Manual Inputs Using REW

Hello All,
I am just getting started with REW. I do not currently have a laptop and I am not quite ready to move my pc into my HT room.

Could any one help with making basic SPL readings and manually entering in to REW to get a room analysis? I hesitate to ask but I have not found info in these forums here.

I have a Pioneer VSX-92TXH and a HSU BAS test disc if this helps.

Thanks for your input.

Go to the downloads page and get the Excel .xls file that corresponds to your Radio Shack meter type. The calibration for your meter is built in.

Then download the 1/6th octave sinewaves and make a CD.

That's about all you need.

brucek

OK Thanks,

I have done that now and to get the readings I need to do the following correct?

1. Establish the 75dBL reference level by playing the CD or using the tones if available in my AVR?

2. Play the CD and mark down the level from the SPL Meter

3. Enter into the Excel sheet.

Should I disconnect my front mains?

Do I want to run my AVR in signal direct mode with no processing?

Yeah, it's best to disconnect the mains and do a sub only measure. This way you have no other influences. Simply remove the speaker wires for the mains (with power off).

Normally you set the receiver in the standard digital stereo mode with the subwoofer crossover set as you would normally (i.e. 80Hz).

Also note that you may have some peaks and so if you set the 75dB at some huge peak, the graph will show a bit low. So play the CD up through the 1/6th octave tones first and get a feel for it. Then maybe pick an appropriate frequency (50Hz) that doesn't seem ridiculously louder than the rest and set your 75dB level on the receiver volume at the listening position, and then you're ready to go......

brucek

Thank you for your help Bruce,

I currently run my X-Over at 50 so I did a graph with this X-Over and another at the 80Hz X-Over.
My mains go down to 30-35hz so I set my crossover about double this at 50hz.

This 1st JPG graph is with the 50hz X- Over
The 2nd JPG graph is with the 80Hz X-Over

Do you have any thoughts on what you are seeing with these?
I start out well out of the gate with good readings at the first octaves but at the 22 there is a significant drop. Will the equalizer in my Pioneer VSX-92 be able to lift up this drop?

I am going to purchase the USB Sound Card so I can go deeper into this but I thought this would be a great place to start to learn about calibrations.

Thanks for your help and thoughts.

Attachments

	50 Hz X-Over.JPG (72.8 KB, 37 views)
	80Hz X-Over.JPG (71.5 KB, 37 views)

I have a couple observations.

I guess you can see what I was talking about with respect to the level you set the receiver to take the test. It's a bit high.

I'm surprised about the low end extension you're showing. You seriously had that type of output down to 7Hz?

You do indeed have a null at 22Hz and a peak at about 25Hz. This is where REW would offer more accuracy. I doubt the equalizer can do much to a true null, but it can bring down a peak easily.

Big recommendation...... use REW - so much easier..

brucek

I thought the out put was close to 80. Hmmm

The HSU VTF-MK3 is known for great low end extension. These are the readings read on the SL Meter. I thought it was odd also that I would immediately begin to show high readings. From all my reading on the forums I usually see the first octaves show very low on the graphs.

What X-Over do you recommend after looking at these graphs?

Are these readings close to what you would like to see in a perfect world?

I am one step away from being REW ready - I was at Micro center today and the only external USB they had was the Sound Blaster for 50.00 From what I have read some people are having success using this one with Vista. I would like the Turtle Beach brand but I am trying to find it for a good price.

Thanks

It's impossible to recommend a crossover until you see the mains only graph.

I can't resolve how your sub has continuous rising output level down to 7Hz. The specification on the HSU VTF-MK3 using the max extension mode is 18Hz +/-2 dB. I'd like to see an REW response plot. Are you using a Radio Shack meter with the C-mode switch position? (and using the correct excel plot?

brucek

I can't resolve how your sub has continuous rising output level down to 7Hz. The specification on the HSU VTF-MK3 using the max extension mode is 18Hz +/-2 dB. I'd like to see an REW response plot. Are you using a Radio Shack meter with the C-mode switch position? (and using the correct excel plot?

Yes, C weighting - Slow Response at the 80

I entered in the readings after subtracting from 80 starting from the first sounds.

Can you explain what this means?

On the SPL Meter if the reading was + 0 I added it to 80, if the reading was minus from 0 I subtracted. Then I entered in the spreadsheet and as was mentioned earlier, the spreadsheet will adjust for the SPL Calibration.

Correct?

Thanks again

Yep, that's correct...

I'm also learning ... I got the SoundBlaster Live 24 Bit and I remember that "Vista Compatible" was printed in the package

I used REW last week, and like you, I started with manual readings and a graph ... but REW makes everything easy; if you want to use your AVR EQ ... with REW it will take you no time; what I did was to run the autocalibration, then used REW to see the graph; after looking at the graph I looked for peaks and deeps; then went to my AVR EQ and started changing the gain to one frequency at the time ... everytime I made a change a measured with REW to see my new graph; if I didn't like the result I set it back where it was before... it will take time, but it will be worth it

Looking at your graph, it seems to me that maybe you inverted the inputs ... for example, in the 7Hz, instead of +23 it should be -23 ... this will make sense, because the lower the frequency your response has to be lower not higher ... this will mean that your sub will have a response of 57 at 7Hz and around 88 at 45Hz

Salvasol,
Have you had success with the Soundblaster card working with VISTA? If so I may try this external card because it is available at a retailer near me. I can not seem easily locate the Turtle Beach Audion Advantage card. Online most are sold out.

Ok, So are you running REW after each adjustment to your AVR equalizer?

Will REW show you the AVR graph? I may have missed something on how you hook up everything.

This info is all new to me and the learning curve has been steep. I appreciate all the input.

I simply bought mine from the company itself. I just clicked their BUY button and had it in a few days. I found most places seemed to be out of stock as you say....

Can you explain what you mean by these statements?

Have you seen this sticky thread on how to hook things up?

brucek

what I mean is - After each eq adjustment do I run REW again to see the change?

I have the wiring diagram printed for reference.

My PC appears to have a line in, line out and mic input. Can I use this onboard integrated sound card?

The pc sound card information appears to show up on the settings page of REW.
Will this work?

Yep............

Yep.........

brucek

My laptop has XP ... I'm not sure if it will work with vista, but the package said "Vista compatible".
In the other hand, I saw the response from Brucek that you can use the card you already have in your computer as long it has a line in and line out according to the instructions you'll be fine

This is correct, let's say that I change the setting on the 49Hz frequency, I wrote down where the gain was (ie. +2.5db); then I changed to +3.5db ... I run REW and see my new graph, if it looks better than before and this change did was I expected, I leave it that way ... if not I changed back to where it was ... ...

Yes, REW will show you a graph anytime you run a test; the hook up is the same you don't need to do anything else ...

I feel your pain, same thing happened to me ... and I'm still learning to use REW and interpret the graphs and most important understand what to change to improve response ... ...