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Finally measuring time! 8 FTWs and 2 Mal 21s. Need help - Page 3

post #61 of 128
3/1/13 at 5:28am
How about trying the "pseudo noise" track, I believe it's track 1. It's easier on the ears, you need to check the "pseudo noise" box next to the "sine sweep" box.

I use head-worrn hearing protection during extended response testing, as you're absolutely right,.. it gets annoying.

The sine wave testing is a must for the upper freqs, but the noise track is fine for sub testing/sub to mains blending, etc.
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post #62 of 128
3/1/13 at 7:07am
I had the same problem with omnimic myself and finally bought a calibrated behringer mic and used REW. I think once you have a sound card and mic all setup REW is easier but it takes much more to get it going.
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post #63 of 128
3/1/13 at 7:14am
Quote:
Originally Posted by audiovideoholic View Post

Quote:
Originally Posted by beastaudio View Post

Seeing your response extend below 12hz as it should, if you are down, I would love to pay to have you send me your entire OM rig so I can see if I still have the same response drop-off that I am still seeing through two different mics. That way I could clear any issues with the additional measuring rig I use. If you are down, and when you are done that is smile.gif

What do you mean by extend below 12hz? Like your measurements aren't? I wouldn't mind loaning it. What are you using now, rew?

I have used OM v1, uncalibrated, and REW with the UMM-6 calibrated from CSL and they both show an identical drop at about 11-12hz, which is also identical to what I have measured on every single build that I have done, and on three different AVR's. It is frustrating, with 8 sealed 18's there is no way I should show the same drop-off that I do, but should I measure with your mic that obviously measures fine below 10hz, then I could at least cross the mics being the issue off my list biggrin.gif haha
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post #64 of 128
3/1/13 at 7:40am
Quote:
Originally Posted by beastaudio View Post

I have used OM v1, uncalibrated, and REW with the UMM-6 calibrated from CSL and they both show an identical drop at about 11-12hz, which is also identical to what I have measured on every single build that I have done, and on three different AVR's. It is frustrating, with 8 sealed 18's there is no way I should show the same drop-off that I do, but should I measure with your mic that obviously measures fine below 10hz, then I could at least cross the mics being the issue off my list biggrin.gif haha

It is most likely your electronics dropping off. Think about this, if your AVR is -3 dbs at 5hz, DCX is -3 dBs at 5hz, bluray player, -3 dbs at 5hz, amp -3 dbs at 5hz, sound card -3 dBs at 5hz, and mic is -3 dBs at 5hz you would get -18 dBs at 5hz! I don't care what subs you have you will not be flat to 5hz. These calibrated mics are pretty good to 4hz from CSL so it has to be your electronics rolloff adding up.
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post #65 of 128
3/1/13 at 9:23am
Quote:
Originally Posted by MKtheater View Post

I had the same problem with omnimic myself and finally bought a calibrated behringer mic and used REW. I think once you have a sound card and mic all setup REW is easier but it takes much more to get it going.

Wow, I respectfully disagree.

In my opinion, nothing is as easy as OmniMic.

Quote:
Originally Posted by beastaudio View Post

I have used OM v1, uncalibrated, and REW with the UMM-6 calibrated from CSL and they both show an identical drop at about 11-12hz, which is also identical to what I have measured on every single build that I have done, and on three different AVR's. It is frustrating, with 8 sealed 18's there is no way I should show the same drop-off that I do, but should I measure with your mic that obviously measures fine below 10hz, then I could at least cross the mics being the issue off my list biggrin.gif haha


Does the level return below the 11hz-12hz range? If so ... I've seen this before myself, in my room, and have seen it elsewhere too. Also, I've seen measurements with similar characteristics. I've always suspected some type of diaphragmatic lossy movement of my ceiling ... single story ranch .. above my listening room is my attic. I've discussed my findings with Josh Ricci, and he's had similar suspicions in many of his measurements.

Mine is fairly tightly focused, around 11hz-12hz, then the levels come back up until 7hz-8hz, then the entirety of all the collective signal path roll-offs, combined with the drivers etc, dropping off from there. It's never been more than a scientific concern, no biggie really.

So, that said I'm not sure what causes the anomalous behavior in my room, ... hell, there's times I couldn't get it to happen, .. so who knows.

If the boundary becomes lossy, sympathetically moving, that's certainly utilizing energy that otherwise would be impacting the listener.


