Simplified REW Setup and Use (USB Mic & HDMI Connection) Including Measurement Techniques and How To Interpret Graphs - Page 124 - AVS Forum
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post #3691 of 12052 Old 06-18-2013, 06:42 AM
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I guess I just expected more from the room mode guru! biggrin.gif
Doh! Sorry to disappoint, but I don't get to choose effective subwoofer locations (your charts do).

 

Well, I could argue I have you to blame (or thank, such a fine line in this case) for the 30Hz ringing since your first placement recommendation didn't resolve the larger issue!  It's not like I had any placement constraints! tongue.gif

 

L+R+Sub where blue was before with sub in right corner and red was after locating sub to the mid front wall:

 

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post #3692 of 12052 Old 06-18-2013, 06:48 AM
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@Keith,

What advice did you receive from Sanjay WRT sub placement that resulted in the improvement?

 

I gave Sanjay mty room dimensions and some photos showing the limitations of what options I have or don't have. Sanjay kindly suggested that I move the subs from their contemporary locations and experiment moving them a foot at a time and then 6 inches at a time, using REW as my guide as I went along. This enabled me to find some alternative locations that helped smooth the bass quite a bit. (Incidentally, the locations have only been made possible by the ever-angelic Mrs Keith consenting to my permanently blocking one of the two doors into the room). 

 

The subs were originally: Sub 1 in right hand corner, Sub 2 just off halfway along the left side wall. They are now both along their respective side walls, facing each other, about 1/4 of the distance (guessing) from the front wall (1/4 of the side wall length I mean).  I was also able to make some changes to the bass traps once the sub had been moved out of the corner but this would probably have had only a minor effect.

 

Once that was done, Sanjay suggested that it would be possible now to move the L and R speakers to 21 inches from the side walls (measured to the centre of the woofers). The combination of these suggestions has resulted in the L+R+Subs waterfall I just posted. I am a very happy bunny. And these improvements came at a cost of precisely $0 too!  

 

Did you also notice these improvements in your FR?

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post #3693 of 12052 Old 06-18-2013, 07:58 AM
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Originally Posted by AustinJerry View Post

Markus,

I think you missed the point of my question.  We know that excessive bass ringing in the 40-80Hz range can result in bloated, one-note bass, which can make music quite unpleasant.  But what does ringing below 40Hz sound like?  Is the ringing really unpleasant when all it affects is movie sound track effects?

I am at a decision point.  My bass ringing is reasonably controlled down to 40Hz.  Can I move on to work on taming specular reflections, or must I exert more effort on the below 40Hz modal region?



This is what I got, and for 2 ch audio, I find it acceptable. I think sometimes we get more keyed to what the graph looks like than what it sounds like.

Something to keep in mind is that at very low frequencies, your not dealing with source material that has sharp attacks. At 50hz, you have the kick drum. And if you had a ringing problem there, the kick, being a fairly sharp cut, would muddy up. Below 40hz, I dont find slow decays or a certain amount of ringing as urgent. Not saying it good, just not top priority.

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post #3694 of 12052 Old 06-18-2013, 08:33 AM
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Originally Posted by Saturn94 View Post

This evening I went through the steps in the REW guide to create a waterfall graph and decay rate graph. I also took new measurements lowering the sub level 2.5db and 5db. For reference, this is for the L+R+Sub, HP filter in pre/pro set to 100hz, LP filter set to 80hz.

Sub lowered 2.5db and 5db (1/6 smoothing)


Waterfall (sub down 2.5db);


Decay (sub down 2.5db);


Something I didn't mention in my previous post with my speaker details, the Soundfield Audio Monitor 1 is a 3 way with a passive coax mid/tweeter and a powered "sub" (crossover from mid to sub is at 200hz, 1st order). Since the "subs" in the L&R speakers have their own amps, I can independently adust the level of each. Another day I'll do some experimenting with those levels to see what happens.

So how do these new graphs look? Do they look like I did them properly?

Thanks. smile.gif

I'm afraid my post might have been lost in this fast moving thread. Any feedback on what in looking at here is appreciated as I'm just learning how to take measurments and interpret the results.

Btw, someone asked if I use EQ. I do not have any EQ or room correction software/device available. I'm considering getting something like the miniDSP if it would make a significant SQ improvement.

