# My first measure



## sonata31 (Jun 2, 2006)

I made my first measure of my sub :









When I click on Find Peak I get the message :

_Largest peak found was 29,6dB
Target Level may bet set incorrectly (too low)_

Yet the Target Level = 80.5dB

??


----------



## terry j (Jul 31, 2006)

*Re: My first mesure*

have a look at the frequency range under the find peaks button. You may have the upper figure too high, eg at ( say) 100 hz you may have a signal at 100 db, but the target curve at that frequency may be at 60 hz, giving you a peak of 40 hz. In all likelihood the upper figure will be something like 200 hz, try setting it to 100 hz or a more appropriate figure,

lots of love

terry


----------



## brucek (Apr 11, 2006)

*Re: My first mesure*



> I made my first mesure of my sub :


Is this the sub alone or sub plus mains?

What is the crossover setting for your system?

brucek


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*



brucek said:


> Is this the sub alone or sub plus mains?
> 
> What is the crossover setting for your system?
> 
> brucek


Sub alone

The results of Find Peak depend of the Cutoff parameter ?
What value for Cutoff with this response ?


----------



## brucek (Apr 11, 2006)

*Re: My first mesure*



> The results of Find Peak depend of the Cutoff parameter ?


Yes.

You are showing a target cutoff for filter suggestion at 60Hz. Is that the crossover setting on your system, because it looks more like 80Hz as shown in the overlay below where I added a 80Hz line...



> What value for Cutoff with this response ?


Set it to the crossover value set in your receiver.










brucek


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*

My connections are :

Ampli Yam (used like pre-ampli) --> DCX2496 --> DEQ2496 --> Ampli --> Front
|------------------------|------------|--------------------> DEQ2496 --------------> Sub
|------------------------|---------------------------------> DEQ2496 --> Ampli --> Centre
|------------------------|---------------------------------> DEQ2496 --> Ampli --> Surrounds
|--------------------------------------------------------------------------------> Surrounds back

This for use my sub in Hi-Fi (mode stereo pure direct on the Yam)

For the test the DCX is bypassed (no crossover), the DEQ is bypassed (no PEQ) and the ampli of front is turned off


----------



## brucek (Apr 11, 2006)

*Re: My first mesure*

Turn on the DCX and set it to the crossover value set in your receiver DCX2496.


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*



brucek said:


> Turn on the DCX and set it to the crossover value set in your receiver DCX2496.


60Hz or 80Hz ?


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*

Cutoff on REW and crossover on DCX = 60









Cutoff on REW and crossover on DCX = 80









And now ?


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*

Crossover on DCX at 24dB instead of 12dB

Cutoff on REW and crossover on DCX = 60









Cutoff on REW and crossover on DCX = 80









And now ?


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*

Cutoff on REW and crossover on DCX = 40


----------



## brucek (Apr 11, 2006)

*Re: My first mesure*



> 60Hz or 80Hz ?


Well, this is something you don't ask for an opinion on. It is really determined (demanded) by the speakers you are using. 

If the mains speakers have a -3dB down response to 40Hz (for example), you would set the crossover at an octave above that. So they would have to be extremely capable speakers to choose a crossover below 80Hz. That's the preferred crossover. You'll obviously have less equalization control if anything less is chosen.

Subwoofer crossovers are forced at the upper end, so generally set at a fourth order LP and so -24dB per octave would be suitable. For the mains which enjoy a natural falling off at the lower end, then a second order -12dB per octave would be correct.

The cutoff in REW is always set to match the crossover frequency.

brucek


----------



## JohnM (Apr 11, 2006)

*Re: My first mesure*

The subwoofer target response on REW is based on a 24dB/octave roll-off, per THX recommendations for bass management, which is why you see a better match between actual and target shapes with the DCX set to 24dB.


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*

With cutoff=80Hz, what values for Find Peak ?


----------



## brucek (Apr 11, 2006)

> With cutoff=80Hz, what values for Find Peak ?


20Hz to 200Hz....


----------



## sonata31 (Jun 2, 2006)

Thank You for your responses


----------



## sonata31 (Jun 2, 2006)

Test after Find Peak and Optimize PK Gain & Q









Test after transfer the settings in the DCX









Is it good ?

How reduce the hole at 30Hz ?


----------



## brucek (Apr 11, 2006)

> Is it good ?


Oui, très bien....



> How reduce the hole at 30Hz ?


That's hard. Your best bet is to move the sub around a bit. A corner is preferred...

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Oui, très bien....


Good French :T 




> That's hard. Your best bet is to move the sub around a bit. A corner is preferred...
> 
> brucek


I Can't move my sub, because WAF :

















A filter PEQ with 7-8dB is correct ?


----------



## brucek (Apr 11, 2006)

> I Can't move my sub, because WAF


Definitely swap the sub and main in that corner. The main doesn't like the corner and the sub does.... Your wife will never notice....



> A filter PEQ with 7-8dB is correct ?


Don't really understand the question?

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Definitely swap the sub and main in that corner. The main doesn't like the corner and the sub does.... Your wife will never notice....


I can't swap the sub and main because the screen




> Don't really understand the question?
> 
> brucek


A filter at 30Hz with a gain=7-8dB ?


----------



## sonata31 (Jun 2, 2006)

With a filter at 30Hz, gain=+5dB


----------



## brucek (Apr 11, 2006)

> With a filter at 30Hz, gain=+5dB


That's as high as I would go... no more than +5dB.

