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CE 400 High and Low Pass Filter Settings


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#1 Cory Cooper

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Posted 01 June 2006 - 05:07 AM

Hi,

Here's my system:

Rane MP 24z
Denon DN-2000F
dbx DriveRack PA
(2) Crown CE 4000
(2) JBL MPro MP415
(2) JBL MPro MP418S

I used the DRPA wizard and set everything up with the defaults by choosing my equipment, setting the amp sensitivity at 1.4V (amp and DRPA) and the front panel amp levels to 54% as default in wizard shows. Crossover defaults are 45Hz and 125Hz (although I prefer 40Hz and 95Hz).

Just a quick question. Is there/would there be any benefit to changing the default settings of FLAT  for the high and low pass filters on the back of the CE 4000s? Because the DRPA has an active crossover built-in and setup, would it actually be a negative effect to set the high pass to say 30Hz for the CE running the 418S subs, and a low pass of say 80Hz for the CE running the 415s? Would this reduce the strain on the amps and help the speaks breathe a little easier?

Thanks in advance,

C

#2 DGlass

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Posted 01 June 2006 - 09:41 AM

Putting the 30Hz HP amp filter in probably wouldn’t hurt anything as the dbx system filter is already LF High Passed at 45 Hz (which is higher in frequency) so the dbx system filter would already be cutting anything below 45Hz were the 30Hz filter would be.

Putting in the amps 80Hz LP filter would cause a big problem as it would block anything above 80Hz from getting to the speakers as it wants to pass everything below 80Hz. Since this is the top box and the dbx system crossover is set to pass anything above 125Hz the MP415 speakers would be getting nothing,

I would use the dbx DRPA for you system filters and leave the amp on Flat. You can play around a little with x-over frequency settings, in the dbx, dropping it to 95Hz if you like (This would be both the LF LP and the HF HP filters that are defaulted to125Hz). I would however leave the LF HP filter alone as the frequency response of the MP418s begins at about 40HZ. smile.gif

#3 Cory Cooper

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Posted 01 June 2006 - 02:26 PM

Ooops...I guess I posted the wrong info...got the filters confused. Man I do that a lot!

I meant the following:

418S Sub CE 4000: High Pass of 30 and Low Pass of 100
415 CE 4000: High Pass of 50

That would give the subs freqs between 30 and 100 and the tops freqs above 50, correct?

Thanks for you previous reply,

C

#4 DGlass

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Posted 01 June 2006 - 04:29 PM

QUOTE(Cory Cooper @ Jun 1 2006, 02:26 PM)
Ooops...I guess I posted the wrong info...got the filters confused. Man I do that a lot!

I meant the following:

418S Sub CE 4000: High Pass of 30 and Low Pass of 100
415 CE 4000: High Pass of 50

That would give the subs freqs between 30 and 100 and the tops freqs above 50, correct?

Thanks for you previous reply,

C
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Lets look at what you want to do:

On the subs.. the 30Hz HP amp filter will still not make a difference because the dbx system filter is at 45Hz. This 45 Hz HP filter is blocking anything below 45Hz from going to the amp already so putting a filter in at 30Hz doesn't do a thing.
The 125Hz LP filter for the subs, in the dbx unit, is passing frequencies below 125Hz to the sub amp so using the 100Hz LP filter in the amp will additionally block the frequencies between 100 and 125Hz. huh.gif

Now lets look at the HF HP filters. The dbx is crossing over at 125Hz and if you use an amp HP filter at 80Hz you will see no change in the HF as the amp is only getting frequencies from 125Hz and up from the DRPA.  dry.gif

The only thing you will do with these settings is knockout the sub from producing frequencies between 100-125Hz leaving a hole in your Subs sound. sad.gif

The filters on the amp are there for people who don't have a x-over or processor like the DRPA as a simple way to have a down and dirty x-over. You will not gain anything by using the amplifier filters with the DRPA filters. I would set the DRPA sub LP to 90Hz or 100Hz and the HF HP filter to the same frequency and leave the amps Flat. It will be the easiest way to accomplish what you are wanting to do. smile.gif

Also after looking at the Frequency Responce Graph and Frequency Specifications of the MP418, on it's data sheet, I wouldn't set the sub HP filter below 40 Hz. At 36Hz the output is already down 10db.

