Balanced connections question #342

[sfogg]

Coytee,

If it were me I'd use the RCA to XLR from the Peach to the EV. Then just a balanced from the EV to the amp. If the Peach can put out 45v it should have no problem whatsoever driving the EV crossover.

Additionally... the EV crossover is a digital crossover. You should try and maximize levels into and out of the crossover to maximize SNR/resolution through the crossover. This can be a little tricky. What you basically want to try and do is set your levels up such that at whatever you max SPL you listen at is within a couple of dB of full scale on the A/D and D/As in the crossover. I haven't used the EV but with the Behringers to do this required a 'hot' signal into the Behringer which resulted in a hot signal out of it and then added attenuation in the amps to get my levels where I wanted them. This keeps SNR/Resolution through the crossover maximized. I detailed this a little more in this thread:

http://forums.klipsch.com/forums/thread/613138.aspx

Shawn

[DrWho]

No offense intended here but why are you using a computerized PA crossover for home audio? Why wouldn't you use a nice audiophile grade crossover with those fantasitic speakers?

Just curious - have you used or heard the Dx38?

Does the XM26 offer signal-alignment? Without such a feature I think it would make more sense to go with passive crossovers.

[sfogg]

Mark,

"Something like this http://www.marchandelec.com/xm26.html is about $1500 or so and will smoke that digital thing you are using now for sound quality."

Don't count on it. The XM26 *would not work* for a Jubilee alone. The HF horn/driver requires EQ because the upper horn is a form of CD horn. The XM26 doesn't offer that. As such the system would be very dark with the XM26... that won't sound better.

Likewise it doesn't offer the ability to time align the drivers. And it offers no other EQ which can be used to tune the system further to get a better end result.

"This noise CAN NOT be removed with "balanced connections" or transformers of any kind or configuration whatsoever."

The idle noise could be worked around though too. If it really can drive 45v (and I don't doubt you on this) putting 10dB of attenuation on the output of the Peach would drop the idle noise 10dB (huge amount) and the Peach would still have plenty of gain to work through that.

Totally agree with you that something isn't correct about Coytee having to turn up the Peachs volume all the way.

Shawn

[Coytee]

Coytee,

If it were me I'd use the RCA to XLR from the Peach to the EV. Then just a balanced from the EV to the amp. If the Peach can put out 45v it should have no problem whatsoever driving the EV crossover.

That is basically what I've got going today with the transformer OUT of the circuit. RCA/XLR from the Peach into the EV and XLR/RCA into my solid state amp and XLR/XLR into the McIntosh. Sounds very good but when I want to really put the pedal to the metal, I can still be in the room with the Peach REALLY turned up and with ~550 wpc available per side (adding both amps together) I'd expect being in the room while standing on the throttle is NOT somewhere that would be easy to be.

Additionally... the EV crossover is a digital crossover. You should try and maximize levels into and out of the crossover to maximize SNR/resolution through the crossover. This can be a little tricky.

You are dead on here. During typical listening, the input lights don't light up at all. Just last night when I was 'cranking' it, I only had 2 maybe 3 of the LED's lit. When I had the transformer in the system, it was easy getting the input indicators to light up. Question for you and I'll use an analogy... in a car engine, it has a range in its powerband where its the most 'comfortable' being driven. You are not over driving it, nor are you lugging it and as such the engine can be the most responsive. I've wondered if the EV unit has an "input level" that it's comfortable with such that it's not being over driven nor underpowered. I don't know if that analogy makes sense or is a parallel one. It's just what came to mind.

What you basically want to try and do is set your levels up such that at whatever you max SPL you listen at is within a couple of dB of full scale on the A/D and D/As in the crossover. I haven't used the EV but with the Behringers to do this required a 'hot' signal into the Behringer which resulted in a hot signal out of it and then added attenuation in the amps to get my levels where I wanted them. This keeps SNR/Resolution through the crossover maximized. I detailed this a little more in this thread:

http://forums.klipsch.com/forums/thread/613138.aspx

Shawn

[Coytee]

No offense intended here but why are you using a computerized PA crossover for home audio? Why wouldn't you use a nice audiophile grade crossover with those fantasitic speakers? You had some beautiful amps for a while (maybe they are gone now?), and the Peach and all you needed was a nice AUDIOPHILE GRADE crossover and you should be making beautiful music with none of this craziness. Something like this http://www.marchandelec.com/xm26.html is about $1500 or so and will smoke that digital thing you are using now for sound quality. And, it's of course RCA connections. I'd bet anything that the Peach+Marchand+SEOTL amps+Jubilee will make superb music.