Thanks. smile.gif

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post #3695 of 12052 Old 06-18-2013, 09:07 AM
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Quote:
Originally Posted by jkasanic View Post

Quote:
Originally Posted by kbarnes701 View Post

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Originally Posted by AustinJerry View Post

@Keith,

What advice did you receive from Sanjay WRT sub placement that resulted in the improvement?

 

I gave Sanjay mty room dimensions and some photos showing the limitations of what options I have or don't have. Sanjay kindly suggested that I move the subs from their contemporary locations and experiment moving them a foot at a time and then 6 inches at a time, using REW as my guide as I went along. This enabled me to find some alternative locations that helped smooth the bass quite a bit. (Incidentally, the locations have only been made possible by the ever-angelic Mrs Keith consenting to my permanently blocking one of the two doors into the room). 

 

The subs were originally: Sub 1 in right hand corner, Sub 2 just off halfway along the left side wall. They are now both along their respective side walls, facing each other, about 1/4 of the distance (guessing) from the front wall (1/4 of the side wall length I mean).  I was also able to make some changes to the bass traps once the sub had been moved out of the corner but this would probably have had only a minor effect.

 

Once that was done, Sanjay suggested that it would be possible now to move the L and R speakers to 21 inches from the side walls (measured to the centre of the woofers). The combination of these suggestions has resulted in the L+R+Subs waterfall I just posted. I am a very happy bunny. And these improvements came at a cost of precisely $0 too!  

 

Did you also notice these improvements in your FR?

 

The FR was pretty good to start with. It's still pretty good now so I can't say whether it's better now than it was before or not. Either way, I'm happy with it (for now). My ETCs are slightly worse though - I have more work to do there once I have the PJ and screen installation and setup out of the way. 

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post #3696 of 12052 Old 06-18-2013, 09:12 AM
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Originally Posted by Saturn94 View Post

I'm afraid my post might have been lost in this fast moving thread. Any feedback on what in looking at here is appreciated as I'm just learning how to take measurments and interpret the results.

Btw, someone asked if I use EQ. I do not have any EQ or room correction software/device available. I'm considering getting something like the miniDSP if it would make a significant SQ improvement.

Thanks. smile.gif

 

In terms of your waterfall and bass decay, the nulls between 50 and 60 Hz (and 100-110Hz) is the only real issue I see.  Shows up a little more on the bass decay than on the waterfall.  Considering you don't have any treatments or EQ, the FR isn't too bad either.  Have you posted any info on your room and current speaker locations?  Using the room mode calculator will show you where your axial modes lie.  Is the length or width of your room approx. 10.5'?  That could explain some of your issues between 50-60Hz (1st order) and 100-110Hz (2nd order) especially if modifying the crossover and sub delay didn't have much impact (assuming you already tried changing them per Jim's suggestion?).

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post #3697 of 12052 Old 06-18-2013, 09:49 AM
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Originally Posted by jkasanic View Post

In terms of your waterfall and bass decay, the nulls between 50 and 60 Hz (and 100-110Hz) is the only real issue I see.  Shows up a little more on the bass decay than on the waterfall.  Considering you don't have any treatments or EQ, the FR isn't too bad either.  Have you posted any info on your room and current speaker locations?  Using the room mode calculator will show you where your axial modes lie.  Is the length or width of your room approx. 10.5'?  That could explain some of your issues between 50-60Hz (1st order) and 100-110Hz (2nd order) especially if modifying the crossover and sub delay didn't have much impact (assuming you already tried changing them per Jim's suggestion?).

Thanks for the feedback. smile.gif

Below is an earlier post about my room and system. The room is a bit irregular as you can see. On the other side of the living room window there is a corner, but the wall is only 3ft wide. The distance between the corners on either side of the living room window is 11ft. Is the corner with the 3ft wide wall enough to cause the the modes your are referring to?

Here's a pic of that corner;


I haven't had the chance to try Jim's crossover suggestion yet (been sick the past few days), but I definitely plan to experiment with crossover settings to see what happens.

Here's the post;

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Thanks for the feedback. Being a complete newby to measuring I wasn't sure if it was mood or not. Here are some details about the measurement, my equipment, and my room. Btw, I haven't gotten to the part about waterfall measurements in the REW guide yet. I'll post such a graph when I get to that.

