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Discussion Starter · #1 ·
I run a Danley DTS-10 with a Behringer EP4000 for power and a Behringer Frequency Destroyer for EQ.


I believe I read using a high pass to limit low frequencies to the sub that it can not produce has value. Since I can not produce significant SPL below about 15 hz I would like to limit the signal.


Here is the in room response of the sub only from my 3 main seats.



I can't make a high pass filter is the BFD, can I? I believe not, it appears I can with the Mini-DSP I have been reading about.


Can I replace the BFD and get the high pass filter and EQ out of the mini DSP?


Please excuse me if my terminology is off this is still a little new to me.
 

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The DTS-10 has an 11Hz knee, but youre sayin you dont get much below 15Hz? Glad I didnt get them... mine shines from 5Hz-15Hz and thats the stuff I LOVE. On the flip side, my EP4000s and the rest of my chain cause me to not need any HP. I only bottom above tuning.
 

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Everyones room will be different, MK got much lower response. I don't have a high pass on mine and I played the Incredible Hulk, the scene where Hulk is pounding Abomination with the cop car (Bosso reported that to be brutal down low) and I feel it strong without issue. I've never had it bottom out on any material ever thrown at it. Maybe having them nearfield helps.
 

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In that case I would not HP them. That sceen is my favorite, making this movie over WOTWs for me personally. If those bad boys can get down there, you guys have some sweet tapped horns. Wish one of you guys was camera happy like me and made some good vids. Sure you cant see the drivers, but bouncing fan blades, bouncing ceilings, flopping doors, and neighbors windows vibrating subsonicly demonstrate very well whats going on.
 

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Discussion Starter · #7 ·
Quote:
Originally Posted by noah katz
In effect you can by cascading boost starting at 20 Hz to raise everything except the very low end.


BTW, the F in BFD is for "feedback"
Thanks Noah, I always seem to think the F is for Frequency because that is what I use it for.


Can you further explain cascading boost and how to implement it?


The Mini DSP seems like it would do the job but the information is thin.

http://www.minidsp.com/
http://www.minidsp.com/images/docume...02x4%20Box.pdf


It says Parametric EQ and HP LP filters but again the information is thin. For $125 I may pick one up to play with it. It seems like a good sub manual EQ amoung other things.
 

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I use a 48hz. slope at 12 hz. I think that is what Ivan recommended. I also use an x-over (12 hz slope) at 120hz, because I run my speakers large and double bass. I have heard some nasty things (Iron Man) above about 150hz.
 

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Quote:
Originally Posted by t6902wf /forum/post/19624449


Thanks Noah, I always seem to think the F is for Frequency because that is what I use it for.


Can you further explain cascading boost and how to implement it?


The Mini DSP seems like it would do the job but the information is thin.

http://www.minidsp.com/
http://www.minidsp.com/images/docume...02x4%20Box.pdf


It says Parametric EQ and HP LP filters but again the information is thin. For $125 I may pick one up to play with it. It seems like a good sub manual EQ amoung other things.

I have two MiniDSPs now, very powerful little devices (more powerful in terms of EQing then the DCX). Your total cost for it is closer to $170 with shipping and software purchase.


It has an advanced mode where you can just enter biquad values. These values are used in transfer functions which means you can build any slope with any Q you want at any frequency.


My MiniDSP thread had a link to downloading a spreadsheet that gives you the High Passfilter biquad values.


NOTE: I have not tested the MiniDSP with very low frequencies yet.
 

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Discussion Starter · #10 ·

Quote:
Originally Posted by Wrager /forum/post/19624743


I use a 48hz. slope at 12 hz. I think that is what Ivan recommended. I also use an x-over (12 hz slope) at 120hz, because I run my speakers large and double bass. I have heard some nasty things (Iron Man) above about 150hz.

I don't have a devise that will allow me EQ down that low. But I am working on it.
 

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Discussion Starter · #11 ·

Quote:
Originally Posted by penngray /forum/post/19624940


I have two MiniDSPs now, very powerful little devices (more powerful in terms of EQing then the DCX). Your total cost for it is closer to $170 with shipping and software purchase.


It has an advanced mode where you can just enter biquad values. These values are used in transfer functions which means you can build any slope with any Q you want at any frequency.


My MiniDSP thread had a link to downloading a spreadsheet that gives you the High Passfilter biquad values.


NOTE: I have not tested the MiniDSP with very low frequencies yet.


Thanks for the input I will look into it.
 

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Quote:
Originally Posted by t6902wf /forum/post/19624449


Can you further explain cascading boost and how to implement it?

By boosting everything above 20 Hz with broad low Q filters you essentially create a HP filter.


Not sure what effective slope you can get.


You can use s/w to enter your BFD's filters and see.


Not sure what if anything that does to SQ in the boosted range.


Another option is a Reckhorn B-2 or the previous B-1 (check ebay).

http://www.reckhorn.com/index.php?ln=en&prod=b2
 

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One thing to keep in mind, when talking about low low a particular sub goes (and the "measured" response) is the quality of the microphone being used.


People just assume (you know what happens when you do that), that their mic is "flat" to as low as they want to go-along with the rest of the measurement system.