Part II. getting "6dB" is just more gain. You don't need a transformer in line to get "6dB more gain" - you need to simply turn up the volume control. I have to wonder if you don't have some weird setting (accidentally) plugged into that crossover which is grossly attenuating the preamp output? Lord, the Peach will drive 10 McIntosh amplifers to full power - I don't care what kind of Macs they are.

Of course, I am unsure of your goals, but based on what I know I think you are using the wrong tools.

Mark, the reason I'm using the Dx unit is primarily because it's the one Roy/Klipsch use. I knew nothing about these things and if I used the same one Roy used, I knew I'd be able to ask him about a question regarding its use.

The SE-OTL amps are now gone (presuming those are the ones you refer to as the beautiful amps). They WERE the most delightful sounding amps I think I ever heard on my Khorns however, they only had 4 wpc when bridged. Here I am crying like a baby only getting 10 watts into my HF horn and those only had 4 total... I don't know how many my bass horn is using. The OTL's simply did not have enough power for me although for within their range, they were probably the nicest sounding amps I've ever heard. I sold them PRIOR to getting the Jubilees. Had I not done that, I'd be trying them in the system to see if they'd take care of my lower listening level desires. Given that they're gone (prior to me even thinking on buying the Jubes), I HAVE thought about purchasing a pair of them again. I emailed Rozenblit and he suggested I might look at their bigger brother. I've debated on getting both sets so I could try them side by side. If I did that, I'd be buying 2 OTL's so I could bridge them and probably a single OTL 16 or what ever his number is for the next one up.

Part II I can turn the volume knob up to get 6 db more gain...until I run out of volume knob!! [] Let me ask a question... is it reasonable that if I in fact had something wired weird, I'd be getting 'funky' sound, rather than simply less volume?

Meaning, I once had a RCA/XLR cord soldered wrong on one of the ends. I had a hum. I found that wire, fixed the incorrect solder and hum went away. Remember... I've now had 11 forum members over (and one forum member wife) to listen to these. NO one has found any 'funky' sound. Interestingly, no one has really gotten into cranking them as loud as I might, except for Dale who came pretty close!! Surely with 11 forum members over, if there was something funky sounding (there isn't) they would have noticed it?

It might be the wrong tool... might be my ignorance, which I think is more likely.

[sfogg]

Coytee,

"During typical listening, the input lights don't light up at all. Just last night when I was 'cranking' it, I only had 2 maybe 3 of the LED's lit."

That is a problem. How are your RCA/XLR cables wired? Did you make them or buy them? I wonder if you maybe have a little bit of a short in them and you are dumping a lot of signal to ground. There should not be that much of a difference between XLR and RCA. Or bought something with attenuation built in?

"Question for you and I'll use an analogy... in a car engine, it has a range in its powerband where its the most 'comfortable' being driven. You are not over driving it, nor are you lugging it and as such the engine can be the most responsive. I've wondered if the EV unit has an "input level" that it's comfortable with such that it's not being over driven nor underpowered. "

That analogy doesn't really work as when you are cruising you are at a constant speed. With music even if you don't touch the volume control the level varies.... it isn't constant.

As far as levels in and out of the crossover go you want the loudest you ever listen to be within a couple of dB of overload/clipping on the crossover. Likewise at that same volume into the crossover you want its outputs to be within a couple of dB of overload/clipping on the output of the crossover. That will maximize SNR/resolution through the crossover for best sound quality.

When you don't have a reference for how loud you listen this will be harder to setup.

First I setup the system such that all drivers were balanced in level (using the output levels of the crossover) and working without worrying about levels in/out of the crossover. I looked at the relative dB differences between drivers based on the output levels in the crossover. Those became my target for later.

