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Podcast HomeTheaterUnited Podcast Episode 15 - Dave Upton on room correction and calibration with REW and Audyssey (1 Viewer)

JohnRice

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I have only 2 problems with mine.
  • Size - It's huge, which severely limits placement options in my room. I want to go dual at some point and cannot see that ever happening with this one.
  • No PEQ - Until I get my hands on a Processor like the AVM 70, I have very little control [or even knowledge] of it's peaks and nulls.
That said, this sub has been anchoring my HT for nearly 14 years and has never disappointed in a general sense.
Yeah, the AVM-70 will give you more options, or better yet, outboard correction like Dave Upton uses.

Whatever I replace it with won't be any smaller. I've pretty much decided on a sealed dual 15" model. It just comes down to which one(s) to get.
 

John Dirk

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Whatever I replace it with won't be any smaller. I've pretty much decided on a sealed dual 15" model. It just comes down to which one(s) to get.
Unfortunately in my case, space is a limiting factor. I'll probably end up with dual 10's. The RSL "Speedwoofers" look interesting. I may end up auditioning a pair one day.
 

JohnRice

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Unfortunately in my case, space is a limiting factor. I'll probably end up with dual 10's. The RSL "Speedwoofers" look interesting. I may end up auditioning a pair one day.
I wouldn't think those would hold up to the SVS you have.
 

John Dirk

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I wouldn't think those would hold up to the SVS you have.
Glad you brought that up. Whenever I run Audyssey it immediately identifies my sub as "too loud" and initiates a level-matching process. By the time I get it down to where Audyssey will continue it's usually around 30% tops, making me wonder if the PB12 Plus/2 is not just total overkill for my room. Of course I could just bypass level matching but what I actually do in practice is follow its recommendations and then just gradually increase the sub output to my liking after Audyssey has completed.

I've also taken a preliminary look at this model from HSU. It's probably on backorder for the next several months but I'm thinking the Anthem AVM70 will likely be my next purchase anyway, so I have plenty of time to sort it all out.
 

Dave Upton

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Glad you brought that up. Whenever I run Audyssey it immediately identifies my sub as "too loud" and initiates a level-matching process. By the time I get it down to where Audyssey will continue it's usually around 30% tops, making me wonder if the PB12 Plus/2 is not just total overkill for my room. Of course I could just bypass level matching but what I actually do in practice is follow its recommendations and then just gradually increase the sub output to my liking after Audyssey has completed.

I've also taken a preliminary look at this model from HSU. It's probably on backorder for the next several months but I'm thinking the Anthem AVM70 will likely be my next purchase anyway, so I have plenty of time to sort it all out.
Audyssey is really, really stupid. What is is looking at is likely a massive peak due to room gain. There are two ways to work around this.

1) What I will typically do to defeat Audyssey's stupidity is pre-EQ the sub using a miniDSP device - which can be had cheaply. This takes about 15 minutes using REW and a UMIK. Here's a great guide you can follow:
2) If DSP is too much effort, here's the trick. This is something I typically do with a piece of painters tape and a marker or pencil. Put the tape on the amp plate so you can mark next to the gain knob. Note how much you have to twist the gain knob for 3dB. Now run Audyssey, and adjust your sub gain down until Audyssey doesn't throw an error on the initial level check. Be sure to check the level it's putting out with an actual SPL meter - it will typically be 65-68 dB. Then, between level checking in Audyssey and starting the measurement process, turn it up by 3dB on the gain knob.

This will raise the measurement levels enough to make Audyssey more accurate, but not enough to cause any issues. Then, once calibration is done, you can level adjust the sub to match the mains at 75dB. This usually yields a far better calibration than Audyssey will alone.
 

JohnRice

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Audyssey is really, really stupid. What is is looking at is likely a massive peak due to room gain. There are two ways to work around this.