The measurement your seeing in the graph is an average of three measurements; one taken at the center prime LP at ear level, the second about 12" to the left of the first measurement position at ear level, and the third about 12" to the right of the first measurement at ear level. I applied 1/6th smoothing to the final graph per REW guide suggestion. It includes Left + Right + Sub. This evening I plan to take some measurements with the sub turned down some.

Speaking of sub level, I don't understand why the sub level is elevated. Using my Radio Shack SPL meter (C weighted, slow response per my processor's instructions) I set each speaker and the sub to 75db. So how did the sub level on the graph end up so hot?

Other than a single PEQ available for the sub on my processor (it's not being used), there is no EQ available/being used in my system. I'm considering adding some kind of PEQ unit for the sub.

My setup is 5.1 that I use for movies and music. Speaker configuration used depends on the content being played and my mood (2.1, 3.1, 4.0, or 5.1). My equipment includes;

Pre/Pro - Anthem AVM20
Amp - Parasound 5250 (5 channels)
L&R speakers - Soundfield Audio Monitor 1
Center speaker - NHT AudioCenter 2
Surround speakers - NHT SB 1
Powered Sub - SVS 16-46PC+ (located in a corner behind the front left speaker)
Sources included CD, DVD, BD, SACD, DVD-Audio, and wireless streaming from my computer via a Logitech Touch.

The room is a living room and dining room combo. Dimensions are approx 14x25 with a cathedral ceiling. The room is open to an upstairs landing and a short hall on the first floor to the den. There's also an open doorway from the dining area to the kitchen. I estimate the volume of the room including the open upstairs landing is about 5500 cubic feet. There are no room treatments, just standard furniture (treatments not likely to pass spousal approval). The floor is carpet/padding over concrete. Here's some pics that may help you visualize my space.

Panorama of listening/viewing area


View from TV looking behind listening/viewing area


View from corner where sub is located


View from end of living room



Right now I'm focusing on learning how to use REW and interpret the graphs. I'm considering upgrading my sub; perhaps with a better single sub or perhaps a pair of subs. I'd like to learn how to properly set up and EQ a sub(s) so I can get the best out of my upgrade. A smooth response throughout the room is not a priority since I'm the only one that cares about SQ and 99% of the time I'm in the prime LP (center seat on couch).

Am I on the right track?

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post #3698 of 12052 Old 06-18-2013, 09:58 AM
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Originally Posted by jkasanic View Post

especially if modifying the crossover and sub delay didn't have much impact (assuming you already tried changing them per Jim's suggestion?).
I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

Edit...as info following is before/after sub/FL/FR. Red is audyssey set sub at 13' and 80Hz x-over, Green is 100Hz x-over and sub distance at 16'.

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post #3699 of 12052 Old 06-18-2013, 10:03 AM
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Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

+1

I'd like to know this as well.

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post #3700 of 12052 Old 06-18-2013, 10:14 AM
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Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

+1
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post #3701 of 12052 Old 06-18-2013, 10:16 AM
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Originally Posted by fotto View Post

Quote:
Originally Posted by jkasanic View Post

especially if modifying the crossover and sub delay didn't have much impact (assuming you already tried changing them per Jim's suggestion?).
I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I

 

I have compiled a Guide to the Sub Distance Tweak Procedure, based on the advice of the guys who pioneered it - Mark Seaton, Craig John, giomania etc.  I have attached it.

 

 

 

 

 

Audyssey Sub Distance Tweak Procedure.pdf 1,121k .pdf file
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File Type: pdf Audyssey Sub Distance Tweak Procedure.pdf (1.09 MB, 28 views)
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post #3702 of 12052 Old 06-18-2013, 10:28 AM
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Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

Edit...as info following is before/after sub/FL/FR. Red is audyssey set sub at 13' and 80Hz x-over, Green is 100Hz x-over and sub distance at 16'.


As far as best practice, I would tune in the sub without Audyssey engaged. The more you can take advantage of the best ACOUSTIC configuration for the sub, the less Audyssey has to do when you re-engage it.

Its also possible that the best scenario maybe missed entirely if your running correction devices while your dialing in.

In the way I see things, IDEALLY, you want your room right using acoustic tools only, WITHOUT correction devices at all. Correction devices should only be employed when you have exhausted all your acoustic fixes. Dont think that Audyssey and such dont have detrimental side effects.

