Altec horns coming!

[theophile]

bowtie,
Just a few questions.
Are you running digital sources into the DCX,or an anlogue rig?
This is my only reservation concerning the digital crossovers.
I don't use a digital source.I've got digital sources,but I use my turntable in preference.I have an aversion to A/D converters(in fairness to myself I don't hold onto my aversions as principles,if they prove to be without foundation they're gone).
Since it's obvious I don't have a bias against Behringer,how does the DCX compare against illustrious brands like BSS and XTA?
I'm aware that there is a growing movement which is all about modifying the DCX,but if I was going over to a digital active crossover I'd be prepared to pay for a superior sounding unit,should the DCX(with whatever mods are out there)prove to be the lesser choice.
Has anyone compared an all-out,tricked-up DCX against one of the other well-regarded competitors?
Should I start another thread on this topic?

 

[bowtie427ss]

Theo, consider that my overall positive experience with the DCX is still developing. I've read other's reports of the DCX being very slightly "edgey" on HF, thus far i cannot say that i hear any of that. But, consider that these probably aren't the most discriminating of ears at age 43. Combine that with the 802-8G's frequency response characteristics, and "slight" VHF anomalies become relatively moot point.

The only source i've used with the DCX thus far is the analog output from my CD/dvd(a unit who's sound i'm very familiar with on multiple systems) player. A good friend is going to loan me a couple of different DAC's for the sake of "tinkering" and i'm interested in spending some time with those, and have the Behringer SRC2496 on my short list as well.

I think the DCX's performance and validity can be summed up pretty well by this quote from Old Guy

The things the Behringer fixes are more audible than it's artifacts- most systems could be improved by it.

Taken from this thread
http://www.hostboard.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/3729/t/3302

This thread also presents better answers in the form of discussion than i can give you for those last couple questions.

FWIW, the posts from Steve Mac are also quite compelling.

As you'll see, that thread was inspired by a specific question that pointed immediately to one of the shortfalls of nearly all analog networks, and then ran off topic into this exact discussion.

A similar thread here on AK might wring out some additional experiences and worthwhile discussion, and IMO is a good idea.:yes:

Tricking out the DCX is something way down on my long list, but it's something that catches my eye whenever i see examples or discussion. Adding more internal memory would be at the top of my list of improvements.

 

[Zilch]

In the next few weeks i'm going to flip a few raw altec components to finance a DEQ2496 and ECM8000, then i'm going to be a measuring maniac.:yes:

Heh, heh.... :thmbsp:

*******

Sound guys also bash Behringer because they find it not roadworthy.... :stupid:

 

[spaceman]

Thanks Theo and Paul for your support. This had better work for you Spaceman, or we're all gonna be plenty, uhmm ..., disappointed. :

ROFLMAO, I'll try not to disappoint you guys. Actually, this is the 1st NEW piece of gear I've purchased in many years, so it felt kinda strange. Well, last night was a little rowdier than usual, as this area of town is pretty saturated with college kids, so umm, I didn't exactly sleep normally last night. Most of the paperwork was just several copies of the user's manual in several languages, so it wasn't too difficult to figure things out, & throw most of it back in the box. Actually, thing's are pretty intuitive, and reading the manual wasn't as necessary as I thought, just confirmed what I guessed on my own. After another cuppa joe, I'll have at it. :yes: I have to say, I'm pretty encouraged by all the interest in this little project, especially coming from guys with far more knowledge & experience than I have.

 

[Zilch]

I have to say, I'm pretty encouraged by all the interest in this little project, especially coming from guys with far more knowledge & experience than I have.

We have ulterior motives: You're about to become the AK expert on this, and thus, the vector for all future inquiries.