1) What I will typically do to defeat Audyssey's stupidity is pre-EQ the sub using a miniDSP device - which can be had cheaply. This takes about 15 minutes using REW and a UMIK. Here's a great guide you can follow:
2) If DSP is too much effort, here's the trick. This is something I typically do with a piece of painters tape and a marker or pencil. Put the tape on the amp plate so you can mark next to the gain knob. Note how much you have to twist the gain knob for 3dB. Now run Audyssey, and adjust your sub gain down until Audyssey doesn't throw an error on the initial level check. Be sure to check the level it's putting out with an actual SPL meter - it will typically be 65-68 dB. Then, between level checking in Audyssey and starting the measurement process, turn it up by 3dB on the gain knob.

This will raise the measurement levels enough to make Audyssey more accurate, but not enough to cause any issues. Then, once calibration is done, you can level adjust the sub to match the mains at 75dB. This usually yields a far better calibration than Audyssey will alone.
I really want to try out the sub pre-EQ thing. Particularly because when playing music on my system, there is no correction possible other than an outboard approach like this.
 

JohnRice

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@Dave Upton , what do you think of a couple single driver 15" sealed subs for John's room? They can be quite compact.
 

Dave Upton

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@Dave Upton , what do you think of a couple single driver 15" sealed subs for John's room? They can be quite compact.
I prefer sealed subs personally, and think it would be a great option. Once you go to dual subs or more, output is never the issue - but the advantage in terms of EQ is massive. Even a pair of SB-2000's would be excellent options.

I do prefer 15's over 12's because they extend deeper and you can get usable response to 12Hz or so - which is more tactile for movies.

The cheapest option is to buy a couple of these: https://www.monoprice.com/product?p_id=41499 - you'll probably be able to get pretty great results despite the price.
 

John Dirk

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I prefer sealed subs personally, and think it would be a great option. Once you go to dual subs or more, output is never the issue - but the advantage in terms of EQ is massive. Even a pair of SB-2000's would be excellent options.

I do prefer 15's over 12's because they extend deeper and you can get usable response to 12Hz or so - which is more tactile for movies.

The cheapest option is to buy a couple of these: https://www.monoprice.com/product?p_id=41499 - you'll probably be able to get pretty great results despite the price.
Thanks for the sealed suggestion. I hadn't even thought about that. Still, as previously stated, my next upgrade will be centered on freeing me from Auddysey. After watching demos of both ARC Genesis and Dirac Live, I am just amazed at the void Auddysey represents. I can't believe Marantz is sticking with them in their processors and AVR's.

Based on what I've seen, the AVM70 [ARC Genesis] will handle the sub correctly outright. Am I correct?
 

JohnRice

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Based on what I've seen, the AVM70 [ARC Genesis] will handle the sub correctly outright. Am I correct?
Dave has ARC Genesis, but still uses outboard sub EQ. My main thing with sealed subs is they never "lose it" and get sloppy. As great as the rather old PB12/Plus-2 is, it can can lose it when really pushed.
 

John Dirk

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Dave has ARC Genesis, but still uses outboard sub EQ. My main thing with sealed subs is they never "lose it" and get sloppy. As great as the rather old PB12/Plus-2 is, it can can lose it when really pushed.

I don't know if Dave has the latest version of ARC Genesis yet with the AVM60. Based on the demo I saw, it allows for incredible control over the target curves for all speakers, including the sub. It will take me some time to feel competent enough to handle phase and time alignment manually when I finally do get dual subs.
 

3dbinCanada

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Glad you brought that up. Whenever I run Audyssey it immediately identifies my sub as "too loud" and initiates a level-matching process. By the time I get it down to where Audyssey will continue it's usually around 30% tops, making me wonder if the PB12 Plus/2 is not just total overkill for my room. Of course I could just bypass level matching but what I actually do in practice is follow its recommendations and then just gradually increase the sub output to my liking after Audyssey has completed.

I've also taken a preliminary look at this model from HSU. It's probably on backorder for the next several months but I'm thinking the Anthem AVM70 will likely be my next purchase anyway, so I have plenty of time to sort it all out.

