple skinnier versions (18 wide) next to each surround. Also a 24x96x2 ceiling treatment with an air gap of a few inches. And it's a rental so I didn't get crazy with bass traps so just two 15x15x48 soffit traps vertically in each corner. Good ol fluffy there. After this I was anxious to get a measurement to see the difference as I was quite familiar with my RAW response. Especially in the 5-150hz bass region. There were improvements, a 60hz null was gone and a generally much smoother response. I then went to the impulse to check my reflection success. This is were the confusion began because I now had -5db reflections all the way out to 40ms? I was very confused as my previous only had one -5db reflection at 10ms which I discovered to be the ceiling and proved it by doing the blocking technique. I held a panel in place using a step ladder, a long stick, and my hand. I then kept my body out of the way and had my wife click go on the sweep. It was a huge difference and was right in line with most people saying the ceiling is the single most beneficially treated area! I was stoked at that time. Anyway the day was late and I gave up. I had come back the next day as I had taken two vacation days to measure after treating. Well I never got anywhere and still haven't. All the sudden my bass response had a giant inverted U shape from 30hz to 250hz that was -42db at its worst! I have spent many nights trying to figure it out and finally un-installed and re-installed REW and SoundFlower. I followed AVS forum member's guide to using SoundFlower as audio pass through. Anyway now I cannot even get a REW SPL meter calibration. I have to take my Denon 4520's MV to 0 to +2db to get my external SPL meter to match what I select as 80db to do the calibration. It was always about -15 on the MV. Now I have a noise floor of 74db! 

Thats it in a nutshell and if anyone has any questions please ask. I am all about solving this and moving forward and contributing in any way I can. I am supposed to help a friend set up his studio/office with a Mac in a few weeks so now I am scrambling. 

Also I have many graphs and pics of my room but if someone could be so kind to instruct me how to post pics on this forum style I will do so.

-Jason


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## gazoink (Apr 17, 2013)

Checked the Mac System Prefs > Sound and Audio Midi Setup? (guessing you did)

What are you doing for a connection from the Mac output to the AVR? Checked the connections? A 15dB drop in level and increase in noise sounds like either a connection or output setting. But it's hard to tell from way over here.

Might try a separate pink noise source, like a test disc, and look at the system using the RTA, just to see if the problem shows up there, or if it's related only to test signals generated from the computer.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> Checked the Mac System Prefs > Sound and Audio Midi Setup? (guessing you did)
> 
> What are you doing for a connection from the Mac output to the AVR? Checked the connections? A 15dB drop in level and increase in noise sounds like either a connection or output setting. But it's hard to tell from way over here.
> 
> Might try a separate pink noise source, like a test disc, and look at the system using the RTA, just to see if the problem shows up there, or if it's related only to test signals generated from the computer.


Can you tell me how to post pics here on HTS 

I have a pic of my RTA and the REW SPL meter. The SPL meter reads 73db while the RTA looks normal around 40db. I have the Mac connected via HDMI. I will check all connections tomm, that is a good idea and I have not done so. Perhaps if it was it seems like it would just be an issue on the Mac connection as movies through the PS3 via HDMI are fine. I did recently sell my Denon 3313, tested a friends Denon X1000 and then got my new Denon 4520. I will even try another HDMI for the of it.

As far as the Audio Midi settings. Is there anywhere that has like a detailed description of what they should be? I am sure they are all right and what they need to be. But it is worth a shot at double checking. I do have a test disc from Mark Seaton that I will try. Perhaps through the Mac and the PS3 for comparison. 

Thank you for your response


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## gazoink (Apr 17, 2013)

jlpowell84 said:


> Can you tell me how to post pics here on HTS


sorry...


jlpowell84 said:


> I have a pic of my RTA and the REW SPL meter. The SPL meter reads 73db while the RTA looks normal around 40db. I have the Mac connected via HDMI. I will check all connections tomm, that is a good idea and I have not done so. Perhaps if it was it seems like it would just be an issue on the Mac connection as movies through the PS3 via HDMI are fine. I did recently sell my Denon 3313, tested a friends Denon X1000 and then got my new Denon 4520. I will even try another HDMI for the of it.
> 
> As far as the Audio Midi settings. Is there anywhere that has like a detailed description of what they should be? I am sure they are all right and what they need to be. But it is worth a shot at double checking. I do have a test disc from Mark Seaton that I will try. Perhaps through the Mac and the PS3 for comparison.
> 
> Thank you for your response


If you're getting any audio at all it's not going to be a physical connection issue or cable issue with HDMI. It may take me a day or two, but I'll hook my Mac to my AVR via HDMI and simulate your issue, if you don't get it fixed first. I'm not near home right now...