My 2 cents.

edit; I may have misunderstood a suck-out, for a drop off
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post #66 of 128
3/1/13 at 9:29am
Quote:
Originally Posted by MKtheater View Post

Quote:
Originally Posted by beastaudio View Post

I have used OM v1, uncalibrated, and REW with the UMM-6 calibrated from CSL and they both show an identical drop at about 11-12hz, which is also identical to what I have measured on every single build that I have done, and on three different AVR's. It is frustrating, with 8 sealed 18's there is no way I should show the same drop-off that I do, but should I measure with your mic that obviously measures fine below 10hz, then I could at least cross the mics being the issue off my list biggrin.gif haha

It is most likely your electronics dropping off. Think about this, if your AVR is -3 dbs at 5hz, DCX is -3 dBs at 5hz, bluray player, -3 dbs at 5hz, amp -3 dbs at 5hz, sound card -3 dBs at 5hz, and mic is -3 dBs at 5hz you would get -18 dBs at 5hz! I don't care what subs you have you will not be flat to 5hz. These calibrated mics are pretty good to 4hz from CSL so it has to be your electronics rolloff adding up.

I would agree, but that simply isn't the case. The LG14k has minimal rolloff, and the 4311 and the marantz 8801 are both tested to be pretty darn flat. Keep in mind my rolloff is happening above 10hz, not 5hz. Without a BD player OR the DCX in the chain, the rolloff is identical as it is using both, so that is strange as well. If adding two additional pieces to the chain and I still get identical rolloff, makes me think it is elsewhere. I don't care if I am flat to 5hz (I mean that would be cool though), I care that I am flat to 10hz, maybe even 7hz if I am lucky, that is all I want. People with less than 8 SI's are even measuring more extension than I am at the moment.
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post #67 of 128
3/1/13 at 9:30am
FOH,
You need to understand my setup.

Running Omnimic:
Place CD in bluray
setup labtop in a seat
Plug in mic and place in LP
Run CD and OM, done.

Running REW:
Set up mic at LP first
Go to computer(where the bluray player is) and run sweep, done

I will repeat, everything is already done, calibrating and setup of soundcard, etc... Initial setup the Omnimic just adds software install so that is obviously easier at first.
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post #68 of 128
3/1/13 at 9:33am
Quote:
Originally Posted by FOH View Post

Quote:
Originally Posted by MKtheater View Post

I had the same problem with omnimic myself and finally bought a calibrated behringer mic and used REW. I think once you have a sound card and mic all setup REW is easier but it takes much more to get it going.

Wow, I respectfully disagree.

In my opinion, nothing is as easy as OmniMic.

Quote:
Originally Posted by beastaudio View Post

I have used OM v1, uncalibrated, and REW with the UMM-6 calibrated from CSL and they both show an identical drop at about 11-12hz, which is also identical to what I have measured on every single build that I have done, and on three different AVR's. It is frustrating, with 8 sealed 18's there is no way I should show the same drop-off that I do, but should I measure with your mic that obviously measures fine below 10hz, then I could at least cross the mics being the issue off my list biggrin.gif haha


Does the level return below the 11hz-12hz range? If so ... I've seen this before myself, in my room, and have seen it elsewhere too. Also, I've seen measurements with similar characteristics. I've always suspected some type of diaphragmatic lossy movement of my ceiling ... single story ranch .. above my listening room is my attic. I've discussed my findings with Josh Ricci, and he's had similar suspicions in many of his measurements.

Mine is fairly tightly focused, around 11hz-12hz, then the levels come back up until 7hz-8hz, then the entirety of all the collective signal path roll-offs, combined with the drivers etc, dropping off from there. It's never been more than a scientific concern, no biggie really.

So, that said I'm not sure what causes the anomalous behavior in my room, ... hell, there's times I couldn't get it to happen, .. so who knows.

If the boundary becomes lossy, sympathetically moving, that's certainly utilizing energy that otherwise would be impacting the listener.


My 2 cents.

edit; I may have misunderstood a suck-out, for a drop off

yea, it isn't a suckout, it is a cliff, and it stinks...I need to run the test disc more and see what the RS meter reads with some low frequency tones to see if I can confirm it there too...
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post #69 of 128
3/1/13 at 9:34am
It has to be the room or you are not doing something right with the mic calibrations. I say not the room because with sealed subs you should be rolling off at 12 dBs or less per octave in room. You are rolling off far more than that. Do you know what the responses really are for your gear? I know the 14K is not the culprit as it is -3 at 2hz. I have high end components and they have little rolloff but my soundcard rolls off at 10 dBs at 5hz! So I am still getting the low stuff but my graphs will never show the true deep bass unless I change the soundcard. My mic is calibrated to 4hz.
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post #70 of 128
3/1/13 at 9:58am
Quote:
Originally Posted by MKtheater View Post

