# Integrating Creative SB X-Fi Pro with REW 5.0



## BraveHeart123 (Oct 18, 2010)

Hi Everyone.....I am completely new to calibrating sub with REW; but I've had 2 years experience with manual and PAINFUL calibration using RS Analog SPL meter and test tones. Thanx to all on this great forum; I decided to go the REW way. I've been reading a lot and used REW 5.0 for the very first time last night and I was able to generate calibration file for the X-Fi pro soundcard through loop back connection. 

Anyone pls have a look at the attached internal FR of the sound card and guide me if it is OK.


----------



## fusseli (May 1, 2007)

Welcome to HTS!

Your soundcard calibration looks like a soundcard calibration :T


----------



## BraveHeart123 (Oct 18, 2010)

fusseli said:


> Welcome to HTS!
> 
> Your soundcard calibration looks like a soundcard calibration :T


Does it mean i crack on with the main thing now? If so, pls be ready for a fusillade of questions :wave:


----------



## fusseli (May 1, 2007)

Haha, yes, carry on! Let's see some FR sweeps and maybe a waterfall plot :bigsmile:


----------



## BraveHeart123 (Oct 18, 2010)

I need to know the initial prep steps before shooting the sweeps. Pls point me if I am wrong. I am listing down the steps as follows;


Disconnect all the speakers except the sub.
Set RS Analog SPL meter on tripod and place at the listening position.
Connect RS SPL meter with Creative SB X-Fi Pro with RCA connector on the SPL meter end and 1/8" stereo male connector on sound card end (Line-in). I have the 1/8" male stereo to RCA female adapter. 
Connect Right Channel (Line-out) from sound crad to any of the Left/Right auxilliary input on the AVR using RCA connectors on both AVR and sound card end. 
Set subwoofer trim level to "00" position in the AVR and set the AVR in "All Channel Stereo" mode.
Turn off Audyssey and Dynamic EQ and/or Dynamic Volume on AVR. Also, turn off all internal sound processing of the sound card so that there is no colouring of the sound signal.
Dial the gain on subwoofer to such a level that subwoofer reads around 85dB on the RS SPL meter at my reference listening volume on AVR. Then leave the main volume dial on AVR at this position and DO NOT touch it till the entire calibration process completes.
Set the RS SPL meter to C-Weighting and Slow Response.
Set the BFD1124p in bypass mode.
Load the the calibration files of (a) internal FR of sound card and (b) RS SPL meter into REW preferences. 


Please let me know if the steps listed above are correct.
One more question, which may be the dumbest of all. Do I need to swtich RS SPL meter ON when connected with sound card through analog RCA?? I am asking this coz there may be wild swings in the FR during frequency sweeps and it might damage the delecate needle. As the SPL dial is fixed when I set it to 75-85dB range.


----------



## fusseli (May 1, 2007)

Ya, it sounds like you are good to go and all setup. The one thing to note is that you may want to disconnect your mains speakers (or use an A/B setting to turn them off) depending on what you are trying to measure, be it subwoofer only or mains + sub. 

I usually calibrate to 75dB SPL, this centers measurements in the desired plot rangeof 45dB-105dB in the REW window. Try it and see if your measurement works with the meter off. Also, I've never heard of an analog meter damaging its own needle...

Once you load the .cal files, REW will remember them the next time so you don't always have to load them first.


----------



## BraveHeart123 (Oct 18, 2010)

Thanx loads. I will take some measurements on this weekend and post my findings here.


----------



## BraveHeart123 (Oct 18, 2010)

Before shooting the sweep, i did the following;

I disabled Audyssey and Dynamic EQ, Set Sub trim level to 00 in AVR, and adjusted the dial on the subwoofer to such a position that the SPL read 85dB at my reference volume at listening position.
 Adjusted the frequency sweeps at -20dBFS in REW.
 Disconnected all the speakers except sub, and kept the crossover to the max in AVR (200Hz). Also disabled the crossover on sub by dialing its xo knob to max (120Hz).
 Put BFD in bypass mode.

Here's my room response.


----------



## BraveHeart123 (Oct 18, 2010)

Can anyone comment on whether the response is fine or not?? Ive been doing the manual calibration and the manual response is roughly the same as with REW. The null at 63hz normally goes away when I add the mains to the sub. 

I need to know the following;


How to let REW automatically calculate filters for BFD DSP1124p?
How to dial in the house curve or hard-knee curve?
What should be the input level in REW preferences? Currently it is set to 1.000. What does 1.000 mean??
My sub (Klipsch SUB-12) has FR between 23-120Hz. How does REW handle the FR when sub-sonic filter on the sub kicks in?? I do not know where does Klipsch employ SS filter on SUB-12.
Should I run Audessy 8 point calibration first, disable Dynamic Voume but leave Audyssey Movie settings enabled, and then calibrate the sub with REW?