Audio Midi output settings should be pretty straight forward, HDMI, 48/24, multichnnel (probably, but you might try 2 channel). 

But for the purposes of calibration, you might consider going into the AVR via analog, one channel at a time. It may make life easier to forget audio over HDMI for a bit, just to get things calibrated. The line out of a Mac is good enough to calibrate with.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> sorry...
> 
> 
> If you're getting any audio at all it's not going to be a physical connection issue or cable issue with HDMI. It may take me a day or two, but I'll hook my Mac to my AVR via HDMI and simulate your issue, if you don't get it fixed first. I'm not near home right now...
> ...


That would be cool! You testing that is  I will double check settings. How do I do the analog hookup to get calibrated? Never done it but would like to to get my system back to calibrated! Feel like I'm missing my usual bass impact 

Do I just get a cable that is 3.5mm headphone jack out of my Mac and then into the appropriate channel via RCA on my AVR?


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## gazoink (Apr 17, 2013)

jlpowell84 said:


> Do I just get a cable that is 3.5mm headphone jack out of my Mac and then into the appropriate channel via RCA on my AVR?


Yes, that's it. However, to look at the total result including the splice you'll need to drive at least the center and lfe simultaneously. "Y" cords work fine.

One comment, though. I would be very surprised that Audyssey alone wouldn't get it right. I assume you have your dual subs connected to the separate sub outputs. If you just run through the standard Audyssey cal, then if you need more bass just adjust both sub trims equally up a few dB, you should be able to hit your goal without any extra dsp. In fact, I'd try that with the extra dsp out of the system first.

I usually suggest an Audyssey Pro cal over extra dsp, given the choice. And the only function I use an outboard sub DSP beyond that is to provide some form of max excursion protection if it's not built in and the subs are not up to doing reference at 20Hz...which most aren't. 

Give me a couple of days on the HDMI audio thing, I'm on the road until late Monday. I find the Mac's handling of all things HDMI to be a tad ragged. One of our iMacs gets the audio wrong every time we plug in the HDMI cable, it routes audio to the iMac speaker and has to be manually changed, sometimes within the player app. But it's an all or nothing deal, and not a level change.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> Yes, that's it. However, to look at the total result including the splice you'll need to drive at least the center and lfe simultaneously. "Y" cords work fine.
> 
> One comment, though. I would be very surprised that Audyssey alone wouldn't get it right. I assume you have your dual subs connected to the separate sub outputs. If you just run through the standard Audyssey cal, then if you need more bass just adjust both sub trims equally up a few dB, you should be able to hit your goal without any extra dsp. In fact, I'd try that with the extra dsp out of the system first.
> 
> ...


Yes Chris K gave me the same advice. Remove the Mini DSP. But my rental home, as I just recently tried because of Chris's advice, puts out a ton of noise in the two Seaton Submersives. I plugged back in the Open DRC Unit with XLR in and out and they were perfectly quite again. So at least I need them hooked up if not filters applied. I always had the thought that the rising hard knee house curve was better than just bumping the sub trim levels. But I am not a seasoned veteran in the audio, calibration, knowing world. It seems the more I learn the less I know and that my perceptions of what is needed are constantly evolving towards less. But I can assuredly say the DSP does not inhibit SQ as another piece in the signal chain. I get massive output down to 9, 10hz in my room.


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## jlpowell84 (Jan 29, 2013)

Okay I have many pics here helping to tell the story.

1. Here is an Impule/ETC showing my reflections. This is prior to the blocking technique I am about to do in the next pic. 
2. This is doing the blocking technique in which the right click method on the Impulse graph showed 4.5 ft reflection at just under 5 MS. It was actually 5ft but pretty close. So this is holding the insulation there and measuring. Looks like a great success! 
3. Here is a post panel, minus the ceiling treatment, RAW response. Not too bad 
4. More RAW response of 5-300.
5. Here is the first sign of weirdness. I always did the mini dsp low shelf then bypass, apply mini dsp cutting filters, run Audyssey, then un bypass my shelf filter for a house curve. After Audyssey the response was always dead flat. And I did it many nights just getting to know the software and have had speaker changes and physical adjustments. But I didn't understand what was happening here and distinctly remember this was the first sign of things heading south.
6. Now the sweeps are just plain crazy
7. Crazy continued 
8. Crazy continued
9. Crazy continued
10. Here is a bass response I had from before I switched my mains from old JBLS to JTR Triple 8's.
11. Full response with the old JBL's


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## JohnM (Apr 11, 2006)

Can you attach mdat files, please?