It has to be the room or you are not doing something right with the mic calibrations. I say not the room because with sealed subs you should be rolling off at 12 dBs or less per octave in room. You are rolling off far more than that. Do you know what the responses really are for your gear? I know the 14K is not the culprit as it is -3 at 2hz. I have high end components and they have little rolloff but my soundcard rolls off at 10 dBs at 5hz! So I am still getting the low stuff but my graphs will never show the true deep bass unless I change the soundcard. My mic is calibrated to 4hz.
Hey MK, That is the real Lab Gruppen, has the Clone been tested to be good to 2hz?
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post #71 of 128
3/1/13 at 10:01am
I think Bosso has shown that it is flat down low. I know I have less rolloff than ever.
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post #72 of 128
3/1/13 at 10:18am
Quote:
Originally Posted by MKtheater View Post

FOH,
You need to understand my setup.

Running Omnimic:
Place CD in bluray
setup labtop in a seat
Plug in mic and place in LP
Run CD and OM, done.

Running REW:
Set up mic at LP first
Go to computer(where the bluray player is) and run sweep, done

I will repeat, everything is already done, calibrating and setup of soundcard, etc... Initial setup the Omnimic just adds software install so that is obviously easier at first.


smile.gif


Both systems require setting up a mic, opening and using a computer program.
So, the extra work includes;
1.) placing the CD in the player
2.) inserting a USB connector

You're right, REW appears easier rolleyes.gif
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post #73 of 128
3/1/13 at 11:25am
Only because my computer and REW is always on and all I have to do is place the mic. Omnimic requires me to get a labtop or I could buy an extender for their cord so I can use the same computer and do the same thing. I am just saying once REW is setup it is very fast and easy every time. Saves me a whole 2-3 minutes! Now for someone just getting started omnimic is much faster.
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post #74 of 128
3/1/13 at 12:02pm
Calibration or the soundcard could easily be the issue, but I was under the impression that the USB mics didn't use the soundcard, at least that is what I read. I don't quite see how that is possible though. I plan on getting a new laptop in the next little bit tho so perhaps I should just take some suggestions for that instead biggrin.gif I am looking at something cheap as my main laptop is my macbook, this one basically be a itunes hub, and testing rig smile.gif I see the Acers have dolby tech in them, and just about everything has HDMI these days, so it shouldn't be too hard to find something.
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post #75 of 128
3/1/13 at 1:01pm
My vote is calibration...
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post #76 of 128
3/1/13 at 3:02pm
Thread Starter 
Well, I'm about ready to throw both the mic and dsp in a fire!!!! I've measured and changed settings for about 10-12hours and am still nowhere near my goal of either A) getting rid of my mountain from 45-75hz or B) boosting to match the mountain.

I can get close with the distortion long sweep, so close that I'd be perfectly happy but I know that once I change to FR tool ill have a 10+db drop at 30hz and mountain right after it. I've tried using everything I have to work with phase, delay, peak EQ, sub EQ, and Q. I'm getting nowhere with this minidsp and not fast! I have the volume situation fixed by using two desperate rcas for in and out but that about it.

I'm going to start all over and post the graphs and see if any of you wise people can help get this figured out. I'm also going to take measurements at one meter just to see what's going on.

I'm not getting terrible roll off until under 8hz or so but still down a little more than expected although nothing is going as expected right now.

I'm wondering if under the PEQ settings on the mini what is the best option to use to make audible changes as I'm not really having much luck with "peak eq" or "sub eq" and sub eq is limited to 50hz max and I have problems above that. I have seen some audible changes when upped the "Q" but not enough to fix my mountain or valley.
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post #77 of 128
3/1/13 at 3:10pm
Did I miss something? The last posted FR graph you put up looked pretty good save for a dip in the chest punchy region.

Maybe you just need mains that are more impressive in that region. Hahah, jk....sort of. wink.gif

Maybe a couple 2242's or TD18's right in the middle where the gap is would bring on the punch! smile.gif
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post #78 of 128
3/1/13 at 3:21pm
Thread Starter 
Quote:
Originally Posted by Scott Simonian View Post

Did I miss something? The last posted FR graph you put up looked pretty good save for a dip in the chest punchy region.

Maybe you just need mains that are more impressive in that region. Hahah, jk....sort of. wink.gif

Maybe a couple 2242's or TD18's right in the middle where the gap is would bring on the punch! smile.gif

Oh, I'm perfectly happy with what I've been able to measure using the distortion tool with long sweeps but FOH said that the FR tool is more accurate and when I use it along with the short sweeps it calls for the graphs are awful. Ill post up the pics to show the difference later. I've managed to get the distortion measurements even better than what have posted but FR tool graphs have showed it being even worse so just erased and kept moving along.