[It's plenty good fun too, of course.... :thmbsp: ]

 

[spaceman]

Mmkay, I'm all hooked up finally, & ready to fire it up. I think I need a refresher course in cable management, lol, at least on the tidying up end of things. I have the inputs to the Behringer coming from the pre-outs of the Concept receiver, HF outputs to the Concept's main-ins with wires running to the Altecs, and LF outputs into the main-ins of the Sansui, with wires to the EVs sitting on the floor for now. I've double-checked all the buttons on the back of the Behringer, for 2-way stereo operation, and set the crossover range at 1k2 Hz. on the front. Also made sure everything's grounded. :yes: Now the only thing I feel a little nervous about, is where to set the gain on the Behringer, as well as the input levels, as I'm not too crazy about overpowering the drivers the first time I turn it on, lol. I think the volume knob on the Concept will keep me in the safe zone, but I thought I'd ask about this, since I'm not in familiar territory here at all. Hopefully, this is just jitters, and this'll all look simple in a few minutes.

 

[Zilch]

Make sure the Xover Freq button is in the "X10" position, selecting the 440 - 9.3 kHz range.

If you want to be safe at the start, turn the the output and input controls on everyting, including your amps, all the way down, then turn everything on and start your source playing.

Bring your amps up to maybe 1/4 power. Know that the HF drivers are going to require WAY less power than the LF, a factor of 10, most likely.

The inputs and gains on the XO are attenuators, and they do not got to "off," so you should be hearing sound in the speakers.

Bring up the inputs to "0" for both left and right channels, then you have +/- 6 dB on the XO output gains to bring the highs and lows into balance. That'll probably mean advancing the lows with the highs remaining at -6 dB.... :thmbsp:

Again, Rule #1: Amps off first, on last.

 

[Zilch]

A configuration issue comes to mind, though it's not likely critical: If you're running the HF off the Concept, you won't be able to dial its own amp gain(s) down unless it has control(s) separate from the volume control to do that.

Thus, it may be more appropriate to run the HF drivers and horns off the external amp, so that you can set its volume (or gain) to an appropriately lower level to compensate for the significantly higher efficiency of the compression drivers.... :yes:

 

[bowtie427ss]

Bring your amps up to maybe 1/3 power. Know that the HF drivers are going to require WAY less power than the LF, a factor of 10, most likely.

He's using the amplifier sections of receivers and has no control of the in gains in that respect. It's likely that he may have to run the LF outgain boosted and the HF cut to get it balanced.

................ and yes, what Zilch has highlighted in bold subtitle is very important!

Zilch, what are your feelings about running a "safety" cap(of the correct value such that it's rolloff starts an octave or two below the intended crossover frequency) in series on the HF speaker line?

 

[Zilch]

Zilch, what are your feelings about running a "safety" cap(of the correct value such that it's rolloff starts an octave or two below the intended crossover frequency) in series on the HF speaker line?

Yes, a good idea, since the amps are not new. He certainly doesn't want DC going to the HF drivers. I don't use them, but even my newer Sonic Impact amp has some amount of DC on its output.

Would you advise Spaceman about that, please? I'm thinking 33uF is an appropriate value. Jantzen PE #027-944 looks like an appropriate choice, $8.45 each. 85-cent NPEs would likely work on an interim basis, no?

Even if he ends up with an external compensation filter, he'll still want those in place, most likely.... :yes:

 

[bowtie427ss]

Would you advise Spaceman about that, please?

I'm not in contact with him outside of this thread, i gathered the receiver info from his posts.

I'm thinking 33uF is an appropriate value. Jantzen PE #027-944 looks like an appropriate choice, $8.45 each. 85-cent NPEs would likely work on an interim basis, no?

Sounds good to me.:thmbsp:

I used 28mfd Solens simply because i had them on hand. I was just not comfortable without them inline because of the x10 button on my CX, and i use amplifiers with no turn on relay or protection, they don't thump on power up but i wanted the LF/DC protection anyway.