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## jlpowell84 (Jan 29, 2013)

JohnM said:


> Can you attach mdat files, please?


Yes absolutely! What ones should I attach? and just to be clear is the mdat files attachment under advanced as well?

I have many measurement sessions  But probably the problematic ones?


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## jlpowell84 (Jan 29, 2013)

Just got a reply on AVS that starting a measurement below 20hz caused corrupt measurements. I have always done 5hz just since I have Submersives. I would try but like I have mentioned I cannot even get the REW SPL meter calibrated now. I will check back soon as I am building some speakers today and will be gone for a bit


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## jlpowell84 (Jan 29, 2013)

Just let me know of any info or anything I can post, test or do. I want to help solve this


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## gazoink (Apr 17, 2013)

jlpowell84 said:


> Yes Chris K gave me the same advice. Remove the Mini DSP. But my rental home, as I just recently tried because of Chris's advice, puts out a ton of noise in the two Seaton Submersives. I plugged back in the Open DRC Unit with XLR in and out and they were perfectly quite again. So at least I need them hooked up if not filters applied.


What kind of noise are we talking about? 60Hz hum or something else?


jlpowell84 said:


> I always had the thought that the rising hard knee house curve was better than just bumping the sub trim levels. But I am not a seasoned veteran in the audio, calibration, knowing world. It seems the more I learn the less I know and that my perceptions of what is needed are constantly evolving towards less. But I can assuredly say the DSP does not inhibit SQ as another piece in the signal chain. I get massive output down to 9, 10hz in my room.


Generally, hard knees in a curve are not desirable. It's not a smooth transition, and to create a sharp knee will result in unnecessary phase shift around the break point. It's not a huge deal, but smooth is usually better.

Since you're using dual subs, have you tried a response test with one disconnected, or with a phase flip on one?


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## gazoink (Apr 17, 2013)

Since you're using a USB mic and HDMI out, you might check out this:
http://johnr.hifizine.com/2013/02/room-eq-wizard-on-the-mac-an-input-workaround/

HDMI as an audio out qualifies as a multichannel sound device, and the UMM-6 is definitely an issue.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> What kind of noise are we talking about? 60Hz hum or something else?
> 
> 
> Generally, hard knees in a curve are not desirable. It's not a smooth transition, and to create a sharp knee will result in unnecessary phase shift around the break point. It's not a huge deal, but smooth is usually better.
> ...


Yea like a 60hz humm but VERY loud. One guy on Submersive forum had success with a high quality audio outlet. I forget the name but it eliminated his buzzing. 

I have tried phase flip via the mini dsp screen that has a polarity button.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> Since you're using a USB mic and HDMI out, you might check out this:
> http://johnr.hifizine.com/2013/02/room-eq-wizard-on-the-mac-an-input-workaround/
> 
> HDMI as an audio out qualifies as a multichannel sound device, and the UMM-6 is definitely an issue.


I will check that link out soon. The thing is everything that is all in the exact same place and REW on my Mac Mini and my UMM-6 had worked flawless for almost a year. So the big mystery is why now? I honestly have a suspicion there may have been some kind of update or my mic went bad. The mic I will test elsewhere soon. 

I also thought just for the of it installing the older version of REW to try it.

Also a side note is my mic has never been dropped or even banged. Always treated like a feather.


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## EarlK (Jan 1, 2010)

jlpowell84 said:


> I will check that link out soon. The thing is everything that is all in the exact same place and REW on my Mac Mini and my UMM-6 had worked flawless for almost a year. So the big mystery is why now? I honestly have a suspicion there may have been some kind of update or my mic went bad. The mic I will test elsewhere soon.
> 
> I also thought just for the of it installing the older version of REW to try it.
> 
> Also a side note is my mic has never been dropped or even banged. Always treated like a feather.


If ( your only systemic change ) is that you recently "updated" your OS to Mavericks then I would suggest that changing your OS is cause of your newly acquired issues ( ie; inconsistent measurements ) .

To test that theory, partition your hard-drive , reinstall 10.8 onto the new partition ( as well as REW ) and "boot & run " REW from that partition .

