Concept of time delay?

[Guest " "]

"Behringer for $130"

Not the most transparent sounding piece on the market, but will work for a Cornwall type speaker, but not a LaScala or Klipschorn type speaker. Will not fix the tweeter. A DCX2496 can, they are back in production again.

 

I like this feature, good for folks who swap out xovers often.

"A PCMCIA slot allows you to store all your settings and recall them anytime you change the location"

[sfogg]

You don't even need the memory card, it has internal memory too. You can store 20 or 30 different setups in the crossover and change between them via the front panel or RS232.

Shawn

[bodcaw boy]

WOW!!! doc told me that this was a hot topic on the forum. time delay; does it matter? until you hear it, probably not......

[Guest " "]

It's pretty clear, that using passive crossovers, the fix's for the individual phenomena are difficult, and often have side effects on other issues (fix time issues by using higher order xovers, increase phase shifting/ minimize phase shifting by using lower order xovers, time shifting increases etc).

Any other audio phenomena to consider before deciding on a passive crossover upgrade/fix vs an active crossover solution?

[mikebse2a3]

WOW!!! doc told me that this was a hot topic on the forum. time delay; does it matter? until you hear it, probably not......

Roy I emailed you but thought I would just post my question as well.

OK Roy I've got to get busy on my crossover choices for the Jubilee. I sure don't want them just setting silent and waiting on me for crossovers.[]

http://www.behringer.com/DCX2496/index.cfm?lang=ENG

I believe you said this one would work good fo me?

It looks like it's available again and cost wise I believe it would make more since (Since I do want Time Correction) for me versus the (Cost of building the passive crossovers and using it in conjunction with the delay module from my DEQ2496 that I thought about using until I could find a suitable Active Unit).

Roy I would appreciate any of your thoughts on the different Brands/Models and Features Needed in the Behringer and Other Brands that I also should look at for the Jubilee.

Mike []TN

[jorjen]

The Rane AC24 looks pretty sweet.

[sfogg]

"Another reason I think slower slopes sound better is that the polar

response and distortion characteristics don't change as abrubtly

resulting in a speaker sounding like one unit and not two seperate

entities."

You have heard a speaker with sharp slopes sound this way or you are theorizing that this is how it would sound?

WRT polar response just match your horns dispersion and that isn't an issue. One should be doing that anyway no matter what slope they are using. The polar response in that case will be better with steeper slopes then without since you won't have as much off axis combing making the off axis response all helter skelter. In a real room as you know the off axis response contributes to what you hear on axis too.

As far as sounding like one entity or two the coherence I'm getting from the sharp slopes make it sound far more like a single driver then multiple drivers to me since you sharply limit the interference effects of the drivers.

At the levels most people listen at in a home the THD and THD+N should be pretty low anyway so no big changes moving from one driver to the next. When I measured THD+N on my setup it was around 1% above and below the crossover point at around 90dB at the listening position. And that was including the entire chain of soundcard-> Lexicon (A/D->DSP (subwoofer crossovers + sub time alignment)->D/A), DCX2496 (A/D->DSP (triamp crossovers/EQ/time alignment)->D/A, amps, speakers, mic pre-amp, and finally back to the sound card.

Shawn

[sfogg]

Mike,

The biggest thing to watch out for on the DCX2496 are the input/output levels. It needs higher then normal levels for consumer gear. Fullydriving the input/ouputs is key for full resolution of the A/D and D/A in the unit. I detailed that more on the thread about setting up the tri-amping on my speakers.

Shawn

[DrWho]

"Another reason I think slower slopes sound better is that the polar

response and distortion characteristics don't change as abrubtly

resulting in a speaker sounding like one unit and not two seperate

entities."

You have heard a speaker with sharp slopes sound this way or you are theorizing that this is how it would sound?

WRT

polar response just match your horns dispersion and that isn't an

issue. One should be doing that anyway no matter what slope they are

using. The polar response in that case will be better with steeper

slopes then without since you won't have as much off axis combing

making the off axis response all helter skelter. In a real room as you

know the off axis response contributes to what you hear on axis

too.

Yep, speaking from personal experience...