I still however have a small inner battle about putting a capcitor in line simply because one of the main goals/benefits of biamping is supposed to be the absence of ANY passive components in the amplifier/speaker path, which takes me back to a generalization of Old Guy's quote in that "it's benefits outweigh it's artifacts". I believe this will also be the case with a compensation circuit in this app and others as well, the benefits will outweigh the artifacts.:yes:

 

[spaceman]

Well, everything works as intended, and sounds pretty great, but I REALLY need to get those woofers into boxes. It looks like I'll be getting used to all these controls for a few days at least, but overall, I'm really happy with the results, and I'm positive things will improve. The only thing that's kinda missing, is the higher LF & lower mid area, but that's most likely because of the woofers being on the floor, which I already noted. I'll be playing around a little more tonight, as I listen, I'm sure, but it's pretty much there. Thanx again, Zilch, I owe you a favor, and I definitely appreciate all the other input, as I'm sure I'll be re-reading this thread to better digest all the good info. :thmbsp: I'll be missing for awhile, gotta listen to KZOKs replay of the top 102 songs, which started at noon. EDIT: Almost forgot to explain, I have the output levels for HF turned way down, & the LF most of the way up, on the Behringer, and the Concept has 4 tone controls in it's preamp, bass, low-mid, high mid, & treble, so I have a lot of adjustments possible.

 

[Zilch]

Well, everything works as intended, and sounds pretty great.... I'm sure I'll be re-reading this thread to better digest all the good info. :thmbsp:

COOL!!

Reread this page, especially. There's two more things here you may want to consider: Reconfiguration with the HF on the external amp, and protection capacitors in series with the compression drivers.... :yes:

[No magic smoke, huh? :scratch2: ]

 

[spaceman]

Well, I've changed back to using the ESS drivers (4 Ohms) for now, and that helps with the balancing quite a bit, but I think I need to do something different, as I'm still missing a lot of low midrange/ upper bass. I can definitely try using the external amp for HF (I'll just switch them around, to keep the Sansui on LF), not a big deal at all. Actually, I was thinking about running the XLR/RCA cables into a tape monitor on the external, rather than the main ins, to give me a volume pot, & more adjustment on tone. More like using the external as an integrated amp, rather than a straight power amp. I guess a few wrong turns are fine, as long as I can avoid that magic smoke. I'll definitely look into that protection cap too, very soon. :yes:

 

[Zilch]

Well, I've changed back to using the ESS drivers (4 Ohms) for now, and that helps with the balancing quite a bit, but I think I need to do something different, as I'm still missing a lot of low midrange/ upper bass.

If those drivers aren't in cabinets, either, you probably should give that issue some priority attention.... :yes:

Actually, I was thinking about running the XLR/RCA cables into a tape monitor on the external, rather than the main ins, to give me a volume pot, & more adjustment on tone. More like using the external as an integrated amp, rather than a straight power amp.

That's fine, of course, until somone inadvertently hits the "Tuner" button and sends full range signal to the compression drivers. That'd be all right, probably, once the protection caps are in place.

I haven't used a tone control in probably 25 years. I KNOW I haven't seen any for at least 10.... :

 

[theophile]

A problem/issue I've found with the Altecs and the Behringer is that the sheer amount of gain available from the combination of active preamp/active crossover and poweramps,plus the extreme sensitivity of the Altecs(compounded by the fact that the 806 is about 103dB sensitive when not padded down by a passive crossover),is that with the CX 3400's input gain controls set to 0dB,there is a lot of thermal noise.
This is duly a problem when the Kenwood 700C sounds much better when it's volume control range is left unattenuated(it's adjustable for -30dB and -15dB).
I also like to run my poweramps with their input attenuators fully open,so I compromised and I use the CX 3400 with it's left and right input gain/attenuate controls set at -12dB.
This arrangement only is viable with the analogue source.My television's output has to use the Kenwood's -30dB setting,and the output level of the DVD/SACD/DVD-A player has to utilise the -15dB setting.
In this system I applaud the wisdom of the 700C's designers for including this feature. :yes: :thmbsp:

 

[bowtie427ss]

Hopefully others won't take this as an opportunity for a flame war, but your(Theo's) situation is exactly why i use a behringer console for a preamplifier in my system.