Next I went to maximize SNR through the crossover. In my case I had it a little easier as I have a calibrated volume control on my pre-amp so I sort of worked backwards from there. The loudest I listen is with the volume set at 0dB. Normally that would equate to 105dB per speaker at the listening position. So I set my pre-amps volume to 0dB and then played full scale pink noise (amps off) through the pre-amp and into the crossover. I adjusted the INPUT levels on the crossover so they were a few dB below clipping. Then with the crossover settings in place I adjusted the output levels of the EQ so each output was about 6dB from overload/clipping to give me a little wiggle room if needed later on. This throws off the relative levels between drivers. The next step corrects this.

From here I compared the new output levels in the crossover between drivers against the earlier driver settings. If say the mid was now 3dB closer to the woofer I made a note that I would need 3dB less attenuation in the mids amps 'correction' attenuation to get the relative levels of the drivers proper again.

I put the 'correction attenuation' on the amps as needed. This got the drivers back in relative balance. If I couldn't get it perfect (only a dB or two off) I used the output level controls on the crossover to really dial in the drivers the rest of the way. I would aim slightly lower and turn it up slightly in that drivers output control. Not done yet though.

Lastly.... with the pre-amps volume still at 0dB (loudest I listen) I played pink noise recorded at -20dB. Under normal circumstances this should play at 85dB per speaker at the listening position. Due to the levels in the Behringer this was still much louder then this. However much hotter this was (say SPL was 97dB per speaker.... 12dB hotter then it should be) I added 12dB more attenuation to all the amps in addition to whatever attenuation each channel had for channel balance. This re-calibrated the volume control and maximized resolution in/out of the crossover.

Obviously this was an iterative processes. It took several days to be able to dial this in. When I was doing it I only worked on a single speaker and after I got it I transfered the settings for the other two speakers and for the 9 channels of amplification. I also took advantage of my spectrum analyzer to do some of the balancing/testing electrically instead of acoustically.

Shawn

[sfogg]

One last point.... obviously after you get all this said and done.... if you change amps you most likely have to start over from scratch as different amps will have different gain and input sensitivities which will throw your settings out of wack.

Decide what amps you want to run with and stick with them. It is too much work to change amps around often when you bi/tri-amp and maximize levels through the crossover.

Shawn

[sfogg]

Mark,

"You are basically building a PA system using constant directivity horns and massive 300W amplifiers and digital processors."

These are not your typical CD horns. They are Tractrix flares (not exponential like almost all other CDs) with a CD like response to them.

Constant coverage in a home is useful as it helps make the speakers more consistent sounding room to room as the off axis response of the speaker is very similar to the on axis response. It also increases the size of the sweet spot.

There are many home audio speaker manufacturers (including some high end ones) which seek to have smooth off axis response because of how that sounds... even on axis.

Shawn

[DrWho]

But Shawn, that logic uses science and we all know that isn't audiophile...

It would be pointless for me to list all the "PA equipment" being used in the most high-end of systems, even on this very forum (*cough* altec *cough*). Mark is making comments about things he has no experience with - ya know, one of them audiophile traits that makes this hobby much more enjoyable. I might as well start giving Richard tube amp advice...[^o)]

[Coytee]

Part III. Noise.

Yes, there is a slight amount of tube noise inherent in the Peach or any other tube preamp. Please note: This noise CAN NOT be removed with "balanced connections" or transformers of any kind or configuration whatsoever. This slight idle noise is only an issue because of the speaker efficiency. When music is playing, the S/N RATIO takes over and the Peach is very good - about 80dB relative to 2V out. The oddity here is that you have to turn the levels up so high - this is very UNUSUAL and again, I have to suspect your crossover is "swallowing" all the gain. If you had a normal audiophile crossover, you'd be turning the Peach up to 10:00 o'clock and the walls would be collapsing from the loudness if you are using 100W amplifiers they will be pegged.