----------



## BraveHeart123 (Oct 18, 2010)

fusseli said:


> Ya, it sounds like you are good to go and all setup. The one thing to note is that you may want to disconnect your mains speakers (or use an A/B setting to turn them off) depending on what you are trying to measure, be it subwoofer only or mains + sub.
> 
> I usually calibrate to 75dB SPL, this centers measurements in the desired plot rangeof 45dB-105dB in the REW window. Try it and see if your measurement works with the meter off. Also, I've never heard of an analog meter damaging its own needle...
> 
> Once you load the .cal files, REW will remember them the next time so you don't always have to load them first.


Your comments are awaited....Can anybody else also chime in this thread to help or this is visible only to you???


----------



## JohnM (Apr 11, 2006)

Probably best to start by reading through the help on the EQ window and Communicating with the BFD, and Wayne's Minimal EQ post, linked from the Information Index.


----------



## fusseli (May 1, 2007)

I would say that the FR you posted looks fairly typical for a single sub without EQ. The links John posted should answer your questions. Be sure and post back your results!


----------



## BraveHeart123 (Oct 18, 2010)

fusseli said:


> I would say that the FR you posted looks fairly typical for a single sub without EQ. The links John posted should answer your questions. Be sure and post back your results!


Here is my room's FR with 5 auto eq filters and the 6th manual one added by me at 63.8 hz to remove the dip. I don't think 63.8 hz is a null; it's rather dip. I added 8dB boost there.

I am confused about a couple of things here.

How to add house curve; although I've added a text file in preferences in the frequency/gain fomat seperated by blank space with each pair on seperate line. The first pair is 20 6.0 and 80 0.0 is the second pair on next line. But looking at the graph doesn't show REW has applied any house curve.
How to add main speakers to the sub response?? That is sub+mains. Which bass management to use i.e. in AVR or REW??
I need to see (sub+both mains) response coz I think that 71 hz null will be removed.
Pls guide me step by step on the above mentioned points. I went through all the articles on eq and house curve; but I am not too sure how house curve works. Although ive added the HC file; but seems REW has done nothing in this regard. EQ fileters work fine and the FR shows but not the house curve.


----------



## JohnM (Apr 11, 2006)

BraveHeart123 said:


> How to add house curve; although I've added a text file in preferences in the frequency/gain fomat seperated by blank space with each pair on seperate line. The first pair is 20 6.0 and 80 0.0 is the second pair on next line. But looking at the graph doesn't show REW has applied any house curve.


The house curve is an offset that is added to the target curve, you should see its effect on the target curve in the EQ window



> How to add main speakers to the sub response?? That is sub+mains. Which bass management to use i.e. in AVR or REW??


REW does not have bass management. To measure sub+mains just feed the AVR the test signal from REW, to the left or right input of an AVR analog in, and let the AVR's bass management redirect the signal according to your speaker settings.


----------



## BraveHeart123 (Oct 18, 2010)

JohnM said:


> The house curve is an offset that is added to the target curve, you should see its effect on the target curve in the EQ window


As I understand it, house curve or hard-knee curve is added to the REW in Preferences>House Curve tab. But I am confused how REW applies HC to the response. HC is nothing but EQ filters so it should be part of the seperate EQ window and NOT the preferences. Coz preferences affect all the measurements and EQ window caters for the current measurement only. 

How is house curve fed into the response if there are no matching filters in the EQ window?? I am sorry but I am unable to understand it.


----------



## BraveHeart123 (Oct 18, 2010)

JohnM said:


> REW does not have bass management. To measure sub+mains just feed the AVR the test signal from REW, to the left or right input of an AVR analog in, and let the AVR's bass management redirect the signal according to your speaker settings.


Why does REW ask for Target Defaults in Preferences under Equaliser tab if there is no bass management going on inside REW?? 
What should I do with these settings (Speaker, Cutoff, Crossover, LF Slope, LF cutoff) if REW does not do bass management???

I want sub+main response; pls tell me the setting in preferences. I tried changing the settings in Target Defaults but could only get ouptput from speakers and sub woudn't get any signal.
Also, what should be the setting in "Levels" under SoundCard tab in preferences when I want to measure sub+main response??


----------



## BraveHeart123 (Oct 18, 2010)

Attached is the .mdat file. 