One place Behringer receives a lot of accolades is for their "invisible preamps" used in several of the older "MX" series mixers. The use of a small console, while probably not cosmetically acceptable for many folks, gives me the flexibility to match the levels, and equalize if necessary, each input source ahead of the main/master gain controls.

My current setup has an inaudible noise floor. All three power amps are vintage pro amps with input gain controls set wide open. Speakers are A7-500's and a quad of 15" subs. With my CD/DVD stopped or paused i can run my mains sliders beyond unity and up into the "no no" zone and get zero audible noise. The best part is that i can acheive insane SPL's with incredible amounts of headroom left at each stage of the signal path.

The input gains, as well as all 6 out gains on the DCX ride at their neutral/zero position as well, i guess i lucked out a bit that my amplifiers' input sensitivties are well matched to the DCX.

Before the DCX, i used to run passive XO(with comp for 802-8G) on the A7's using CX2300 to biamp between the subs and A7's with ingains at neutral, and about 3db of gain on the LF and a db or so of cut on the HF, i always had "idle noise". The noise wasn't really at an objectionable level in my large listening room, but in a more intimate setting like my living room where i'm only 5 or 6 feet from my speakers, it would have approached unacceptable levels. There's no doubt in my mind that the CX2300 was the source of the noise.

Important also to note that i'm using all balanced signal lines, and my amplifiers are 20 feet or more away from the other upstream components as well as on their own isolated AC mains.

 

[spaceman]

Well, I swapped things around last night, and it definitely did the trick, the sound is SO much better now. Not only did I find my missing mids, but it seemed to make what I was already hearing before sound more matched and musical, at the same time, like we wanted all along. Just to verify it for anyone who might be confused, I'm using the Sansui 7000 receiver's tuner and preamp as the source (with all the inputs for tapes & TTs still available), the XLR/RCA cable from it's pre-outs to the Behringer's inputs, LF back to the Sansui's main-ins to power the woofers, and HF to the Concept's tape 1 inputs, to power the Altecs. :yes: Oh, in case you guys are wondering about power, the Sansui puts out 100 wpc @ 4 Ohms, and the Concept puts out 55 wpc @ 8 Ohms, so it's a pretty good match I think. It was getting into the wee hours when I finished, so I couldn't really give it much volume, but my system's in a pretty small room, so it doesn't TAKE much volume at all to fill it up. I believe that's it now, besides those protection caps. And better amps, lol, you're never done upgrading.

 

[Zilch]

Well, I've changed back to using the ESS drivers (4 Ohms) for now, and that helps with the balancing quite a bit, but I think I need to do something different, as I'm still missing a lot of low midrange/ upper bass.

Near the middle of the front panel of the CX3400 is a little button with the legend, "CD Horn." Push in that button to engage the CD compensation and then rebalance the highs vs. lows. That'll take the upper-midrange "Shout" out of the horns, flatten the response, extend the high frequencies, and allow your lower mids and upper bass to be evenly balanced with them.

High-frequency compensation is a major reason we advised doing this. It may not be the optimum curve for your particular Altec drivers, but I'm betting it will make a significant difference in the overall performance of your system.... :thmbsp:

 

[spaceman]

Sorry I didn't respond sooner, had a lot of chores to do today. Yep, I already had that CD (Constant Directivity) Horn button on, when I posted this morning, but thanx for reminding me. It definitely brings out the highs, like cymbals & some guitar work. :yes: I have a rough idea what the threshold limiter does, acts somewhat like a fuse, but have no idea where to set it yet, so just have it at 0 until I know better. :scratch2: I haven't really played with the low delay yet either, but don't see a need yet. I suspect that would be useful in larger rooms. Geeze, you guys are making me do an awful lot of thinking & learning, just to listen to music.