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post #3703 of 12052 Old 06-18-2013, 10:29 AM
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Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

Edit...as info following is before/after sub/FL/FR. Red is audyssey set sub at 13' and 80Hz x-over, Green is 100Hz x-over and sub distance at 16'.


There is no exact science to this, but you seem to be doing it the way most of us do. After Audyssey finishes, run frequency sweeps 20-300Hz using Center+Subs (or L+R+Subs), observe the smoothness in the splice region, play with different sub distance settings until the smoothest splice is achieved. You can adjust crossovers and repeat the procedure. Your after response curve looks pretty good.
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post #3704 of 12052 Old 06-18-2013, 10:42 AM
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Originally Posted by AustinJerry View Post

There is no exact science to this, but you seem to be doing it the way most of us do. After Audyssey finishes, run frequency sweeps 20-300Hz using Center+Subs (or L+R+Subs), observe the smoothness in the splice region, play with different sub distance settings until the smoothest splice is achieved. You can adjust crossovers and repeat the procedure. Your after response curve looks pretty good.

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As far as best practice, I would tune in the sub without Audyssey engaged. The more you can take advantage of the best ACOUSTIC configuration for the sub, the less Audyssey has to do when you re-engage it.

Its also possible that the best scenario maybe missed entirely if your running correction devices while your dialing in.

In the way I see things, IDEALLY, you want your room right using acoustic tools only, WITHOUT correction devices at all. Correction devices should only be employed when you have exhausted all your acoustic fixes. Dont think that Audyssey and such dont have detrimental side effects.

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Originally Posted by kbarnes701 View Post

I have compiled a Guide to the Sub Distance Tweak Procedure, based on the advice of the guys who pioneered it - Mark Seaton, Craig John, etc.  I have attached it.

Audyssey Sub Distance Tweak Procedure.pdf 1121k .pdf file

Thanks for the guide Keith and all the advice (Jerry & Jim). Will have to drop back and digest this some more. I may be getting to the point of diminishing returns. I am also focusing on building a ceiling cloud to finally address the front reflections I documented in another thread way to long ago tongue.gif I have some nice before/after ETC's I'll post when all's said and done.
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post #3705 of 12052 Old 06-18-2013, 10:43 AM
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As far as best practice, I would tune in the sub without Audyssey engaged. The more you can take advantage of the best ACOUSTIC configuration for the sub, the less Audyssey has to do when you re-engage it.

Its also possible that the best scenario maybe missed entirely if your running correction devices while your dialing in.

In the way I see things, IDEALLY, you want your room right using acoustic tools only, WITHOUT correction devices at all. Correction devices should only be employed when you have exhausted all your acoustic fixes. Dont think that Audyssey and such dont have detrimental side effects.

Hi Jim

So am I better offer setting up the sub without the AVR too? If I take my REW ouptut straight to the sub and measure that, so I'm working with the Sub alone. Good or bad idea?
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post #3706 of 12052 Old 06-18-2013, 10:57 AM
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Hi Jim

So am I better offer setting up the sub without the AVR too? If I take my REW ouptut straight to the sub and measure that, so I'm working with the Sub alone. Good or bad idea?

I would look at the test measurements both with and without the AVR, yes. But generally, I would give more weight to both given that where in the frequency range the sub and mains integrate, there is interaction. Ultimately, the way you will be listening is with both engaged, so ultimately you want the best sound with both running.

How I would go about it is getting the mains in the best spot first (looking at them only initially). Then, trying the sub in different places and finding the one that most compliments the mains.

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post #3707 of 12052 Old 06-18-2013, 12:19 PM
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Ok, I did attempt to do this for my L+R+Sub measurement:




IIUC, the peak at 30Hz would indicate this is not minimum phase behavior?  Or??
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post #3708 of 12052 Old 06-18-2013, 01:17 PM
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I have compiled a Guide to the Sub Distance Tweak Procedure, based on the advice of the guys who pioneered it - Mark Seaton, Craig John, etc.  I have attached it.




Audyssey Sub Distance Tweak Procedure.pdf 1121k .pdf file

***Ahem*** It is giomania with a small "g". smile.gif

Also, I think you spelled "centre" incorrectly. wink.gif

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post #3709 of 12052 Old 06-18-2013, 01:32 PM
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Originally Posted by fotto View Post

Quote:
Originally Posted by jkasanic View Post

especially if modifying the crossover and sub delay didn't have much impact (assuming you already tried changing them per Jim's suggestion?).
I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

Edit...as info following is before/after sub/FL/FR. Red is audyssey set sub at 13' and 80Hz x-over, Green is 100Hz x-over and sub distance at 16'.

