BFD and REW question about hook up and calibration

[apilon]

Good day all ,

i am new to this forum and learned a lot by reading others people post. I am sorry if my questions sounds like deja view....

first question is. I have a Harman Kardon AVR 635 and i am about to do calibration tonight. I will use the HARMAN KARDON EZ EQ to do the primary audio calibration then use REW and BFD to do any correction not made by the EZ EQ. I was going thru the REW help file and looking at the diagram to connect the SPL and sound card to the AVR aux in ......i noticed that i will need to buy 2 rca to stereo 1/8 adapter.... checking my computer sound card i saw that it has both a Digital in and digital out connector. Could i use these 2 connectors and therefore only using 2 RCA cable which would eliminate the need for the 2 adapter??

second question:

i read on the forum that the reason for hooking up to the aux in is to first calibrate the subwoofer then calibrate the mains with the sub to assure proper integration. My question is once i have calibrated the sub wouldn't i screw up the sub calibration settings if i make correction for the mains/sub integration ??


Alain

[brucek]

Could i use these 2 connectors and therefore only using 2 RCA cable which would eliminate the need for the 2 adapter??

No, REW is setup to use analog only.

My question is once i have calibrated the sub wouldn't i screw up the sub calibration settings if i make correction for the mains/sub integration ??

No. Once the sub is equalized by itself, the mains are added to check for interaction around the crossover frequency. A small amount of phase adjustment and sometimes a small tweak of the filters is required to ensure a smooth transition.

brucek

[apilon]

brucek wrote:

No, REW is setup to use analog only.



No. Once the sub is equalized by itself, the mains are added to check for interaction around the crossover frequency. A small amount of phase adjustment and sometimes a small tweak of the filters is required to ensure a smooth transition.

brucek

Thanks a lot Bruce ,

I did not see it in the guide unless i just was not paying attention but i would guess that the spl need to be set up at seating location and ear level ?

Alain

[brucek]

I did not see it in the guide unless i just was not paying attention but i would guess that the spl need to be set up at seating location and ear level ?

Yes. Some people also take other readings in various seating positions if they have a theater, to see if they need to average out their response with their BFD filters.

brucek

[Malice]

brucek wrote:

No, REW is setup to use analog only.



No. Once the sub is equalized by itself, the mains are added to check for interaction around the crossover frequency. A small amount of phase adjustment and sometimes a small tweak of the filters is required to ensure a smooth transition.

brucek

Ken, as the REW is analogue only and only one line out on the soundcard , I have to split the PC line-out to feed the external 5.1 analogue inputs on my amp to be able to sweep both the fronts and sub simultaneoulsy for interaction between the two. But here's the rub, when the amp is switched to EXT-IN to reproduce the analogue sound sweep signal, all digital processing is bypassed, including the crossover.

So my question is, how can one really test for front + sub interaction for use with a crossover but for which it is not possible to test? Or am I losing the plot here and have missed the blindingly obvious solution?

Cheers

Bob

[surrey lad]

Malice wrote:

So my question is, how can one really test for front + sub interaction for use with a crossover but for which it is not possible to test? Or am I losing the plot here and have missed the blindingly obvious solution?

Cheers

Bob

Not sure if i'm qualified yet to start giving out advise as I haven't yet managed to setup REW, but here goes!!

I also split the PC line-out, but as my EAD processor lacks 5.1 pass-through I connect to it using one of the standard stereo analogue inputs and set my fronts to small (80Hz cutoff) and leave it set as stereo

[Malice]

surrey lad wrote:

Not sure if I'm qualified yet to start giving out advise as I haven't yet managed to setup REW, but here goes!!

I also split the PC line-out, but as my EAD processor lacks 5.1 pass-through I connect to it using one of the standard stereo analogue inputs and set my fronts to small (80Hz cutoff) and leave it set as stereo

Good point. So thinking about this "solution" a bit more, it would probably make sense to connect to a "normal" stereo input for all the testing of all the channels and just disconnect those speakers which are to be excluded from the measurement. In this way the response of the speakers (sub as well) would be measured by using the crossover filters on the amp. When measuring the response of the entire system, I could just switch the amp to 5/7 channel stereo to play the sweep through all the speakers.

On balance probably a smarter way to set up your system rather than use the EXT-IN 5.1 analogue connections which as you say are pass-through on my amp.

[brucek]

So thinking about this "solution" a bit more, it would probably make sense to connect to a "normal" stereo input for all the testing of all the channels and just disconnect those speakers which are to be excluded from the measurement

Yep, as surrey lad says, simply feed your receiver/processor with a Y-splitter into the AUX or CD analog input and you have all your speakers and crossovers available.

Some people simply disconnect the speaker wire from the speakers they don't want turned on (carefully of course), or for those with separate amplifiers, just turn off the ones you don't want on...

brucek

[Malice]

Of course you know what this now means? A clean sheet and a new start on re-calibration!