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WVPaul

Biamping crossover suggestion not diy

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Page 8 says 250watts@ 8 ohms, but it's not the whole list of specs, but an overview of each xseries. The sales guys must have written all the copy.

Just another glaring example of Emotiva incompetence.

Other possible scenarios:

1. True and accurate test results were used for the overview.

2. An incredibly inept technician mistook the overview info for the specifications sheet - concluded testing once the XPA-2 met said "specs". This might explain the questionable results in the Audio Precision Spec Test Data pdf - and a few other things.

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so if it is 260 watts at 1khz, wonder how many watts that is at 20khz?

Or 15hz

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Dtel, Can you reply about when turning on and off does it pop or thump, this is one reason I passed on Parasound, but I never found any comments about it on the Crown. Till now.

Sorry I didn't see this, yes they do thump a little, one almost always and the other on occasion and only in the bass bins and it's not loud at all, not enough for me to worry at all.

Anyway I usually leave them on, at less than 15 watts idle it's not a big deal especially when they are working 6-8 hours a day.

Thanks about the thumping, I will see how bad mine is after I get it, some comments stated its noticeable, some stated no thump, but I guess you can remedy it with a cap or a time delay switch without too much effort.

A relay will protect from on/off thumps/pops. A cap will protect from on/off thumps/pops and block DC - although it may cause phase shift issues.

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If your sources are digital, I would recommend a digital speaker processor *with a digital input* (AES or SPDIF). This will allow you to minimize the number of A/D and D/A conversions in the playback chain. In my experience, this makes a huge difference in sound quality. I also recommend a DSP running at 96 KHz. I've measured a number of DSP boxes, and the 96 KHz boxes generally behave better in the top octave.

I also recommend a digital speaker processor so you can "time-align" the various ranges.

IIRC member Cask05 has a bi/tri-amping FAQ somewhere on the forum.

Another thing that helps, especially with "professional" speaker processors is a set of passive fixed attenuators between the processor and the power amps. This allows running the processor at the highest possible level, therefore using the most number of bits in the processor. The attenuators reduce the signal in the analog domain to a level that won't blast you against the wall and/or destroy your speakers. This also reduces any noise upstream of the attenuators.

I have a Yamaha SP2060 speaker processor, Crown D-75 (not A) amps tri-amping Klipschorns. SPDIF sources are converted to AES3 with a HOSA CDL-313. The SP2060 has an AES3 input. 0 dBFS in the SP2060 is +24 dBu (about 12 Volts RMS). The amps have 26 dB of gain and 0.812 Volts sensitivity. So running the SP2060 wide open into the amps (with the amp level controls wide open) would overdrive the amps by about 27 dB. The stepped attenuators inbetween the SP2060 and the amps are usually set for 36 dB of loss. This allows setting the amp level controls wide open so the gain is always calibrated. The relative levels of woofer, squawker and tweeter are set in the SP2060.

As far as determining crossover settings goes, I recommend measuring the transfer function of the speaker and adjusting for flat, then roll off the high end to taste. Transfer function can be measured with Room EQ Wizard, but room reflections may limit what you can measure. I should also warn you that I have a strong measurement bias.

I'm looking forward to reading about your adventures!

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Greg,

Interesting comments about the stepped attenuators. Can you explain a little more about why you use those when you have the amp gains to reduce the input to the amps? What advantage do the attenuators provide? Also, can you let us know the name and type of attenuators you are using? I'm interested.

What I did in my system was reduced the amp gains such that the processor has got its equired level of input singal from the preamp but does not overdrive the amps. I just used the amp gains for this.

Edit: Another question Greg. I see you recommend a digital input on the processor. I use a DAC but also a McIntlsoh preamp so my sources are not directly connected to the processor. Is your DAC (I'm assuming this is what you use) connected directly to the processor?

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Got the crossover hooked up, cables re-run, just wanted to do a quick check make sure everything was correct. Turned on and got that beautiful sounding ground hum. Did a quick search on Klipsch forums and found out this will happen when switching from RCA > XLR.

The signal flow is Onkyo 1008 pre-out RCA > to DBX equalizer XLR > to Ashly XR-1001 crossover XLR > Amp XLR > banana plug into speaker.

One recommendations was this > http://www.sweetwater.com/store/detail/HumXLR/

I guess install this before the DBX equalizer.

I don't mind spending the money if this will fix the problem.

Just looking for any thoughts, thank you.

edit: I also read snipping lead 1wire at the XLR connection might fix this issue, but might drop signal level also

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Interesting comments about the stepped attenuators. Can you explain a little more about why you use those when you have the amp gains to reduce the input to the amps? What advantage do the attenuators provide? Also, can you let us know the name and type of attenuators you are using? I'm interested

I don't mean to speak for him but he might be coming from a perspective of amps without gains.