If properly measured and compared to a truly flat response, you may be suprised at how "off" the measurements are.


Mics that are flat down below 20Hz are expensive. And I doubt most of the people have spent $600 on just the measurement mic.


So the "measured" results are not going to be accurate-yet people make lots of claims as if they were.


Just something to think about.
 

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Ivan, $60 mics can be professionally calibrated down to 5Hz for about $30.


Assuming the calibration is accurate what is the difference after that calibration between the $90 mic and the $600 mic?
 

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Quote:
Originally Posted by penngray /forum/post/19630043


Ivan, $60 mics can be professionally calibrated down to 5Hz for about $30.


Assuming the calibration is accurate what is the difference after that calibration between the $90 mic and the $600 mic?

It is one thing to have a mic that has a calibration file (but you have to be able to put that file into the measurement program in order to have it "return" to flat or make any sense), and another to have a mic that has a flat response down that low naturally and flat.


The phase response is another big issue that seperates the low cost mics from the more expensive units.


There are a number of manufacturers who use the same elements (and often the same style/type casings) as the cheap units, BUT they have included a good bit of compensation electronics in the package to address the response and amplitude issues that the cheaper units don't have.


SPL is another area in which the cheaper mics can vary quite a bit. So the "claims" of SPL will often be off, usless the particular mic has been calibrated (with a calibrator) before measurements.


At the Southern sub get together about 1 1/2 years ago at Brandons house, we had a fair number of SPL meters that we compared and found to be a fair bit of difference between them. So which one was "correct"? I had sent mine in for calibration not that long before, so I would assume that it was the closest. And just because mine costs several times more than all of the others put together does not mean it was more accurate, but the tendancy would be to think so.


It is a real common problem now a days for people to "believe" what they see on a computer screen is actually accurate or correct. But there are all sorts of variables that can get in the way of accuracy.


You ALWAYS have to question the measurement. If it doesn't look correct, it may not be. Just don't blindly accept what the computer screen shows.


I have had MANY times that I have "measured" a loudspeaker and something just didn't seem right. So after checking around, the error was found and then the new measurements were more believable.


Remember that everything in the chain is part of a "system" and any limitation in any part of that system will affect the final result.
 

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Discussion Starter · #17 ·
Thanks for the comments Ivan. This measurement happened to be taken with a galaxy C140 meter with a generic correction file. Is it accurate? Probably not but it is helpful in establishing eq settings.


Would you care to comment on the original question. What is the value of the hi pass on the DTS 10?
 

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Quote:
Originally Posted by t6902wf /forum/post/19630758


Thanks for the comments Ivan. This measurement happened to be taken with a galaxy C140 meter with a generic correction file. Is it accurate? Probably not but it is helpful in establishing eq settings.


Would you care to comment on the original question. What is the value of the hi pass on the DTS 10?

EVERY LOUDSPEAKER should be operated with a high pass filter-especially if pushed anywhere near its limit.


When you operate below where the driver is "tuned" or the intended range of operation, it will "flop around" which causes several problems. Increased distortion (related to cone movement), and possible physical damage to the loudspeaker. Those are the 2 "biggies".


Now here comes the problem. If that intended range is below 20Hz, there is a limited number of processors/devices that can provide a high pass that low.


I prefer a 24dB butterworth filter for highpass-because it provides the flattest response down to the filter point.


If you don't have a device that can provide a below 20Hz highpass, then I suggest a 6dB slope. Yes you will lose output below 20hz, but as you get lower and lower, you will get more protection against low freq.


HOWEVER-and this is very important, just because a device has a high pass-does not mean that it is ACTUALLY DOING



Here is a link to a Pro Sound forum that show measured responses of various high pass filters. Not what you think would be happening

http://srforums.prosoundweb.com/index.php/t/62864/6883/
 

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Discussion Starter · #19 ·

Quote:
Originally Posted by Ivan Beaver /forum/post/19632228


EVERY LOUDSPEAKER should be operated with a high pass filter-especially if pushed anywhere near its limit.


When you operate below where the driver is "tuned" or the intended range of operation, it will "flop around" which causes several problems. Increased distortion (related to cone movement), and possible physical damage to the loudspeaker. Those are the 2 "biggies".


Now here comes the problem. If that intended range is below 20Hz, there is a limited number of processors/devices that can provide a high pass that low.


I prefer a 24dB butterworth filter for highpass-because it provides the flattest response down to the filter point.


If you don't have a device that can provide a below 20Hz highpass, then I suggest a 6dB slope. Yes you will lose output below 20hz, but as you get lower and lower, you will get more protection against low freq.


HOWEVER-and this is very important, just because a device has a high pass-does not mean that it is ACTUALLY DOING



Here is a link to a Pro Sound forum that show measured responses of various high pass filters. Not what you think would be happening

http://srforums.prosoundweb.com/index.php/t/62864/6883/

Ivan thanks for the very thorough answer.


Penn, I looked for the link to the spreadsheet and can not find it. Where did it originate or can you provide a link?
 

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Discussion Starter · #20 ·
It appears the simplest solution is a Velodyne SMS-1.

Does anyone have an opinion on this?
 
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