Anthem D2/D2v/AVM50/AVM50v/ARC1 tweaking guide - Page 1083

When we measure using arc, there are two options for subs.
One is in arc, where we have the option of one or two subs. We always chose one.
There is also an option in the d2 for one or two subs. Do we use one only when measuring? Then, post measurement, do we chose two subs?
Or, regardless of the number of subs we have, is the magic number always one?
Thx
Walt

I believe it stays at one.
John

How do we handle two subs using this procedure? One on, and one off?
And, if the subs are at very different distances from the listening position, should not the distance for each be handled individually, per test?
i.e. If the left sub is 16' from prime, set this distance in D2, and test per outline. Then, for the sub on the right, which is 20' from prime, set that distance in the D2, and proceed as per outline.(after turning off the left side sub)
walt

You set the volume on each sub individually, 72dbs each should achieve 75dbs total, as for the distance you take the average of the two subs distances and enter that, so using your example (20' plus 16' = 18').

John

I believe you set up each sub individually, setting each to 75dB and then averaging the distances. Phase and polarity are also done separately. ARC hears them as one.
John

I agree with both Johns.

Also, when you run ARC, make sure both subs are on so that ARC can hear both of them at the same time. You will have to adjust the phase and polarity of your subs because ARC will not do that, and you should do that before you run ARC.

Actually, each sub should be set to 72db. The two of them together would then yield 75db.

Yes I now remember, thanks.
John

This would be a good time for me to remind Anthem that the next processor needs more then one sub channel. I consider it my duty to bring it up every few months.

john and john et.al:
i'd like to be certain that i posed my second question in the correct frame.
i.e. i was referencing the NULL method of setting sub levels, so as to agree with the LF.
Were your answers specific to that question?(if not, my bad)
It seems to me that when setting volume levels, distance matters.(it really does - there is a rapid drop off in dB's from near field to 18' away,= prime seating)
So - after reversing the LF leads, i should consider the two subs as one, having first set each one to 72dB?
thx
walt

My Anthem uses 6 Sub Channels

My answer was not in reference to using the Null method, so please strike it from the record.

I also wasn't referring to those techniques as I am unfamiliar with them, sorry.
John

This was an AHA moment for me.
sorry for the initial confusion regarding my intent.
however, the question remains: using the null method for ensuring that the subs agree with the mains, do i treat each sub individually for null purposes, then have arc treat them as a pair for the measurement process?
Eh?
walt

You mean your Anthem provides one channel to six subs. I've scaled back from six to four. So far I've resisted any external sub DSP box (Audyssey, PBK, Velodyne SMS, ect) but life would be a lot more manageable if the Anthem had two or three more sub channels. Actually while they are at it I'll just take a 7.7 or 9.9 processor.

walt- For the null method yes do each individually. For ARC think of it as one subwoofer since the Anthem/ARC only has one sub channel.

ETA:This goes out the window if you are using the distance setting for phase control. Set the distance to an average of your subwoofers and adjust phase on the individual subwoofer amps.

ETA2: The distance setting has nothing to do with the level setting. At least in practice.

No, you should have the both playing at the same time that you are adjusting the distance. Since you are using the null method, the distance with the lowest number is the one that you want to use. After you determine the distance, be sure to switch the cables on the back of your speakers back to black on black and red on red. Make sure you balance your subs before you set the phase.

Yes - 6 Individually controlled Subs.

I'd suggest that this would work optimally only if he has already put both subwoofers in phase with each other and you can't do that with the distance setting.

again, thanks to all who responded.
walt

Dr - You probably have answered this somewhere earlier in the thread but what if anything do you use between your sub amps and the Anthem?

I was WAITING for that question.

Rane - SM-26 - you can buy them on eBay Cheap.
I own 4 of them for many uses. I have never paid
more than $50 for any of them.

Yes, I agree. The subs will have to be in phase with each other first. Then, he will have to play a tone around his crossover. Then as the distance is being adjusted the one that gives the lowest SPL is the one that should be used.

Ah I thought for sure you would have one of those fancy Rane active crossover/limiter/compressor/graphic/parametric/EQ/Splitter/Mixer/Bottle Opener models. I may have to pick up an SM 26 especially since most of my sub amps are behind my screen now. Too bad the SM 26 doesn't have a polarity switch on the outputs it would be perfect for my use then, although a bottle opener option would come in handy too.

Walt:

1. I assume the subs are in their optimal positions as well. With subs on opposite sides of the room, set the phase knob of one to 0 and the other to 180 or whatever angle gives you the best frequency response using "Quick Measure". Afterwards, then for each individual sub, set level to 72-73dB if you have 2 subs for a combined 75dB or so. The math isn't precise in the real world so 2 subs set at 72dB will not necessarily produce s combined 75dB, but its close enough anyways

2. Reverse the polarity of the LF speaker. All other speakers MUST be disconnected. You need to listen only to the 2-subs and LF speaker only.

3. Have a variable (external) frequency source that you'll use to vary the frequency over several values around the xover ferquency. If its 80Hz, then i'd take measurements every 5 Hz starting from 60Hz and up to 100Hz.

4. For each test frequency and (with RS meter in hand), vary the sub distance setting until you read a minimum SPL value on the RS meter. Make sure its the minimum by varying the distance around it in 0.5ft increments. You should be able to notice a rise in SPL reading as you go beyond or before the minimal point.

If, for example, the distance to get a maximum null is 8 feet, you'll also get another null at 16 ft, 24ft etc. Thus value is a function of your room dimensions. Please note these values down as you go!

5. Repeat steps 3 & 4 for the next frequency.

You can tabulate the data as i have in my simple attachment. Note that the term "1st NULL" refers to the initial distances i got the null. The term "2nd NULL". To decide which NULL column to use, I choose the one where the dataset had the least variance for all frequencies used in this test. Once i decided on the colum of data to use (2nd NULL in my case), i then computed the average distance from that column and then used that as the new distance value in the "Subwoofer Distance" setting menu.

In my case, it was 31 ft, yet the actual physical distance from my sub to my listening position is 12 feet. The two do NOT have to match. Th is OK. Folks who use Audessey are familiar with this as well.

6. Reverse the LF speaker polarity to normal (!!!) and re-connect the rest of your speakers to the amplifier.

7. Enjoy some deep bass LFE music/movies. This procedure is well worth the effort in all cases, imho. The bass sounds amazing and the subs seamlessly integrate well with the mains

 

Speaker Phase Calculations.zip 8.056640625k . file

You Mean you can not get the wires in the right order???????????

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Bob,

I just finished watching "The Green Berets". It's mastered in Dolby TrueHD 1.0. The Oppo 83 displayed this.

Was therefore surprised to see my D2v indicating 5.1 Dolby TrueHD 48kHz input when Select is pressed. However, only the Center has any output. Signal is clear and uncorrupted.

Ben

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John

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