I know when I was using my BX-1 and McIntosh 2102, they did not have gain controls. The input sensativity of the BX1 if I recall, was 1v. You might remember me making some joking comments once at one of the Klipsch gatherings when I was asking Roy why HIS Dx38 had nice blinky lights and I wasn't having ANY.

That was my issue.

Today, with the K2's, I have them around 25% volume on the gains and I can max my Peach as well as the Dx38 and a side byproduct is reduce the noise in the system when it's down low.

I could not do this with the fixed input amps so my guess is he's talking about putting the attenuater in front of something like those.

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Greg,

Interesting comments about the stepped attenuators. Can you explain a little more about why you use those when you have the amp gains to reduce the input to the amps? What advantage do the attenuators provide? Also, can you let us know the name and type of attenuators you are using? I'm interested.

What I did in my system was reduced the amp gains such that the processor has got its equired level of input singal from the preamp but does not overdrive the amps. I just used the amp gains for this.

Mark--

I use the stepped attenuators so that the overall gain after the DSP is repeatable. With stereo tri-amp that's 6 gains that have to track with fractional-dB repeatability. There's no way the level controls on the amps can do this.

I built the attenuators myself. SMT resistors (painful), a double-sided circuit board and an Electro-Switch 2-pole 8-position switch. Balanced ladder configuration at 1210 ohms. 1210 ohms was chosen because it is a standard 1% resistor value, it's higher than the 600 ohms that the processor can drive, but low enough that a reasonable length of cable on the output won't produce significant high-frequency roll-off at 20 KHz.

Edit: Another question Greg. I see you recommend a digital input on the processor. I use a DAC but also a McIntlsoh preamp so my sources are not directly connected to the processor. Is your DAC (I'm assuming this is what you use) connected directly to the processor?

I don't use an external DAC in front of the Yamaha processor. The SPDIF from the CD player or DVD player gets converted to AES3. The AES3 signal goes into the Yamaha processor. All processing is in the digital domain until the DACs at the Yamaha outputs. This way there is only one A/D or D/A conversion in the signal path.

If we use a DSP processor with analog inputs the signal path is:

CD (dig) >> D/A >> processor input >> A/D >> DSP processing >> D/A >> power amps

A total of 3 A/D or D/A conversions. This is why I recommended the OP get a processor with a digital input *if his sources are digital*.

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Got the crossover hooked up, cables re-run, just wanted to do a quick check make sure everything was correct. Turned on and got that beautiful sounding ground hum. Did a quick search on Klipsch forums and found out this will happen when switching from RCA > XLR.

The signal flow is Onkyo 1008 pre-out RCA > to DBX equalizer XLR > to Ashly XR-1001 crossover XLR > Amp XLR > banana plug into speaker.

One recommendations was this > http://www.sweetwater.com/store/detail/HumXLR/

I guess install this before the DBX equalizer.

I don't mind spending the money if this will fix the problem.

Just looking for any thoughts, thank you.

edit: I also read snipping lead 1wire at the XLR connection might fix this issue, but might drop signal level also

The EBtech box has transformers in it. It might add some distortion. I would see if the hum can be reduced by other means first. Chasing hum can be an arduous task, but let's get started anyway:

With all controls set to the "normal" listening settings, turn off the power amps and let them discharge for a bit. Disconnect the audio cables between the Onkyo and the dBX. Turn the power amps back on. Is the hum still there?

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I don't use an external DAC in front of the Yamaha processor. The SPDIF from the CD player or DVD player gets converted to AES3. The AES3 signal goes into the Yamaha processor. All processing is in the digital domain until the DACs at the Yamaha outputs. This way there is only one A/D or D/A conversion in the signal path.

If we use a DSP processor with analog inputs the signal path is:

CD (dig) >> D/A >> processor input >> A/D >> DSP processing >> D/A >> power amps

A total of 3 A/D or D/A conversions. This is why I recommended the OP get a processor with a digital input *if his sources are digital*.

Most of my source is HDMI uncompressed digital (Blu ray).

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The EBtech box has transformers in it. It might add some distortion. I would see if the hum can be reduced by other means first. Chasing hum can be an arduous task, but let's get started anyway:

With all controls set to the "normal" listening settings, turn off the power amps and let them discharge for a bit. Disconnect the audio cables between the Onkyo and the dBX. Turn the power amps back on. Is the hum still there?

I won't be able to try this till tomorrow, but there are a lot of articles about when going from pre-out RCA to XLR, the results can be a hum. Rane has a whole page, describing ways to fix it, snipping lead 1 wire, isolation xfmr (Ranes version is balance buddy 44 and 22, Jensen transformers).

I will try your suggestions above, since that costs nothing. Next, I was going to try snipping the wire and see if that fixes it, (I have a spare one).

Thanks.