Yeah, if I had some huge mains I'd be much better off. Should have just built some and paid for crossover work. Like triple 15s each or something lol. No room to switch out the jtrs now unless rebuilt whole baffle wall.
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post #79 of 128
3/1/13 at 11:11pm
Thread Starter 
OK. Here are close mic and first row measurements with both frequecny response tool with fast sweeps and distortion tool with long sweeps with eq flat

close mic distortion with invert
[URL=http://][/URL]

close mic FR with invert
[URL=http://][/URL]

Front row FR with invert
[URL=http://][/URL]

Front row Distortion invert
[URL=http://][/URL]

Noise floor
[URL=http://][/URL]

I have no idea why the graphs changed from 10hz start to 20hz start sometimes. Will remeasure tomorrow with same graph start. Maybe someone will see something from these.

Front row no invert
[URL=http://][/URL]

I am going to add a graph of the last config before going back to flat just to show what a boost of +4db at 10hz and +3db at 15hz does inverted.
[URL=http://][/URL]
Edited by audiovideoholic - 3/1/13 at 11:24pm
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post #80 of 128
3/2/13 at 8:43am
I'd recommend not bothering w/the distortion measurements now.

Also,when examining the LF, the parameters need to change to limit the top end to 200hz, the bottom can be whatever you want, 10hz, 5hz.

I'd also suggest you close mic, just for a sanity check. Place the mic right up within 3" of one of the subs, use the first track, the pseudo noise track, use hearing protection so it's not so annoying. You can do without ear plugs, but it makes it more tolerable long term.

Once the graph parameters are set, they don't change.

If you could post the close mic'd graph, that'd be a good indicator of the overall system/measuring rig picture, then we'd know if everything else is cool to proceed. The shape of the close mic'd measurement should be telling. Ideally, it'd be a nice big arc.

If you had the time, that would be helpful, and it shouldn't take much time.
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post #81 of 128
3/2/13 at 11:38am
Thread Starter 
Quote:
Originally Posted by FOH View Post

I'd recommend not bothering w/the distortion measurements now.

Also,when examining the LF, the parameters need to change to limit the top end to 200hz, the bottom can be whatever you want, 10hz, 5hz.

I'd also suggest you close mic, just for a sanity check. Place the mic right up within 3" of one of the subs, use the first track, the pseudo noise track, use hearing protection so it's not so annoying. You can do without ear plugs, but it makes it more tolerable long term.

Once the graph parameters are set, they don't change.

If you could post the close mic'd graph, that'd be a good indicator of the overall system/measuring rig picture, then we'd know if everything else is cool to proceed. The shape of the close mic'd measurement should be telling. Ideally, it'd be a nice big arc.

If you had the time, that would be helpful, and it shouldn't take much time.

There is a close mic graph above (2nd one I just posted). Will change top limit next time am out there but think it looks pretty close to normal. Note that it was taken with subs inverted but the measurements look almost identical inverted or not.
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post #82 of 128
3/3/13 at 9:09pm
Thread Starter 
OK, here are all 8 measured at aprox 3 inch in order from right to left

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

[URL=http://][/URL]

Not much difference but can see a little between the first 4 compared to the last 4 which are on different amp and different enclosure. But I dont see anything that would cause the other graphs to look the way they do. Anything?
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post #83 of 128
3/3/13 at 9:30pm
Thread Starter 
Here are some random graphs where I tried to find the optimal placement of the mic and only found one spot in the entire room where it produced a somewhat smooth FR. Here it is and it was aprox three foot in front of right front row seat right edge of seat as well. Note that when I measured at the opposite place on the left side of the room I ended up with the same ole funky graph as in the seating positions. I measured in about 15-20 places and all produced the same humps. Got curious and measured up high and low while still getting the same results.

Best one
[URL=http://][/URL]

Opposite of best location front row left seat edge up three foot
[URL=http://][/URL]

Seating front row position no changes
[URL=http://][/URL]

Seating second row no changes
[URL=http://][/URL]

Now that we can see that the subs have a decent curve by themselves at close mic but room is acting crazy in pretty much all locations when they are all combined except for that one spot up three foot from the right edge of the front row's right seat, what to do now? I wonder if my room is too stiff? I would be willing to bet that my walls and ceiling have less flex than 90% of stick framed theaters. Just throwing that out there even though it may have absolutely nothing to do with it.
Edited by audiovideoholic - 3/3/13 at 9:39pm
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post #84 of 128
3/4/13 at 6:56am
The close mic graphs look good.