#5 Bud Bolf

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Posted 01 June 2006 - 06:17 PM

Howdy,
I have a DriveRackPA and a CE4000 power amp.
I set up as follows.
On my DriveRack I set the HPF to 50Hz I do this because I never really noticed a Big difference between 40 and 50Hz and my Dual 15 Subs and they Kick nice and hard at 50Hz.
On my CE4000 I set the HPF filter to 40Hz, and I'll tell you why.
One thing that David did not mention about the Filters, is that when you set the Filters on the DRPA and the CE4000 you also set the Slope!
The Slope is how gradual or not the Frequencies actually decrease from the Filter setting.
To say that if I set my Crossover HPF to 50HZ and there will not be any Frequencies below that point is not really correct.
If I set the Slope at a Gradual decline, I can hit Frequencies at 40Hz, 30Hz or less.
A simple example would be:
Think of standing at the top of a mountain and you are at 50Hz and if you look over the edge it drops straight down, then that is a very very steep Slope and your 50Hz has nowhere to go.
Now, what if on the other side of the mountain it declined by about a 45 degree angle and was much more Gradual, as if you could Ski down it.
Picture that half way down there was a sign of 30Hz, because that slope did not drop right off, as your output dB increases and overpower's let's say a -18dB Slope, you can actually run your Speakers into much lower frequencies, where they were not designed to go!
The DRPA's steepest slope is I believe -24dB but the DriveRack 260 can go to -48dB.
That is obviously twice as steep of a Slope as a -24dB Slope!
In other words a -24dB slope is good but it is not a brick wall per say, that will not allow any Frequencies below what it is set at to pass.

Though I set my DRPA's HPF to 50Hz at -24dB Linkweitz-Riley Filter, I set the CE4000 to 40Hz for the HPF to help with any Frequencies that would extend past 50Hz from my DriveRack.
My Subs are rated at 35Hz and I feel that 50Hz to 40Hz HPF they are safe and I know so, since I am Hitting them with the CE4000 Bridged at 4 ohms and 2800 watts, they can run there all day and night and have!
With a steeper Slope I could lower my HPF's but I am very happy with where they are.
Could I get away with setting the CE4000 at FLAT, probably, I'll let David answer that.
However, I also read in the Manual that if you are not using frequencies lower than one of the Filter sets, especially in the low end, then set the HPF Filter, by doing so the CE4000 will work harder to reproduce Low Frequencies that it does not need to!


QUOTE
5.1.3 High-Pass Filters
Very low frequency signals contain no useful
musical energy, waste valuable amplifier power
and headroom, and can be damaging to
your speakers.


My LPF on the other hand, I leave FLAT at the amp, I do this so I can find the sweet spot between my Subs and Top Cabs and do not want the CE4000 filter mucking up my settings.

There is so much to know about Crossover Filters, Frequencies, and Slopes.
The Crossover point between your Subs and Top cabs will not always be the same such as 100Hz LPF for the Subs and 100Hz HPF on your top cabs, due to the slope's you would have cancellations between the two cabs as the Frequencies cross.

You are in great shape though because you are matching two JBL cabs and the Tunings are in the DriveRack.
If you have Crossover questions you should be able to find the exact settings at the JBL website or call their Tech Support and I'm sure that they will give you the Exact Crossover points, Filter, Slopes everything.

In the end with the JBL's and the DriveRack I would probably leave the Filters FLAT, unless you want to do as I did and use the HPF as a safety measure.

Good luck,
      Bud

#6 Bud Bolf

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Posted 01 June 2006 - 06:47 PM

Hi again,
As I said in my previous post, JBL will give you the Exact Crossover settings but where you said this:

QUOTE
418S Sub CE 4000: High Pass of 30 and Low Pass of 100
415 CE 4000: High Pass of 50
That would give the subs freqs between 30 and 100 and the tops freqs above 50, correct?


In short NO!
In long version, you would never want to Cross your Top cabs so low into the Subs frequencies or your Sub Frequencies into your top cabs.
There is a reason that the process is called, Crossover or Crossing Over!
You want to very smoothly transfer the 40Hz to 20kHz of the Musical spectrum
between the two cabs.
You do not want to CrashOver the Frequencies between the two cabs.
If you set the HPF on the MP415's to 50Hz then you are running the top cabs 50Hz into the Subs!
What Frequencies do you want the Subs (MP418's) to handle and what for the MP415's?
Your just crashing them together, and this will cause terrible results and Freq. Cancellations.
Your missing the whole point of what a Crossover is for!