 

Quote:
Originally Posted by Saturn94 View Post

Quote:
Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

+1

I'd like to know this as well.

 

Quote:
Originally Posted by mark_anderson_u View Post

Quote:
Originally Posted by fotto View Post

I have been doing a lot of measuring/tweaking over the last 1-2 weeks to improve response at my sub/front splice using both x-over and sub distance setting options. Is there a "best practice" out there for doing this testing? I have been testing by taking sweeps of various x-over settings, then taking the best x-over setting from those sweeps and then doing sweeps with varying sub distance settings (using the optimal x-over I found) for further fine tuning. Seemed to me that would be most logical flow but curious as to what others are doing.

+1

 

Looks like you guys have already gotten some excellent advice from Keith, Jerry and Jim.  My experimentation with the sub distance tweak is well-chronicled in this thread starting here.  Long story short, make sure you consider the effects the tweak has on all 3 mains plus sub as well as your L+R combined response plus sub.

 

I think a good starting point for the xover setting is to plot your mains and your sub response separately on the same chart like this:

 

 

Take a look at the xover region (typically 70-110Hz).  With the null in my right speaker hitting just below 90Hz, I decided I should probably keep my xover at this point or higher (my prepro recommended 90Hz for L & R and 80Hz for C).  Since my sub output starts to rolloff above 90Hz, I'm currently crossing all of my mains at 90Hz.

 

After considering the response of each speaker and picking the crossover, you can then start experimenting with the sub distance tweak.  Finally, if you have any EQ, you can apply and confirm results.

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post #3710 of 12052 Old 06-18-2013, 02:18 PM
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Quote:
Originally Posted by giomania View Post

Quote:
Originally Posted by kbarnes701 View Post

I have compiled a Guide to the Sub Distance Tweak Procedure, based on the advice of the guys who pioneered it - Mark Seaton, Craig John, etc.  I have attached it.




Audyssey Sub Distance Tweak Procedure.pdf 1121k .pdf file

***Ahem*** It is giomania with a small "g". smile.gif

Also, I think you spelled "centre" incorrectly. wink.gif

Mark

 

smile.gif My sincere apologies, Mark. My post has been edited for posterity.

 

I did?  Darn spell checkers.... :)

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post #3711 of 12052 Old 06-19-2013, 08:45 AM
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I would like to learn to use REW to optimize my speaker/sub placement and to incrementally and optimally treat my new theater build! biggrin.gif

I am ready to purchase a USB microphone and I am trying to decide between the UMIK-1 and the UMM-6! confused.gif

On the Cross Spectrum site it looks like the UMIK-1 is now available individually calibrated for 0, 45 and 90 degree angle of incidence like the UMM-6 microphone. From what I have read the UMIK-1 is more or less plug and play as opposed to the UMM-6 which has to be calibrated with an SPL meter is that correct?

Has the UMM-6 been added or is close to being added to the REW drop down menu yet by REW author John M?

My real question is which mic should I purchase? Any compelling reasons at this time to go for the UMM-6 over the UMIK-1 in regards to accuracy, build quality, setup or anything else? confused.gif


Thanks!


...Glenn smile.gif
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post #3712 of 12052 Old 06-19-2013, 09:00 AM
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Originally Posted by Glenn Baumann View Post

I would like to learn to use REW to optimize my speaker/sub placement and to incrementally and optimally treat my new theater build! biggrin.gif

I am ready to purchase a USB microphone and I am trying to decide between the UMIK-1 and the UMM-6! confused.gif

On the Cross Spectrum site it looks like the UMIK-1 is now available individually calibrated for 0, 45 and 90 degree angle of incidence like the UMM-6 microphone. From what I have read the UMIK-1 is more or less plug and play as opposed to the UMM-6 which has to be calibrated with an SPL meter is that correct?

Has the UMM-6 been added or is close to being added to the REW drop down menu yet by REW author John M?

My real question is which mic should I purchase? Any compelling reasons at this time to go for the UMM-6 over the UMIK-1 in regards to accuracy, build quality, setup or anything else? confused.gif


Thanks!