Btw, every horn from klipsch and most other products on the market

implement a narrowing dispersion for the high frequencies to increase

on-axis sensitivity and extend the bandwidth of each component. The

point being that it is rarely the case that polars will be matched. The

upperband of the lower driver is almost always narrower than the

lowerband of the higher driver...unless you go for an extra narrow polar

at the highest frequencies - which of course has its own sonic attributes.

And as low as you claim the distortion for any speaker is - the

distortion is what is responsible for the signature sound of that

driver - and as far as I know no two dissimilar drivers are going to

have the same distortion patterns.

[sfogg]

"Btw, every horn from klipsch and most other products on the market implement a narrowing dispersion for the high frequencies to increase on-axis sensitivity and extend the bandwidth of each component. The point being that it is rarely the case that polars will be matched."

Your point was polar response changing dramatically at the crossover point if one was using sharp filter. So that something like a K400 or 511Bs dispersion getting narrower on the top end isn't relevant to what happens at 400hz.

The narrowing dispersion of non-CD horns happens no matter what crossover slope is used.

"the distortion is what is responsible for the signature sound of that driver -"

That is part of it but certainly not all of it.

As far as changes in distortion patterns happening sharply that really would not be the case as you would have a region of overlap just due to the nature of harmonic distortion anyway.

Think about it... if one crossed at 500hz 100,000,000 dB/octave if you feed the woofer a 400hz tone and test for harmonic distortion will you see any?

Of course you would.

The crossovers filter what is fed to the driver. It doesn't filter what the driver does from that point on. If the driver has a second order harmonic it is going to be showing up at 800hz (at the same amount) no matter what crossover slope you use.

Shawn

[DrWho]

Your point was polar response changing dramatically

at the crossover point if one was using sharp filter. So that something

like a K400 or 511Bs dispersion getting narrower on the top end isn't

relevant to what happens at 400hz.

I'm talking about the horn going below the squaker - like the khorn

bass bin or the lascala bass bin. And if you're crossing at 400Hz, the

K400 or 511B is nowhere near big enough to maintain pattern control

that low (meaning it's closer to omnidirectional).

"the distortion is what is responsible for the signature sound of that driver -"

That is part of it but certainly not all of it.

I thought distortion by definition is any sound not intended. If the

driver has a signature sound, then the things causing that signature

must be distortion?

Think about it... if one crossed at 500hz

100,000,000 dB/octave if you feed the woofer a 400hz tone and test for

harmonic distortion will you see any?

Of course you would.

The

crossovers filter what is fed to the driver. It doesn't filter what the

driver does from that point on. If the driver has a second order

harmonic it is going to be showing up at 800hz (at the same amount) no

matter what crossover slope you use.

First of all, THD is only one of many distortions and according to a

lot of research is one of the least audible. And looking just at the

THD versus the individual harmonic distortions isn't going to tell us

very much. How bout something like IMD? One of the aspects horn lovers

love to tout for the superiority of horns. It's a distortion shown to

be very audible and is a direct function of the passband / mechanical

efficiency of the driver. Right around the crossover region you'll be

going from a very doppler shifted signal to one with none.

And yet another factor is the impulse response...I can't imagine there

being any general rules of thumb as different drivers are optomized for

different regions of their passband, but I definetly wouldn't assume

the impulse and square wave behavior is going to be identical on both

sides of the crossover point. The bottom driver is going to require

less cone-movement for the same SPL, but is going to have a greater

mass. I suppose an argument could be made for trying to minimize

overlap to reduce smearing of the impulse, but I'd need to spend more

time playing to come to my own conclusions.

I'm not trying to make a blanket statement for against specific

crossover slopes, but just mentioning some of the compromises invovled.

And I'm sure I'm not even aware of all them either. Nevertheless, I can

confidently claim brickwall crossover slopes are certainly not the

ideal. There will be a happy medium somewhere in the middle depending on the actual components involved.

[mikebse2a3]

Mike,

The biggest thing to watch out for on the DCX2496 are the input/output levels. It needs higher then normal levels for consumer gear. Fullydriving the input/ouputs is key for full resolution of the A/D and D/A in the unit. I detailed that more on the thread about setting up the tri-amping on my speakers.

Shawn

Thanks Shawn!

I noticed another thread has been started on the Behringer so I'll be watching for your's and others comments there.

mike[]

[djk]

"But, by adding elements wouldn't one compromise the beauty of a clean sounding zero feedback pre-amp and SET or PP amp with the addition of many small resistors and op-amps?"

