Digital EQ and Xover for OB - noob questions!

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mcgsxr

Digital EQ and Xover for OB - noob questions!
« on: 13 Feb 2007, 03:05 pm »
I see a number of folks are playing with this stuff, and Dmason brought it up many months ago, who can help me understand how to implement this stuff?

I use a computer front end with SB3.  I assume I take the digital output, into a digital EQ - does this also provide a sub out, or simply analog outs?

Trying to understand how to incorporate my sub plate amp, and my Magnavox SE el84 amp.

Thanks,

Rafal

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #1 on: 13 Feb 2007, 03:21 pm »
That's a very timely question. I'm in the same boat (alse using a sub). There is a unit that has a digital eq and crossover in one (I think it is called DBX Driverack PA) http://www.dbxpro.com/PA/PA.htm

It would be cool but it's about double the price of Berhringerd DEQ 2496. The other unit I was looking at was Alesis 230 but I'm not sure if it can do auto EQ (I would really like that feature because I don't want to spend months getting the sound right).

Right now I am leaning towards the Behrnger. Maybe the EQ can be used to implement a high pass filter and just EQ the mains.

 

JohninCR

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #2 on: 13 Feb 2007, 04:12 pm »
If you guys are using your computer as a source, why not go all the way and have it do the XO and EQ too?  I don't know what the SB3 does, I've never looked into it, but I've used my computer as a source for years.  I got tired to waiting for the Behringer's to be in stock, and went with a software solution, and I'm really glad I did.  All I needed was a multi-out soundcard, and now I have the ability to control up to 5-way, so even my subs are handled.  For about the same price as a Behringer, I got a complete solution that does more, and includes upgrades going forward.  You do need to be running XP, but your existing soundcard may already give you the ability to see what it's all about if your card uses ASIO drivers.  I'm not an affiliate yet, but I will be, so tell Jan at Thuneau that JohninCR sent you and maybe you can get some kind of deal, or maybe we could put together a group buy.  I sent Jan an email to see if we can get an AC discount.  Anyone using a computer and OBs will love this.  In the next couple of months measurement software will be available too giving you measurements directly into system, then all you'll need is a mic.

goo

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #3 on: 13 Feb 2007, 04:54 pm »
I Have both options. the folks at Thuneau are great. One major thing however, If you are running XP make sure it is not XP Media Center Addition. This is were I went wrong
Behringer Option:
I am quite happy with the set up right know The main reason I would switch is the options the PC XO  offers you (4way+Measurements). I am going to persue the Behringer option as far as possible to truly compare the two options. I just added the SRC2496 to the mix and had one of those eureka moments in Audio.
 aa

goo

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #4 on: 13 Feb 2007, 05:42 pm »
Oh way more important issue. IMHO The PC XO seems to be the cheaper option:
Here's how I'm set up.
Behringer Option:
Source: Toshiba Laptop PC or Modded IRiver SlimX or IRiver H120
All of these feed a SPIDF signal (optical) to the SRC2496. The signal is processed to provide AES/EBU out put to the DEQ2496 (EQ). The output than feeds the DCX2496(XO). From there I am splitting the signal three ways. The B200 is full range OB. From 150hz to 60Hz (very steep) I have a pair of Alpha 15a (thx MJK) on the same OB baffle. (this is not the best, however The Alphas are not being driven very loud). 60hz and below is being handled by a Decware WO32 (w/decware 10's). The amps are (in order) Two Charlize (SLA Ps) Modded Jolida 202a, and a Cyrus 2 .. oops Lunch is over, and we are about to get some serious Snow tonight...Weather report from CR :) ?
I have to get back to this later
q

JohninCR

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #5 on: 13 Feb 2007, 06:03 pm »
... serious Snow tonight...Weather report from CR :) ...

We're in full blown dry season now, and the chilly windy nights of January are gone, so think of a perfect spring day with highs in the upper 70's and just the right breeze to keep you nice and cool in the shade, and that's what I have every day until at least May.  Time to make my rig mobile and get it outside to the park adjacent to my house.  It's also time for a couple of days at the beach, where it's about 10deg warmer, but the ocean is cool. :D

Rafal

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #6 on: 13 Feb 2007, 06:05 pm »
I think I still preffer the hardware solution. The  DBX Driverack PA http://www.dbxpro.com/PA/PA.htm seems like the ticket. I saw it on ebay for less than $400. I just hope it won't mess up the signal too much. All that I would need on top of that is a mic and if I want to add a tweeter or bass Augmenter, than I already have an active XO for it. I could even run a sub and B200 highpassed around 80-100hz and then use a flea powered amp fot the drivers. This is what Dmason suggested in: http://www.diyaudio.com/forums/showthread.php?s=&postid=1134166#post1134166



ryno

Re: Digital EQ and Xover for OB - noob questions!
« Reply #7 on: 13 Feb 2007, 07:16 pm »
I've got the behringer DEQ2496, it has analog/digital in and analog/digital out. It works best using the digital, optical in/out. My DAC has switchable coax/optical, so I use this to switch the eq in/out. No xovers in this unit, just eq, parametric, graphic, and dynamic. The behringer DCX2496 has xover and eq, but doesn't have digital out. It forces you to use it's DAC's. I don't know the difference between this and the driverack from DBX but the DCX2496 is a bit cheaper.
Ryan

http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=248-669

Mark, how are you planning to do volume control? Might be tough if you are using the SB3.

ashok

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #8 on: 13 Feb 2007, 08:12 pm »
Hello everyone,

I have been looking at the Behringer DEQ1024 - a digital stereo equalizer with 31 bands. http://www.partsexpress.com/pe/showdetl.cfm?DID=7&PartNumber=248-742

At around half the cost of the DEQ2496, it sure seems attractive enough. It does not have a lot of the bells and whistles that the DEQ2496 has, but appears to allow equalization in the digital domain. Has AES/EBU and SPDIF in and out and also an analog in/out.