I want a Hard-Knee Curve. My crossover is 80Hz in AVR.
Other gear is listed below;

Klipsch SUB-12 Subwoofer (FR = 23Hz to 120Hz)
Klipsch RF-82 II Mains
Klispch RC-62 II Center
Klipsch RS-52 II Surrounds
BFD DSP1124p
Onkyo 809 AVR

I created a House Curve file and uploaded in REW preferences; but I don't think the EQ filters are doing much to achieve the desired curve. Especially, they are doing nothing below 30Hz though the starting frequency for hard-knee curve is 20. Pls have a look at my .mdat file and suggest on what to do. 
Can anyone help me?? Thanx


----------



## JohnM (Apr 11, 2006)

When REW generates correction filters it attempts to get the filtered measurement as close as possible to an ideal version of what the response would like like with no influence from the room. That ideal response is the target curve. As REW has no way of knowing what it is you have measured, you have to tell it, through the target settings, what kind of ideal response is appropriate. If you measured a subwoofer only, the appropriate target shape would be 'Subwoofer', which reproduces the shape of the low pass response of an AVR bass management filter (it has the same shape as the electrical signal at the AVR's subwoofer output). If you measured a speaker set to 'Small' with the subwoofer turned off, 'Bass Limited' would be the appropriate target shape, which reproduces the high pass shape of an AVR bass management filter (it has the same shape as the electrical signal at the AVR's speaker output). If you measure subwoofer and main speaker together the appropriate target shape would be 'Full Range', which is basically a flat response. 

To save you having to select the correct target shape for every measurement you make in a series of measuring the same thing (for example, the subwoofer on its own) you can set up a default target setting that will be used for each new measurement. Those settings are in the Equaliser preferences.

Although the target settings reproduce the ideal response, we may want something different - for example, we may prefer a gentle rise at the lowest frequencies. To cater for that a 'House Curve' can be selected. The House Curve response is added to the ideal target response, so that the target has the shape we would like to see. REW's EQ filter generation will then try to match that preferred shape rather than the ideal target response. The house curve is added to all versions of the target response.

Note that REW will not generate boost filters at frequencies below the lowest point at which the measurement drops below the target. For example, if the target was flat at 75dB all the way to 2Hz, but the measurement drops below 75dB at 30Hz and never goes back above it, REW will not generate any filters lower than 30Hz. That is to avoid boosting a subwoofer or speaker below its natural roll-off, as that might over-stress the driver. You can manually add filters if you wish to boost the response below the roll-off.


----------



## BraveHeart123 (Oct 18, 2010)

Thanx John, I followed your advice and the results are nothing short of tremendous in the lower frequency spectrum. Pls have a look at the following FRs (Raw, Sub Only, and Sub+Mains) with 80 Hz crossover and Filter Range between 20Hz to 70 Hz in the EQ setting of REW (As per a write-up on house curve from Wayne).

The region near crossover is a bit ruffled up, but down below 60Hz it's fantastic. Could you pls advise on how to tackle those huge ripples near 80Hz??? May be I should raise or lower the crossover from 80Hz. 

Also, how does the "Find Resonances" option work in Modal Analysis?? I mean is there any upper limit in milliseconds that the ringing must not go beyond??? Your advice is sought....


----------



## JohnM (Apr 11, 2006)

BraveHeart123 said:


> The region near crossover is a bit ruffled up, but down below 60Hz it's fantastic. Could you pls advise on how to tackle those huge ripples near 80Hz??? May be I should raise or lower the crossover from 80Hz.


You might have more success experimenting with placement, of the subwoofer and/or listening position. Also worth making a measurement with a main speaker to see what effect that has.



> Also, how does the "Find Resonances" option work in Modal Analysis?? I mean is there any upper limit in milliseconds that the ringing must not go beyond??? Your advice is sought....


It carries out an analysis of the measurement, the results can be used to more precisely target filters to address specific resonances by using the 'Modal' filter setting. In most circumstances you can simply use REW's automatic filter setting and ignore the modal analysis.


----------



## BraveHeart123 (Oct 18, 2010)

Those ripples between 70 and 80 hz are due to the sub location and I am afraid I have to live with them coz that's the only location the sub can go in my bedroom. Anyway, apart from that the response now is nothing less than ballistic.

One thing more....ur signature says u are the owner of REW....if that means u did all the backend programming; u've done an outstandingly tremendous job, especially the filters setting part as that is the most important business end. 
Even if u haven't done the programming but own the idea; that itself earns u galactic praise all over the HT enthusiasts' world.

REW is dead on in accuracy and it has made my job a breeze. Thanx tons for your help and a great calibration programme. Bravo .... Hail John


----------