Again, no offense is meant here at all, but I think you've wandered so far off track by mixing PA equipment into a home stereo that you may never get it sorted out. Bi amping speakers is not hard to get exquisite results. I have built many bi-amped systems including big Altecs similar to your Jubilee. Preamp, proper crossover, couple tasty power amps, a few decent cables and bingo, you're done. And, it's all RCA one end to the other.

I'm not taking any offense to anything you've said here or prior. In fact I'm more fearing that maybe I'm doing a poor job of describing my situation.

This XLR stuff is 100% new to me as of several months ago and I'm meandering my way through it.

I DO have great sound from the Jubilees. They WILL play loud, clean, clear and with punch.

[Coytee]

Constant coverage in a home is useful as it helps make the speakers more consistent sounding room to room as the off axis response of the speaker is very similar to the on axis response. It also increases the size of the sweet spot.

Shawn, you are absolutely right here. The Jubilees are far far FAR better behaved in the room than the Khorns were. I've got a much better sweet spot, the 90hz node I had (with Khorns) is either not there, or more likely, simply not as noticable (ie, better behaved??)

I'd not be bashful to recommend the Jubilees to anyone who owns Khorns across the board, based on the improvement I've heard in this room. I'll bet no one has figured that out yet huh?!!

[]

[sfogg]

"It would be pointless for me to list all the "PA equipment" being used
in the most high-end of systems, even on this very forum (*cough* altec
*cough*)."

Forget Altec... how about *cough* KLIPSCH *cough*. LaScala's started life as PA speakers, Heresies were sold to Churchs, the K'Horn was used with Leslie organs, etc...etc....

Shawn

[DrWho]

hey Richard,

I remember reading the other day about Mike Beasly (sp?) helping you with your khorns a while ago and dropping in some EQ on some Behringer thing to tame a room mode. Are you still using that in your system?

[Coytee]

That is a problem. How are your RCA/XLR cables wired? Did you make them or buy them?

I wired them myself but had the diagram from the EV book. At the risk of VERY faulty memory, I think the black wire was my RCA center pin and the other two wires (white & sheath) were both grounded. On the other end, each wire went to each post and the sheath went to the ground post.

I wonder if you maybe have a little bit of a short in them and you are dumping a lot of signal to ground. There should not be that much of a difference between XLR and RCA.

I have tested each & every solder joint with the mate for it on the other end with an Ohm meter. Question... if I had a SINGLE strand cross soldered, would I not show TWO connections reading positive?

Meaning, what I did was put probe on one tip and on opposite end, put the other probe on EACH tip to make sure only ONE tip responded. If I had a second tip respond to the probe, I knew I had them touching somewhere. Although that probably did happen to me, I think it only happened maybe once. I tested EACH wire inside the cable this way and I'm 99.99999999999% positive that each wire is soldered with no grounds to another post. (one can never be 100%!!)

Or bought something with attenuation built in?

Nope

When you don't have a reference for how loud you listen this will be harder to setup.

Perhaps that's a side issue for me as when I'm in the room, I am usually under 1 watt as measured on the McIntosh meters and only sometimes pushing 5 or 10 watts (on the 2102 meter).

However, when I'm outside, downstairs or in another part of the house, I am NOT afraid to let it RIP so I can hear it while I'm out of the room. We're talking ear blistering if in same room. As such, I do not have a typical listening level that some here might consider typical?

[Coytee]

Mike,

You are right in that Mike did bring his Behringer over. It was the Behringer that he used to discover (verify) the mode and get a feel for how big/dramatic it was. By happenstance, it was right at 90 hz. I do not recall how tall (?) or strong it was. He knocked the 90hz down and the room sounded a lot better right off the bat.

As luck/happenstance would have it, I had a dbx 14/10 eq in the closet. I pulled it out and slapped it into the tape loop of the Peach and the eq happened to also have a slider at 90 hz. I knocked it down several db's and all was well.

With that explained to you and before anyone else jumps in on something else being in the food chain, I might add... today with the Jubilees in there, the muddiness that we heard at 90hz is greatly reduced by having the Jubilees in there (as far as the ear is concerned). Because of that I typically do NOT listen to anything with the dbx unit in the circuit. Yes it's plugged in in case I choose to turn it or the connected 5bx on, but as a matter of daily listening, those just sit there idle with their power turned OFF and the tape loop of the Peach set to source.