There is a whole lotta knowledge here:
ProSoundWeb's Lab Lounge

Check out the Study Hall:
PSW Study Hall

Check out Audio Basics first:
PSW Audio Basics

If you did not already check out the DBX DriveRack Forums
Here is a Link: DriveRack Forum
Try a Search also.

You can also use Michael "Bink" Knowles, Audio Test CD,
to help you refine your System.
It's a great tool, check it out here: Bink's Audio Test CD
Check out the rest of his Site too, interesting stuff!

This should keep you busy for awhile, but well worth it, the more that you can improve
your Live Sound Knowledge and put it to use, you will Hear the Difference!
Feel the Confidence and just want to learn more!

Good Luck,
     Bud

#7 Cory Cooper

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Posted 01 June 2006 - 10:09 PM

Thanks to all. Have been using the system for two years with the CE HP and LP all on flat.

I have the Bink CD...I used it to setup gain structure thru the system.

Really, was just curious about the filters built into the amps...the DRPA handles all the crossover settings for me.

Thanks again,

C

#8 Bud Bolf

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Posted 02 June 2006 - 08:40 PM

QUOTE(Cory Cooper @ Jun 1 2006, 11:09 PM)
Thanks to all. Have been using the system for two years with the CE HP and LP all on flat.

I have the Bink CD...I used it to setup gain structure thru the system.

Really, was just curious about the filters built into the amps...the DRPA handles all the crossover settings for me.

Thanks again,

C
View Post


C,
Now I'm feeling used!
Were you just testing US?

What was with this, since you already know that it is a Bogus Post:

QUOTE
Ooops...I guess I posted the wrong info...got the filters confused. Man I do that a lot!

I meant the following:

418S Sub CE 4000: High Pass of 30 and Low Pass of 100
415 CE 4000: High Pass of 50

That would give the subs freqs between 30 and 100 and the tops freqs above 50, correct?

Thanks for you previous reply,

C


If you have been using the System for 2 years then you know that these Crossover settings are wrong for the JBL cabs specified!
If you already knew this then why keep asking questions?
Now I'm confused by this entire post!
If all you needed to know was about the CE4000 filters, then this post would have been over after David's first response.

Later,
   Bud

#9 Cory Cooper

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Posted 02 June 2006 - 09:55 PM

Bud,

Ease up a little...this is not a bogus post. I am not "playing", "testing", or trying to waste anyone's time. I don't appreciate your tone. This is a help forum, I needed some help, so I posted to get some.

I think I might have confused some folks...so let me try to explain where I am coming from again. I am not a sound pro like many of the folks here and on the ProSoundWeb and DriveRack forums. That's why I asked the question(s)...to learn.

As I said, I have been using the system for two years - just using the crossover in the DRPA and running the HPF & LPF on the two CE 4000 amps on the FLAT setting. I was just curious about using the HPF & LPF on the amps, in addition to the crossover filters on the DRPA, if I would see any benefit.

My crossover settings in the DRPA are as follows, customized slightly from the DRPA Wizard setup defaults - shown in parentheses:

Low
40Hz BW18 (45Hz BW12)
95Hz BW24 (125Hz BW24)

High
95Hz BW24 (125Hz BW24)

I lowered the crossover point to 95Hz because it sounds better to me in most situations, and was recommended by a member on another forum when I first got the DRPA, as well as confirmed in the first reply from David.

As you can tell, I mixed up high-pass and low-pass in my posts, which I am sure made everyone think I was totally out of my mind.

From the responses I received here, I have determined the following to be best:

1. Let the DRPA do the crossover work for the system.
2. Setting the CE 4000 HPF on 30Hz for the CE 4000 running the two 418S subs and 40Hz on the CE 4000 running the two 415 tops instead of on flat is simply an extra form of filtering on top of the settings in the DRPA - as you explained in your first post as a safety measure. These are both below the bottom limit of the respective cabinet's effective frequency response.
3. Leave the LPF on both amps on the FLAT setting.

Correct?

Sorry I confused everyone, just trying to learn a little more. Everyone's explanations are much appreciated and I now have a much better understanding.

