Query on Time Delay for Electronic XO

[ngccglp]

Hi,

I did some research and noticed that most Elect XOs (Rane, Behringer) only allow for time delay adjustment for low output only i.e. case where horn diaphragm is behind the woofer.

When adding tweeter to A7, it is likely that the tweeter will be in front of the woofer. In this case, is there anyway to compensate for the time delay for the tweeter? Or is it that for high freq the time delay is negligible?

Thanks

[StuWelwood]

You could use a Rane AD 22D (see http://rane.com/ad22d.html) or the really cool, very capable, and less expensive RPM 2 Programmable Multiprocessor:
http://rane.com/rpm2do.html

[bfish]

Originally posted by ngccglp:
...Or is it that for high freq the time delay is negligible?

<font size="2" face="Verdana, Helvetica, sans-serif">Actually, it's just the opposite.

Say your mid/high XO was at 7kHz, and you had an 18" VC offset. at 7kHz, the wavelength is roughly only 2 inches, so the phase offset is roughly 9 complete cycles. Since phase offset is normally considered in fractions of a quarter of one complete cycle, you can see what a big deal that really is.

[ngccglp]

Thanks guys,

I will try to align the VC. But there's many pix in the horn webpage where the tweeter is placed right in front of the horn month. Wonder how those guys do it. Probably with an external delay.

[Old Guy]

To play a broken record...

Behringer DCX 2496 (click) Behringer DCX 2496 (click) DCX 2496....
Quote the propaganda sheet:

Start with its 3 analog inputs (one suitable as a digital stereo AES/EBU input) and 6 analog outputs. You get maximum flexibility in just one rack space. Superb high-end AKM? 24-bit/96 kHz A/D and D/A converters give you ultimate signal integrity and an extreme dynamic range of 113 dB. Easy connection of external digital signals with sampling rates from 32 to 96 kHz is a breeze with the integrated sample rate converter. There are precise dynamic EQs for level-dependent equalization and extremely musical parametric EQs, selectable for all inputs and outputs, and ?Zero?-attack limiters on all output channels guarantee optimal signal and loudspeaker protection.

You also get four different mono and stereo output operating modes, all with individual crossover filter types (Butterworth, Bessel and Linkwitz-Riley) with selectable roll-off characteristics from 6 to 48 dB/octave. The delays for all inputs and outputs are adjustable. This allows you to manually or automatically correct for room temperature, phase and arrival time differences. An additional sum signal is easily derived from the A/B/C inputs.

Now that remote control is such a hot topic, you?ll be glad that the future-proof ULTRADRIVE PRO software enables single or multi remote control via PC through RS-232 and RS-485 interfaces. And the link option via RS-485 network interface enables cascading of several ULTRADRIVE PROs. A Windows?-based editing software is available for download free of charge. No matter what the future brings, its open architecture assures easy software updates. A PCMCIA slot allows you to store all your settings and recall them anytime

End quote.

$339 list, heavily discounted. saw one on FleaBay for $200 a few weeks back.

I dare anyone here to show me a better unit for even triple that.

My only qualm- the in/out 3 pin balanced connections are soldered to the PC board. Road warriors replace them with panel mounts and run wires down to the board. not necessary for permanent installs.

[donaldpatten]

Hi
I suggest you line up the horn driver and the tweeter in the same plane. Or as you thought, get a delay for the tweeters.
Don

[ngccglp]

I hear you Old Guy

Is there a sonic difference between analog and digital XO? I have the impression that analog XO are better.

[Old Guy]

I repeat- I dare anyone to show me a better unit for triple.

There are some Euro guys who have mods for the in/outs to make them more home audio friendly. I'm not convinced they are needed.

As far as analog being better than digital-

Digital photography has relegated film to a craft type project. Digital photo can record more detail more accurately. The same will eventually happen in audio, in fact already has except the good gear has not gotten cheap yet.

There are numbers of tube diehards who rave about some of the European amps- Philips new digital amp circuits are hot stuff. They are ahead of Tripath- and lots of people think TriPath is pretty hot.

Some people like analog simply because it isn't accurate. All speakers and amps color the sound.

Someone who is used to JBL might like JBL coloration better than Altec.

Somebody used to nothing but analog might hate digital.

Personally- digital is already to the point where I would ignore anyone saying analog is better. As far as I'm concerned, they are simply stating they think their taste is best. They are welcome to think so. I refuse to acknowledge anyone Else taste as best.

I just said in another thread a few days ago, once you reach a certain level of quality it is simply opinion.

The DCX reaches that level.

Anybody who says analog crossovers are better hasn't played with Lake stuff.

Sorry so long winded. I just feel I had to qualify my answer. And I have no argument with different tastes- I even listen to them. If I don't like them I won't acknowledge them as better though.

[klausesser]

Hi old guy!

"Digital photo can record more detail more accurately."

Theoretically: yes. Practically: no, depends.

As it is in audio, you have to look closer to the details.

A large-format - lets say 4x5" or 8x10" - photograph which is scanned on a drum-scanner shows much more details than a digital photograph which was shot using a 50000.-$ digital back.

As you can?t really reproduce low freqs. with a small speaker, you can?t record fine details with a limited medium. And digital IS a limited medium - because of relative small chips with relative many pixels. I?m talking of photography at average costs . . . (if you?re willing to spend some 50000.-$ for a digital scan-back and if you don?t have a problem with exposure-times of several minutes: you may come close to 4x5" negatives - but still not 8x10" negatives or transparencies you can use equipment of under 5000.-$ for).

A pixel has to have a certain dimension. Otherwise it?s ability to collect light is very low. To get a usual sensitivity you have to rise electrical gain. That produces noise. Noise has to be reduced electronically by software and that causes a loose of details . . . and so on.

Digital photography is very limited. When you take a close look. As an example: you?d need 22MPx to print a photograph in a two-page magazine ad. That?s in reach of top-level cameras. But as a photographer you have to think about the editor?s ability to make crops. So you?d better shoot with about 33MPx.
A scan from a let?s say 6x9cm film-negative you can get about 100MPx from - not loosing details!

Digital audio is a far more developed - it started earlier.
But remember the early times in digital audio . . . gosh . . ;-) - in a comparable situation we are in digital photography at the moment.
I?m sure it will overcome analogue - some days . .

The only really advantage: it?s more simple to handle.

I often use digital photography - but when it comes to the "good jobs", the "fine ones", i shoot analogue, have my selected shots drumscanned and overwork them digitally (i?m an advertising photographer and often do people-shots but also stillifes and product-shots in a bit sophisticated way).

My saying: digital photography to me is like Bang&Olufsen in audio - analogue photography to me is more like Altec . . . javascript: x()

best, Klaus

[bowtie427ss]

I'm not a photography expert, but i know where my money is best spent for an active crossover solution.

Sorry i don't have a pic of one of the delay pages up here, maybe i can edit one in tomorrow.