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Most of my source is HDMI uncompressed digital (Blu ray).

I don't think you can get SPDIF or AES3 from an HDMI source. Something about copyright.... So you will have to go the route of multiple D/A and A/D conversions. All the more reason to get a 24-bit/96 KHz DSP speaker processor if you eventually get a digital processor.

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I won't be able to try this till tomorrow, but there are a lot of articles about when going from pre-out RCA to XLR, the results can be a hum

I must have got lucky, that's exactly what I did RCA pre-out on HTR to XLR to EV-DX and no hum. It's not a fancy wire just regular Monoprice stuff.

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The EBtech box has transformers in it. It might add some distortion. I would see if the hum can be reduced by other means first. Chasing hum can be an arduous task, but let's get started anyway:

With all controls set to the "normal" listening settings, turn off the power amps and let them discharge for a bit. Disconnect the audio cables between the Onkyo and the dBX. Turn the power amps back on. Is the hum still there?

Hum is gone, after removing audio cables from the back of the Onkyo.

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The EBtech box has transformers in it. It might add some distortion. I would see if the hum can be reduced by other means first. Chasing hum can be an arduous task, but let's get started anyway:

With all controls set to the "normal" listening settings, turn off the power amps and let them discharge for a bit. Disconnect the audio cables between the Onkyo and the dBX. Turn the power amps back on. Is the hum still there?

Hum is gone, after removing audio cables from the back of the Onkyo.

If your RCA >> XLR cables have 2 conductors plus a shield and are wired like this:

RCA tip >> conductor A >> XLR pin 2

RCA sleeve >> conductor B >> XLR pin 3

RCA sleeve >> shield >> XLR pin 1

Disconnect the shields at the XLR ends and see if things improve. There is a possibility that a wire from the Onkyo ground screw to a chassis screw on the dBX will help when the shield is disconnected. It might also make things worse.

If the hum is not sufficiently reduced, the sure-fire hum killer is a pair of transformers. I recommend Jensen Isomax. IIRC they have a version with RCA in and XLR out. Expensive but worth it.

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Either the DBX or the Ashy may not like the Onkyo home audio component. Can you run the DBX on a tape monitor loop instead of after the preamp? I would remove the DBX if not (temporarily) and go direct from preamp to Ashly. I would also do a test by buying a whole lot of 3-2 cheater plugs and lift every power cord ground temporarily to see if you have a ground loop. This can be dangerous in the long run. Just do it temproarily. Hopefully it's a ground loop and not an impdeance mismatch. If it's an impedance mismatch I recommend changing the Onkyo to something else rather than using one of those "Clean box" components that supposedly fix the mismatch. They are no good for your system.

It sounds like you are getting the RCA-XLR straightened out as well.

Hey Greg, nice idea with the attentuators. I understand the issue of setting gains.........I have to do 8 channels. I use a mic and RTA on a PC. As long as no one touches any knobs all my channels stay perfectly balanced. My amp gains are set all over the place to get L/R balance. Some are barely cracked. But I get very low noise.

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I think I figured it out, after snipping pin 1 on the XLR, it made no difference. I pulled all cables and figured I would start putting everything back together one at a time. When running the subwoofer cable, it returned not to mention it scared the crap out of me. Never install a subwoofer cable with the sub on. I tried a second cable and it still returned. I have another sub I need to bring up from the basement and see if that works. Question - with 2 subwoofer outputs is there any difference in their electrical connection.

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I won't be able to try this till tomorrow, but there are a lot of articles about when going from pre-out RCA to XLR, the results can be a hum

I must have got lucky, that's exactly what I did RCA pre-out on HTR to XLR to EV-DX and no hum. It's not a fancy wire just regular Monoprice stuff.

I think I misspoke, there weren't a lot of articles, there were a few articles. Just wanted to set that straight.

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I think I figured it out, after snipping pin 1 on the XLR, it made no difference. I pulled all cables and figured I would start putting everything back together one at a time. When running the subwoofer cable, it returned not to mention it scared the crap out of me. Never install a subwoofer cable with the sub on. I tried a second cable and it still returned. I have another sub I need to bring up from the basement and see if that works. Question - with 2 subwoofer outputs is there any difference in their electrical connection.

I don't understand the question. Is your concern the power or signal connection(s)?

One thing about hum/gounding problems is that *everything* matters: physical proximity, AC power connections, whether or not the chassis are touching (electrically), physical position of interconnect cables etc.

If you can hook everything up except for the (powered?) subwoofer without objectionable hum, then things have been narrowed down considerably. Once you determine which equipment connection causes hum, please provide manufacturer and model information so I can find the manual online.

> Never install a subwoofer cable with the sub on.

Especially with RCA connectors. The tip usually connects before the sleeve, so there is no ground connection until the sleeve connects.

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