Reduce the area from 40Hz to 80Hz a little bit and you're done.....

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> That's as high as I would go... no more than +5dB.
> 
> Reduce the area from 40Hz to 80Hz a little bit and you're done.....
> 
> brucek


I have already set filters to the DCX !!!


----------



## brucek (Apr 11, 2006)

> I have already set filters to the DCX !!!


Can you not manually adjust them once they are sent?

Dial down the filter gain in that area a few dB and remeasure...

If you saved the unfiltered .mdat file and the filter .req file, then you can play with the filters manually in REW to see the effect...

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Can you not manually adjust them once they are sent?
> 
> Dial down the filter gain in that area a few dB and remeasure...
> 
> ...


Ok, but all the day to mesure, it's a lot
I will continue later

Thank for yoyr responses


----------



## sonata31 (Jun 2, 2006)

*Re: My first mesure*



brucek said:


> ...
> 
> If the mains speakers have a -3dB down response to 40Hz (for example), you would set the crossover at an octave above that. So they would have to be extremely capable speakers to choose a crossover below 80Hz. That's the preferred crossover. You'll obviously have less equalization control if anything less is chosen.
> 
> ...



In the user guide of the B&W ASW650 (my sub) : 









My B&W DM604 (my front) :
39Hz - 22kHz ± 3dB on reference axis
-6dB at 30Hz and 42kHz

So for Brucek crossover = 80Hz, and for B&W crossover = 30Hz

Which of the two crossover is the good ?


----------



## brucek (Apr 11, 2006)

> Which of the two crossover is the good ?


80Hz....... this will ensure a smooth transition. If you set the bass low pass to 30Hz, how would you equalize the subwoofer. THX recommends 80Hz.

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> 80Hz....... this will ensure a smooth transition. If you set the bass low pass to 30Hz, how would you equalize the subwoofer. THX recommends 80Hz.
> 
> brucek


Ok, Thank You


----------



## sonata31 (Jun 2, 2006)

When I measure with the crossover set at 40Hz, 60Hz or 80Hz the Target Level is not the same. Do I adjust the level of my ampli to have the same target level for the three measures ?


----------



## brucek (Apr 11, 2006)

> Do I adjust the level of my ampli to have the same target level for the three measures ?


Yes...

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Yes...
> 
> brucek


Thank You


----------



## sonata31 (Jun 2, 2006)

Measure sub + front for choice of the good crossover frequency

Crossover = 40Hz









Crossover = 60Hz









Crossover = 80Hz









What is the good crossover frequency ?


----------



## sonata31 (Jun 2, 2006)

Sub + front with crossover = 40Hz with level on the sub

+5dB on the sub









+10dB on the sub









+15dB on the sub


----------



## sonata31 (Jun 2, 2006)

Sub + front with crossover = 60Hz with level on the sub

+5dB on the sub









+10dB on the sub









+15dB on the sub


----------



## sonata31 (Jun 2, 2006)

Sub + front with crossover = 80Hz with level on the sub

+5dB on the sub









+10dB on the sub









+15dB on the sub


----------



## sonata31 (Jun 2, 2006)

There is an error : I have erased the graph, sorry


----------



## sonata31 (Jun 2, 2006)

Help :sad2:


----------



## brucek (Apr 11, 2006)

> Help


80Hz............

brucek


----------



## sonata31 (Jun 2, 2006)

I have updated all my graphs because an error

Is 80Hz always the good crossover frequency ?


----------



## brucek (Apr 11, 2006)

> Is 80Hz always the good crossover frequency ?


Yes, unless the mains aren't capable of extending low enough. This would be the case with small satellites. The problem there would be that a crossover higher than 80Hz causes the subwoofer to be localized. 

Not many mains allow setting the crossover to less than 80Hz. The lower crossover reduces the ability to equalize in the area that is quite important.

Using 80Hz is your best bet.

brucek


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Yes, unless the mains aren't capable of extending low enough. This would be the case with small satellites. The problem there would be that a crossover higher than 80Hz causes the subwoofer to be localized.
> 
> Not many mains allow setting the crossover to less than 80Hz. The lower crossover reduces the ability to equalize in the area that is quite important.
> 
> ...


My mains are the B&W DM604 : 39Hz - 22kHz ± 3dB

With 80Hz what level on the sub : 0dB, 5dB, 10dB or 15dB ?


----------



## brucek (Apr 11, 2006)

> With 80Hz what level on the sub : 0dB, 5dB, 10dB or 15dB ?


Whatever sounds right to you. There is no rule there...

brucek


----------



## sonata31 (Jun 2, 2006)

Sub calibrated alone with crossover frequency = 80Hz, level = +10dB

response









filters









Is it good ?


----------



## sonata31 (Jun 2, 2006)

Sub calibrated alone with crossover frequency = 80Hz, level = +10dB, with filters in the DEQ2496


----------



## brucek (Apr 11, 2006)

> Is it good ?


Yep, it's quite good....

brucek


----------



## sonata31 (Jun 2, 2006)

I don't understand anything : with this previous filters settings the sub is very high in comparaison with the mains

Here is the response of the mains alone, without calibration, with crossover frequency = 20Hz









Is 80Hz for the crossover frequency a good choice ?


----------



## brucek (Apr 11, 2006)

> Is 80Hz for the crossover frequency a good choice ?


Yes


----------



## sonata31 (Jun 2, 2006)

brucek said:


> Yes


Thank You for your responses et your patience 

I abandon for today :yawn:


----------