:sn:


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## jlpowell84 (Jan 29, 2013)

EarlK said:


> If ( your only systemic change ) is that you recently "updated" your OS to Mavericks then I would suggest that changing your OS is cause of your newly acquired issues ( ie; inconsistent measurements ) .
> 
> To test that theory, partition your hard-drive , reinstall 10.8 onto the new partition ( as well as REW ) and "boot & run " REW from that partition .
> 
> :sn:


Ok. I actually sold my Sherbourn PA 7350 amp and Denon 3313 and Changed to just a Denon 4520. Amplification should not make any differences, especially since the subs have their own


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## gazoink (Apr 17, 2013)

jlpowell84 said:


> Yea like a 60hz humm but VERY loud. One guy on Submersive forum had success with a high quality audio outlet. I forget the name but it eliminated his buzzing.
> 
> I have tried phase flip via the mini dsp screen that has a polarity button.


The 60Hz is a ground loop issue. If you want to try to eliminate it there are several things to try. Check the unbalanced cable you're using to make sure it's good. If you're using an RCA to XLR cable, check how it's wired. If the cable is good, try lifting the ground on both subs. You can do this with a 3-prong to 2-prong AC adapter on each. 

There's a few more things to try, but lets start there.

On the REW sound issue, what OS version are you using? As posted before, there are issues with Java sound, and they get worse with later OS versions. I did test REW on OSX 10.7.5 with on-board sound, that works fine. Later I'll test it with a multi-channel external device, and if you're patient, I'll get to testing REW with an HDMI sound device. And I have a machine on Mavericks I can also try. I don't have the USB mic.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> The 60Hz is a ground loop issue. If you want to try to eliminate it there are several things to try. Check the unbalanced cable you're using to make sure it's good. If you're using an RCA to XLR cable, check how it's wired. If the cable is good, try lifting the ground on both subs. You can do this with a 3-prong to 2-prong AC adapter on each.
> 
> There's a few more things to try, but lets start there.
> 
> On the REW sound issue, what OS version are you using? As posted before, there are issues with Java sound, and they get worse with later OS versions. I did test REW on OSX 10.7.5 with on-board sound, that works fine. Later I'll test it with a multi-channel external device, and if you're patient, I'll get to testing REW with an HDMI sound device. And I have a machine on Mavericks I can also try. I don't have the USB mic.


I have tried different cables and the cheater plugs as well. Someone on the Seaton Submersive forum had success with his by buying a high end receipt from an audio company.


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## gazoink (Apr 17, 2013)

jlpowell84 said:


> I have tried different cables and the cheater plugs as well. Someone on the Seaton Submersive forum had success with his by buying a high end receipt from an audio company.


You may not want to bother with this because you already have a "fix". But just in case...

First thing to establish is if you have the subs and 4520 on the same AC phase. Breaker boxes put adjacent breakers on opposite phases so you can put in a double breaker for 220V devices. Breakers on opposite sides are also on opposite phases. You want all your gear on the same phase for minimum hum issues.

Assuming that's done, you need to disconnect everything from the AVR but the speakers and subs, connect the subs using an unbalanced cable and observe the hum. If it's still bad, try lifting the third pin ground on the subs (both) then the AVR too. You should find a combination that minimizes the hum. Once you find that, reconnect each device one at a time and observe the hum. One device with a ground issue is all it take to create a system-wide hum. This includes source devices and displays and projectors. If there's an offending device, you can work on grounding (or floating) that one. 

All a high-end AC connector could ever do is some filtering, and cases where line noise is the probably are quite rare. It might also provide a better ground connection, but "better" would indicate a defective standard outlet, not some magic in the high-end unit.

Back to the Mac/REW issue, it seems there are problems with REW on Mavricks, so we need to establish which OS version you're on to proceed.


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## jlpowell84 (Jan 29, 2013)

gazoink said:


> The 60Hz is a ground loop issue. If you want to try to eliminate it there are several things to try. Check the unbalanced cable you're using to make sure it's good. If you're using an RCA to XLR cable, check how it's wired. If the cable is good, try lifting the ground on both subs. You can do this with a 3-prong to 2-prong AC adapter on each.
> 
> There's a few more things to try, but lets start there.
> 
> On the REW sound issue, what OS version are you using? As posted before, there are issues with Java sound, and they get worse with later OS versions. I did test REW on OSX 10.7.5 with on-board sound, that works fine. Later I'll test it with a multi-channel external device, and if you're patient, I'll get to testing REW with an HDMI sound device. And I have a machine on Mavericks I can also try. I don't have the USB mic.


10.9.2


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