Thanks again,

C

#10 Bud Bolf

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Posted 02 June 2006 - 11:47 PM

QUOTE(Cory Cooper @ Jun 2 2006, 10:55 PM)
Bud,

Ease up a little...this is not a bogus post. I am not "playing", "testing", or trying to waste anyone's time. I don't appreciate your tone. This is a help forum, I needed some help, so I posted to get some.

I think I might have confused some folks...so let me try to explain where I am coming from again. I am not a sound pro like many of the folks here and on the ProSoundWeb and DriveRack forums. That's why I asked the question(s)...to learn.

As I said, I have been using the system for two years - just using the crossover in the DRPA and running the HPF & LPF on the two CE 4000 amps on the FLAT setting. I was just curious about using the HPF & LPF on the amps, in addition to the crossover filters on the DRPA, if I would see any benefit.

My crossover settings in the DRPA are as follows, customized slightly from the DRPA Wizard setup defaults - shown in parentheses:

Low
40Hz BW18 (45Hz BW12)
95Hz BW24 (125Hz BW24)

High
95Hz BW24 (125Hz BW24)

I lowered the crossover point to 95Hz because it sounds better to me in most situations, and was recommended by a member on another forum when I first got the DRPA, as well as confirmed in the first reply from David.

As you can tell, I mixed up high-pass and low-pass in my posts, which I am sure made everyone think I was totally out of my mind.

From the responses I received here, I have determined the following to be best:

1. Let the DRPA do the crossover work for the system.
2. Setting the CE 4000 HPF on 30Hz for the CE 4000 running the two 418S subs and 40Hz on the CE 4000 running the two 415 tops instead of on flat is simply an extra form of filtering on top of the settings in the DRPA - as you explained in your first post as a safety measure. These are both below the bottom limit of the respective cabinet's effective frequency response.
3. Leave the LPF on both amps on the FLAT setting.

Correct?

Sorry I confused everyone, just trying to learn a little more. Everyone's explanations are much appreciated and I now have a much better understanding.

Thanks again,

C
View Post


Hi C,
It just struck me that after all was said and done it was like, "Been there done that"  sort of thing.
If I was wrong then my apologies.

Back on line and looking at your settings, I agree that 125Hz for the LPF on your Subs does sound a bit high and I would imagine that at 125Hz you would start to hear vocals in your Subs.

QUOTE
40Hz BW18 (45Hz BW12)


The Butterworth -12dB at 45Hz seems like a pretty gradual slope for your subs.
Be careful with the 40Hz -18dB on your subs even though you raised the down slope level by -6dB, you still reach into the 30's when pushing the Subs.

Have you set up 2 user presets in your DriveRack, one for the JBL settings and one modified by you?
Then you can quickly switch between them and compare.
Not that JBL got it wrong but it makes me think Hmmm I wonder what's up with
the JBL settings.
JBL must have set their parameters the way that they did for a reason.

Another note is that I believe that the CE4000 uses Linkweitz-Riley filters and you are using a Butterworth Filter, what effect that would have at 30Hz is probably negligable but if it was in the 95Hz LPF to HPF region that would not be good.

When you use the DriveRack tunings for your speakers it should also set your Parametric's and I hope that changing your Crossover settings does not poorly react with your PEQ.

Later,
    Bud

#11 Cory Cooper

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Posted 03 June 2006 - 12:19 AM

No worries Bud. I have always found it easier to understand, learn, and retain info from folks that know the ins and outs vs books and such. I just have the gift of jumbling my thoughts/goal between brain and keyboard.  wink.gif  Most of the time I know just enough about something to be dangerous.

Yeah, the BW12 is a little gradual, but that's the default from the DRPA Wizard for my speakers and amps. I figured by at least upping it to BW18 when I dropped the freq from 45Hz to 40Hz it would be enough. Maybe a BW24 would be better at 40Hz?

I did a little more reading into the Linkwitz-Riley vs Butterworth crossovers. I see now that LR are flat at the crossover point and BW have a peak at said crossover point. Maybe I should run all LW? The DRPA only gives the option of LW12 and LW24. Guess it would be LW24.

Yes, I have a preset with just the settings for my equipment as the DRPA Wizard sets them, then I saved my custom settings in another preset. Mine sounds smoother and fuller in the low-end, as well as slightly deeper. Much more pleasing to the ear.

The Wizard does set a PEQ for both sets of speakers...I have just left those as is.

Thanks again for the info...it really is helpful. Guess I shouldn't even go into the phase shift between the different orders huh?  wink.gif

C