One thing that bothers me is that the specification sheet states that both the input and output impedance of the digital connection are 110 ohms. If I understand it correctly, the AES/EBU uses 110 ohms, while the SPDIF should use 75 ohms. Might be just an error of omission.

Has anybody tried this unit?

Regards,

Ashok

mcgsxr

Re: Digital EQ and Xover for OB - noob questions!
« Reply #9 on: 13 Feb 2007, 08:24 pm »
All interesting ideas.  I am still just using the SB3 as my only source, so volume will have to go through that.

I wonder what would happen, if you feed a variable signal (analog) into the EQ, I assume that would still work?

Just sniffing at ideas, not set on any direction at this point.  I know that plenty of folks are doing it, and they seem happy, so I thought a discussion around it would make some sense.

Who knows, perhaps some of us will be pushed over the edge!

goo

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #10 on: 13 Feb 2007, 11:01 pm »
Ryno nailed the weaknesses with the Behringer DCX. This same weakness could be with the PC XO also (however the signal is processed rather differently then most hardware approaches)...don't know yet, I'm in the middle of trying to quite a tower I will dedicate to the system
 I plan to do some major tweaks to the DCX's analog output. also the volume control is an issue which is why I am working on a new valve pre for the system. One thing that helped with the DCX was the addition of a Decware ZBox. Since adding the SRC I have removed the Zbox from the signal path. Couldn't stand the buzzing anylonger (I've got to do someting about that too..when it was quite it was fantastic)
have fun
q

ryno

Re: Digital EQ and Xover for OB - noob questions!
« Reply #11 on: 14 Feb 2007, 01:30 am »
Mark, the variable signal will work with all the behringers. If you have your full range signal go through one of these eq's, you're going A/D EQ D/A. Not the best with mine. If you just want to EQ the subs, a splitter, then through an EQ then the plate amps sounds like a great idea. No high pass on your mains, but EQ on the subs with out the A/D D/A on the mains. For this, the DEQ1024 sounds like a great idea.  Or the DCX2496 with EQ and low pass for more money if you don't have a xover in your sub amp.

Quote
One thing that bothers me is that the specification sheet states that both the input and output impedance of the digital connection are 110 ohms. If I understand it correctly, the AES/EBU uses 110 ohms, while the SPDIF should use 75 ohms. Might be just an error of omission.

This always comes up when you talk about behringer eq's. Some say it's not important, some give a link, cant find it now, for impedance connectors. If I remember right, they were $30 each, and you need one for each side of the EQ. This plus the RCA to XLR made me pick the DEQ2496.
Ryan

JohninCR

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Re: Digital EQ and Xover for OB - noob questions!
« Reply #12 on: 14 Feb 2007, 08:34 am »
Something to keep in mind is that CD's will soon be a thing of the past much like vinyl.  There are huge gains
in convenience and some gains in sonics by having your music library in your computer.  Sure there are intermediate
steps you can take with some new equipment items coming out that help people make the conversion, but they
are just glorified portions of a PC that will soon become obsolete.  Once you embrace the idea that music storage
should be centralized, then it's back to simplicity to get the best sound without damaging the signal before it
comes out of your speakers.

In my case, a digital copy of my music is on the hard drive.  When I start a song, the system makes multiple copies
of that digital signal and filters each at my direction.  This all occurs using a more powerful processor and more precise
processing than separate equipment items can have, or even if they're the latest and greatest today, they'll be behind
the times tomorrow.  Plus, since it's software driven, updates are simple without the need for new hardware.  This all
takes place in the digital domain, and I haven't detected any signal degradation with the algorithms used.

These multiple digital signals go to the soundcard for conversion to analog by the separate soundcard DAC's and direct
connection to my amps.  I see it as pure and clean digital signals going to multiple DAC's so each isn't working as hard
as they would with a full stereo signal.  There's only one clock controlling everthing to keep it all correct in relation to
time.  That leaves me with the pathway,  Digital signal - DAC - IC - Amp - Speaker wire - Driver.  It can't get more
simple.  If you still want to use disks (a mistake in my book because you're at the mercy of reading a disk on the fly,
with the associated problems of jitter, read errors, sampling, error averaging, etc.), just connect it to your souncard.
If you have analog sources, you can send them to the soundcard too, but you're at the mercy of the analog to digital
conversion, which might be a problem.

That's my 2 cents, but I'm not into changing equipment or cables.  I stick to changes in speakers and my room, where
the differences are often significant, but I know are real even if they are too small to hear.  I choose to leave the
magic to the musicians.