Place the mic at the primary listening position, and smooth the response with EQ (or automated Audyssey). If manually EQ'ing, always knock down the peaks, and typically, never boost the narrow dips.

You'll be fine. Now you've also got plenty of headroom for boosting the LF/ULF to overcome some of the native roll-off.

Are you going to use Audyssey, or similar automated tool?
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post #85 of 128
3/4/13 at 2:36pm
Well that could be a problem... what the heck is that 85db at 60hz? eek.gif


I wonder, that if by making the close-mic measurments flatter; the room would measure a bit flatter too. Like what happens when you cut 30 to 80hz down by 10db and then boost the input by say 5db?
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post #86 of 128
3/4/13 at 4:58pm
Quote:
Originally Posted by BassThatHz View Post

I wonder, that if by making the close-mic measurements flatter; the room would measure a bit flatter too.

Nope

The close mic appears that way because the direct energy off the cone takes the "room" out of the equation,...actually lessening it's relative significance.

The same gentle arc response of a close mic measurement, typically extends out nicely with the PVG added back in. However, the room's influences also corrupt the response,..introducing constructive peaks, and destructive dips. That's the big advantage of the close mic graph, it's akin to a sanity check ... because it should typically appear like that.
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post #87 of 128
3/4/13 at 6:24pm
"Well that could be a problem... what the heck is that 85db at 60hz?"

i was wondering if the 60hz problem is grounding/power related electrical problem.

the close mic response all look great though, so maybe it is something else, perhaps something rattling in the room or hvac being picked up by mic?

the fact that it is labeled "noise floor" has me concerned because that peak is going to mess up all the other room measurements. that peak must be figured out and removed as the first step.
Edited by LTD02 - 3/4/13 at 6:32pm
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post #88 of 128
3/4/13 at 7:11pm
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"Well that could be a problem... what the heck is that 85db at 60hz?"

i was wondering if the 60hz problem is grounding/power related electrical problem.

the close mic response all look great though, so maybe it is something else, perhaps something rattling in the room or hvac being picked up by mic?

the fact that it is labeled "noise floor" has me concerned because that peak is going to mess up all the other room measurements. that peak must be figured out and removed as the first step.

It's a hum that appears when I hook up any pro amp that I have. It is present with three different avrs in three different rooms which are all separate circuits and one being a completely different electrical system. I agree that it needs to go but after taking close mic measurements and finding a spot in the room that is flat I don't think it's causing the hump to be spread out so far. I personally cannot hear the hum how the system is set right now. If I turn gains up higher I can hear it. None of the hum comes from surrounds just LCRs and subs. I had it gone for one day by wire management and then it was back the next time I turned everything on so really will have to just unhook every wire and try to trace it again.

I just don't know where to start with the EQ as I literally tried different settings over and over for more than 10 hours easily without any luck. Will post settings of EQ at attempts and show results. I'll first try to cut unless someone thinks boosting low end would be better.
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post #89 of 128
3/4/13 at 7:22pm
Thread Starter 
Quote:
Originally Posted by FOH View Post

Nope

The close mic appears that way because the direct energy off the cone takes the "room" out of the equation,...actually lessening it's relative significance.

The same gentle arc response of a close mic measurement, typically extends out nicely with the PVG added back in. However, the room's influences also corrupt the response,..introducing constructive peaks, and destructive dips. That's the big advantage of the close mic graph, it's akin to a sanity check ... because it should typically appear like that.

This is what pi$$es me off the most. I know it's the room combined with too many subs across the stage and was warned by Dennis E when he designed the room not to put them all up there. I used the golden ratio as the room layout and should have listened to the pro designer but have seen too many people with multiple subs like my setup. Guess I just happen to be one that measured lol. It sounds great to the untrained ear and I could barely notice the hump with audyssey in place. May use it just to see what it does and then start with EQ afterwards, think that's a good idea?

I've just never had this much of a problem with a dsp but have only used them in high end auto stereos with multiple amps and subs and have had high output voltages in both setups This is first time using mic with measuring software but have been able to use mics and test discs with dsps with good results. I guess there is big difference between cabin gain and room gain is all I can think of or my mini dsp is defective. The dip should be easy enough to smooth but I promise it's not happening. When can get out there I'll post findings with settings.
Edited by audiovideoholic - 3/4/13 at 7:33pm
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post #90 of 128
3/4/13 at 8:26pm
actually, after overlaying the close mic response (red) over the room response, things don't actually look that bad.

you are not getting much room gain at all, so perhaps adding some boost to the low end might be a good place to start.



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