It's amazing that anything sounds as good as it does considering the literally thousands of small resistors and hundreds of opamps in the recording chain. The biggest offender is the electrolytic coupling cap. If you look at just a single channel strip on a mixing console you won't believe how many there are, not to mention in the side chain.

The DCX2496 has 17 very inexpensive opamps and 15 very inexpensive electrolytics in its signal path.

All the opamps and capacitors in the signal path may be replaced with transformers for a cost of about $80. The ADC will get its DC off-set through the centertap on the input transformer, and the balanced voltage output DAC will perform the lowpass filter and DC removal with another transformer. The transformers will also eliminate any ground loops.

http://f2.grp.yahoofs.com/v1/8G6nRLR-TJGM4fKWVPoBJ2U4nT0LvT1OJvQ-QJXgn22T0Y4cs6-iPPztZk-u0omVbK1m-wtyvtyaX3G6INYespwRIGqaJZzw/DCX2496-REAR-REVE.pdf

[rigma]

"And thanks Rick, that orchestra allusion really makes us toss all the time-alignment theories out the window, doen'st it? Is it possible that the brain adjusts for the differences, then ignores them? That would be one thing Doc could not measure. "

That was my point Micheal. The brain is a wonderful thing. A sewage plant stinks to most of us, but a person who works in that plant does not notice the odor.

Sometimes, we get ourselves in trouble or cause more trouble for ourselves attempting to find "prefection" Perfection to mere mortals like us is unobtainable.

DJK, who's knowledge and experience I respect greatly, may well be correct, hearing a time corrected Khorn may be a relevation. But, by adding elements wouldn't one compromise the beauty of a clean sounding zero feedback pre-amp and SET or PP amp with the addition of many small resistors and op-amps?

Like the good Dr's motto, life and audio is a game of compromises.

Rick

Great point Rick, I had my Khorns Tri-Amped for several years with a $4,500 Crown digital crossover with time delay. I sounded very good but it has since been replaced with zero feedback pre-amp and SET. At least with the music I listen to (Jazz LPs) the tone is now right..IMHO.. I have no plans to go back! I think it is a result to simplifying the signal path and eliminating SS and digital components.

Rigma

[Guest " "]

"But, by adding elements wouldn't one compromise the beauty of a clean sounding zero feedback pre-amp and SET or PP amp with the addition of many small resistors and op-amps?"

It's amazing that anything sounds as good as it does considering the literally thousands of small resistors and hundreds of opamps in the recording chain. The biggest offender is the electrolytic coupling cap. If you look at just a single channel strip on a mixing console you won't believe how many there are, not to mention in the side chain.

The DCX2496 has 17 very inexpensive opamps and 15 very inexpensive electrolytics in its signal path.

All the opamps and capacitors in the signal path may be replaced with transformers for a cost of about $80. The ADC will get its DC off-set through the centertap on the input transformer, and the balanced voltage output DAC will perform the lowpass filter and DC removal with another transformer. The transformers will also eliminate any ground loops.

http://f2.grp.yahoofs.com/v1/8G6nRLR-TJGM4fKWVPoBJ2U4nT0LvT1OJvQ-QJXgn22T0Y4cs6-iPPztZk-u0omVbK1m-wtyvtyaX3G6INYespwRIGqaJZzw/DCX2496-REAR-REVE.pdf

I wanted to follow up on your last para. I clicked the link and got a file not found error. if you have the dcx2496-rear-reve.pdf, can you post?

thanks.

[Guest " "]

The Rane AC24 looks pretty sweet.

very rare to find an active xover that can do stereo 4 way in one box.

other models require 2 boxes to do 4 way.

cost wise, intially looks high, but if you compare to 2 3-way boxes, the cost is just slightly higher.

does anyone know of an active xover that is THX certified?

[djk]

http://groups.yahoo.com/group/DCX2496/files/

Then click on:

DCX2496-REAR-REVE.pdf

[Guest " "]

http://groups.yahoo.com/group/DCX2496/files/

Then click on:

DCX2496-REAR-REVE.pdf

fyi, This link requires a yahoo login id.

[sunnysal]

hey dennis is anyone doing these upgrades for hire? looks and sounds like these mods can really turn a "good for the money" unit into a "wow" unit for modest investment. thanks, tony