...Glenn smile.gif

I have UMM-6. Wish I'd bought UMIK-1. From what I understand it has lower noise floor and calibration includes sensitivity (SPL). Also, as you said is supported in REW.

I think when I ordered it was out of stock at CSL and I read something about some issues with the current batch (about 6 weeks ago). Don't recall what they were. but I'm sure you'll find on forum. This was the main reason that steered me to the UMM-6

Regards

Mark
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post #3713 of 12052 Old 06-19-2013, 09:22 AM
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Originally Posted by mark_anderson_u View Post

I have UMM-6. Wish I'd bought UMIK-1. From what I understand it has lower noise floor and calibration includes sensitivity (SPL). Also, as you said is supported in REW.

I think when I ordered it was out of stock at CSL and I read something about some issues with the current batch (about 6 weeks ago). Don't recall what they were. but I'm sure you'll find on forum. This was the main reason that steered me to the UMM-6

Regards

Mark

You mean some sort of issue with a batch of the UMIK-1 mics? confused.gif


...Glenn smile.gif
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post #3714 of 12052 Old 06-19-2013, 10:11 AM
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You mean some sort of issue with a batch of the UMIK-1 mics? confused.gif


...Glenn smile.gif

Yes, but no idea what it was
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post #3715 of 12052 Old 06-19-2013, 10:19 AM
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thank you for the thread.

how can the time reference loopback connection be made when a USB microphone is used?

also, is the initial sound card calibration still needed/valid given that the input signal does not go through the soundcard analog stage ?

Did you ever figure this out and how are you doing the soundcard cal. I'm stuck
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post #3716 of 12052 Old 06-19-2013, 10:42 AM
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You mean some sort of issue with a batch of the UMIK-1 mics? confused.gif


...Glenn smile.gif

There's a good discussion on the Mics here: http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs#post_22790113
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post #3717 of 12052 Old 06-19-2013, 11:18 AM
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Did you ever figure this out and how are you doing the soundcard cal. I'm stuck

When using the USB mic and HDMI, no soundcard calibration is required. If you are using a different configuration, recall that this is the USB mic/HDMI thread. You are more likely to receive useful advice on the Home Theater Shack forum
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post #3718 of 12052 Old 06-19-2013, 11:35 AM
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Quote:
Originally Posted by AustinJerry View Post

Quote:
Originally Posted by mark_anderson_u View Post

Did you ever figure this out and how are you doing the soundcard cal. I'm stuck

When using the USB mic and HDMI, no soundcard calibration is required. If you are using a different configuration, recall that this is the USB mic/HDMI thread. You are more likely to receive useful advice on the Home Theater Shack forum

 

@Jerry:  I believe the first part of this was in relation to the time loopback reference which was discussed recently and the consensus seems to be is not possible with a USB mic (independent of HDMI or legacy cable connection).

 

@MAU:  There was also reference to the SPL calibration that is still required with the UMM-6 (vs. UMIK-1) which we've also discussed in this thread ad nauseam.  Suffice it to say that most users in this thread would not choose one mic over the other based solely on this condition (which could change in the future based on John M's ability to incorporate it).

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post #3719 of 12052 Old 06-19-2013, 02:57 PM
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@Jerry:  I believe the first part of this was in relation to the time loopback reference which was discussed recently and the consensus seems to be is not possible with a USB mic (independent of HDMI or legacy cable connection).

Showing my ignorance here. What is "time loopback reference" and what is it used for and do I really need it?
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post #3720 of 12052 Old 06-19-2013, 03:19 PM
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Showing my ignorance here. What is "time loopback reference" and what is it used for and do I really need it?

When using an external soundcard with a "legacy" REW kit, there are two audio channels. One of the channels is used to output the REW test signal. The unused audio channel can be looped back, I.e. the output can be connected back to the input for the same channel. This loop back provides REW with a timing reference that allows it to compensate for any internal delays caused by the measurement electronics. This is about the extent of my knowledge, and it wouldn't surprise me if I have explained it wrong. However, one of our expert contributors reminds us periodically that use of a loop back improves the accuracy of distance measurements when running impulse response measurements.

However, when using a USB mic (and no external sound card), a loop back connection is not possible. Several other of the expert contributors have said that the usefulness of the impulse response measurements are not affected significantly. So, the take-away is that we don't need to worry about it.
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