Hi John,

If you have REW and a measurement mic like the UMIK1, you can take measurements to see wwhere your sub gives you the flattest response across the listener area. I dont know what your room looks like but I have a couch pulled 3" from the back wall on mine (the only seating area in the room) and I moved by sub around the room to see which spot gave me the most even response across the couch. I chose this position because it gave me the most even response. The different colors represent the 3 different spots on the couch. sub_at_new_location.jpg

The sub at my old location..

sub_at_old_location.jpg


and a couple of other spots


sub_at_bike_location.jpg
sub_at_left_of_sofa.jpg
 

Dave Upton

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I don't know if Dave has the latest version of ARC Genesis yet with the AVM60. Based on the demo I saw, it allows for incredible control over the target curves for all speakers, including the sub. It will take me some time to feel competent enough to handle phase and time alignment manually when I finally do get dual subs.
The AVM60 does have the latest version of ARC Genesis, but doesn't support EQ'ing/time aligning subs independent of one another. That's what I did with the MiniDSP, which presents a single "logical" time-aligned and pre-EQ'ed subwoofer to the AVM60.
 

John Dirk

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Hi John,

If you have REW and a measurement mic like the UMIK1, you can take measurements to see wwhere your sub gives you the flattest response across the listener area. I dont know what your room looks like but I have a couch pulled 3" from the back wall on mine (the only seating area in the room) and I moved by sub around the room to see which spot gave me the most even response across the couch. I chose this position because it gave me the most even response. The different colors represent the 3 different spots on the couch. View attachment 89449

The sub at my old location..

View attachment 89450


and a couple of other spots


View attachment 89451
View attachment 89452
Thanks for sharing this! I have REW but don't yet have a suitable mic. My problem is I have a pretty large sub, which gives me only about three realistic choices for location. I tried them all some time ago and my ears didn't note any pronounced differences but I realize that means nothing.

I'm thinking of making some major modifications to my room to allow for dual subs at some point but it would involve moving most of my gear to an adjacent room and rack-mounting it, so that's a big project. I'll have to weigh the pros and cons carefully before committing. Meanwhile I'm almost certain I'll be purchasing the Anthem AVM70 [or possibly a used 60] at some point so that should help.
 

Dave Upton

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Thanks for sharing this! I have REW but don't yet have a suitable mic. My problem is I have a pretty large sub, which gives me only about three realistic choices for location. I tried them all some time ago and my ears didn't note any pronounced differences but I realize that means nothing.

I'm thinking of making some major modifications to my room to allow for dual subs at some point but it would involve moving most of my gear to an adjacent room and rack-mounting it, so that's a big project. I'll have to weigh the pros and cons carefully before committing. Meanwhile I'm almost certain I'll be purchasing the Anthem AVM70 [or possibly a used 60] at some point so that should help.
This is your best bet: https://www.minidsp.com/products/acoustic-measurement/umik-1
 

3dbinCanada

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Thanks for sharing this! I have REW but don't yet have a suitable mic. My problem is I have a pretty large sub, which gives me only about three realistic choices for location. I tried them all some time ago and my ears didn't note any pronounced differences but I realize that means nothing.

I'm thinking of making some major modifications to my room to allow for dual subs at some point but it would involve moving most of my gear to an adjacent room and rack-mounting it, so that's a big project. I'll have to weigh the pros and cons carefully before committing. Meanwhile I'm almost certain I'll be purchasing the Anthem AVM70 [or possibly a used 60] at some point so that should help.
The UMIK-1 is dirt cheap in the US compared to what we Canadians have to pay. You are also correct that your ears and a bass crawl is not all that useful like my graphs show.
 

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Join hosts @Brian Dobbs and @Sam Posten as they welcome HTF co-owner @Dave Upton to discuss how to correct and calibrate home theaters using tools such as Room EQ Wizard (REW) and Audyssey, plus tips for physically modifying room layout and using wall treatments.
  • Dave’s history with HTF again and dealing with recent snow in Texas
  • What is Room Correction technology?
  • Isn’t Audyssey all you need?
  • What can consumers who have receivers without Audyssey do?
  • Why Room EQ Wizard?
  • Do you have to be an engineer type to use REW?
  • What can REW do that Audessey can’t?
  • What modifications can one do to a room to ‘fix’ what REW shows?
  • What else would Dave suggest folks look into to make their rooms sound better?

Also, Good, Bad and Ugly media reviews including Dave's latest pick!

 

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