The Behringer never was part of my system and is not today. He took it home that same day.

[mas]

Richard...just a couple of points...although I may not have to say anything as I suspect Chloe is already nipping at your ankles!

So that horn actually provides greater more uniform coverage? Who would have thunk it!? D@mn, and I liked it JUST for its looks! [] (The real irony is that as we all tend to focus on the LF Bass bin, that MF 402 horn is a charmer!)

See, and all this instead of simply replacing the LF (very nice, but unbalanced) DBX amp with a balanced Crown K2 and running balanced from the DX on and just sitting back and forgetting all of this as you stare at the horn!

And after having the luxury of having a pair of Jubilees, you just have to find something to complain about. Geeeeesh!

So, after watching all of the trouble you have caused in this thread, you own me at least one break as I don't relish the idea of having to deal with another plaintive call with a charming but whimpering K9 on the other end of the line wondering just what to do as she explains to me that she loves you, but....

[][]

I suggest you relax, listen to the speakers, and worry more about making the annual July 4 Smithville Fiddler's Jamboree!

[Coytee]

And after having the luxury of having a pair of Jubilees, you just have to find something to complain about. Geeeeesh!

Ain't that the truth [H]

Sometimes it's just impossible to quiet the idiot inside of me.

[mas]

Oh, and if having the Jubilees isn't enough, you are lucky enough to be in East Tennessee!

Your cup runneth over!

[]

PS: Mark,the DBX to which I refer is a very overbuilt (albeit unbalanced) DBX amplifier, not a DBX processing unit (although I guess one could make the purist's case that an amp is a processing unit... oh well... ) Sorry for the additional confusion! Its all Richard's fault! [][]

[Coytee]

Because of that I typically do NOT listen to anything with the dbx unit in the circuit. Yes it's plugged in in case I choose to turn it or the connected 5bx on, but as a matter of daily listening, those just sit there idle with their power turned OFF and the tape loop of the Peach set to source.

------------------------

Are you saying you have a dbx plugged into the tape loop but turned off? If so, that might be where all the gain is going. The TAPE OUT jack is always connected to the source selector and is ahead of the volume control. This is true no matter where the SOURCE/TAPE selector is positioned. If the dbx is "dead" (powered off) it might present a dire load or even a short to the selector switch. Remove the dbx from the TAPE OUT jacks and see if your gain is restored.

Do I understand you correctly in that you're saying if I have "nothing" attached to the tape in/ tape out jacks I'll have "X" signal going through the system. If I change it though and attach something to the tape loop jacks BUT the item is turned off AND the tape selector is set to SOURCE, that I still might get a lag on signal strength??!!!

I would have NEVER expected that!! Good... you can bet I'll give that a double check and see if that makes a difference. Follow up question though, wouldn't it make reasonable sense that if a dead unit (turned off) and tape selector set to 'source' sapped signal strength, that if I had the tape selector set to TAPE and I had the dbx unit(s) (there are two of them) turned ON, that I should regain that gain? If that logic is reasonable then I'll make comment that there is no noticable gain with the dbx units turned on and selector set to 'tape'.

Regardless of your answer, I'll certainly give that a try. After all, it WAS you who figured out the DC feeding back out the inputs on my OTL amps causing other issues, all based on an innocuous statement that I thought was unrelated.

You sure you're not Sherlock Holmes reincarnated?

[Y]

[Coytee]

Oh, and if having the Jubilees isn't enough, you are lucky enough to be in East Tennessee!

Your cup runneth over!

[]

PS: Mark,the DBX to which I refer is a very overbuilt (albeit unbalanced) DBX amplifier, not a DBX processing unit (although I guess one could make the purist's case that an amp is a processing unit... oh well... ) Sorry for the additional confusion! Its all Richard's fault! [][]

Sorry Cupcake... I think Mark got it right. I DO have the dbx amp which you're aware of. I ALSO have a dbx 5bx and a dbx 14/10 eq which you might NOT be aware of and both of those are plumbed into the tape loop of the Peach (although I rarely use them, hence his comments)