Matching amp(s) to speakers; speaker continuous power capability unknown

[PENG]

Thanks for the bi-amp info. Given the reference in the piece to passive bi-amping as "fool's bi-amping," are its documents benefits negligible enough not to bother with it unless I were employing an external crossover (the speakers' manual suggests the employment of a two-way electronic crossover and provides formulae for setting high and low pass frequencies)? At this point, I think I am going to separately amplify the front speakers whether I go with a pre/pro or AVR w/ front channel pre-out, but I'm trying to determine whether the money is better spent on a single nice stereo power amp or matching pair for the fronts.

It seems that your questions/concerns have already been addressed, are you ready to make a decision now or still have specific questions or concerns not dealt with yet?

 

[CMcD-USC]

It seems that your questions/concerns have already been addressed, are you ready to make a decision now or still have specific questions or concerns not dealt with yet?

My original questions re: amplifier power have been answered yes (and thanks to those who offered advice), but I would appreciate any insight on the follow-up question re: cost/benefit of bi-amping without an external crossover, as the cited article seemed to be tepid at best re: passive bi-amping.

 

[Verdinut]

My original questions re: amplifier power have been answered yes (and thanks to those who offered advice), but I would appreciate any insight on the follow-up question re: cost/benefit of bi-amping without an external crossover, as the cited article seemed to be tepid at best re: passive bi-amping.

Passive bi-amping, which means using two amps on one speaker cabinet without the use of an electronic crossover, is usually a waste of money without any SQ improvement. The only exception would be to have more power and headroom for the low frequency driver. It can be done only on systems which have a separate crossover filter for the highs and another one for the low frequencies. Those speakers have 4 terminal connectors which are jumped for a single amp use.

 

[PENG]

My original questions re: amplifier power have been answered yes (and thanks to those who offered advice), but I would appreciate any insight on the follow-up question re: cost/benefit of bi-amping without an external crossover, as the cited article seemed to be tepid at best re: passive bi-amping.

Active bi-amp, in my opinion is overrated. Objectively speaking, if done well the main benefits would be improved efficiency. Subjectively, I don't think the so called purist audiophile type would like it because of the added electronic hardware and software/processing involved.

For passive bi-amp, it is easy to do it right by simply using identical amps, and the theoretical benefits are well grounded on science, but I think very few people would believe such benefits include audible difference.

By the way, you mentioned the local guy tried to sell you an Anthem AVR. I think if you go by facts and figures, you are better off staying with the major brands such as D+M and Yamaha's. If you have time, there are quite a few reviews on ASR that allows you to compare their specs and measurements. From 20,000 ft level, you can just take a look of the chart below that compares their distortions + noise bench measurements and draw you own conclusion. I would say the MRX-1120 looks good except the high price. The MRX-520 ranks near the bottom, the only AVR that did worse than the NAD T758 V3.

www.audiosciencereview.com

 

[CMcD-USC]

Active bi-amp, in my opinion is overrated. Objectively speaking, if done well the main benefits would be improved efficiency. Subjectively, I don't think the so called purist audiophile type would like it because of the added electronic hardware and software/processing involved.

For passive bi-amp, it is easy to do it right by simply using identical amps, and the theoretical benefits are well grounded on science, but I think very few people would believe such benefits include audible difference.

By the way, you mentioned the local guy tried to sell you an Anthem AVR. I think if you go by facts and figures, you are better off staying with the major brands such as D+M and Yamaha's. If you have time, there are quite a few reviews on ASR that allows you to compare their specs and measurements. From 20,000 ft level, you can just take a look of the chart below that compares their distortions + noise bench measurements and draw you own conclusion. I would say the MRX-1120 looks good except the high price. The MRX-520 ranks near the bottom, the only AVR that did worse than the NAD T758 V3.

www.audiosciencereview.com


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Excellent, thanks much for the info. I was actually intrigued by Emotiva, which seems to review well and be reasonably priced relative to some of the more marketed names in higher-end audio.

 

[lovinthehd]

FWIW Emotiva can be buggy or even lacking promised features with their pre-pros, particularly on newer releases. Their amps generally seem to do fine altho they refused to service Gene's (AH's founder/president) flagship Emotiva amp that needed repair. For the price of their pre-pros I'd probably stick with Marantz or Yamaha myself, altho personally I'm fine with an avr with pre-outs. I would not bother passively bi-amping, particularly with an avr, and active bi-amping I'd only do for a diy speaker project of my own....by taking out a given speaker's passive crossover and substituting an external active one would you really improve that much on the original design to make it worth it?

 

[CMcD-USC]

FWIW Emotiva can be buggy or even lacking promised features with their pre-pros, particularly on newer releases. Their amps generally seem to do fine altho they refused to service Gene's (AH's founder/president) flagship Emotiva amp that needed repair. For the price of their pre-pros I'd probably stick with Marantz or Yamaha myself, altho personally I'm fine with an avr with pre-outs. I would not bother passively bi-amping, particularly with an avr, and active bi-amping I'd only do for a diy speaker project of my own....by taking out a given speaker's passive crossover and substituting an external active one would you really improve that much on the original design to make it worth it?

Thanks for that info... I think if I went the Emotiva route I’d probably go with their XMC-1 refurb AVR pre-pro (they have a trade-up program for the new XMC-2 and consequently are doing a fair amount of recondition/resale of the traded-in units... as I’m only looking to do 5.1 or possibly 7.1 with a 4K TV and the speakers I have, the newer generation probably offers functionality that I don’t necessarily need.

Interestingly (although this may be common; I don’t know because I don’t know much about active crossovers), the Snell instruction manual suggests that a two-way electronic crossover can/should be incorporated in conjunction with rather than in lieu of the speakers’ internal crossovers, with recommended high-pass settings on 1/4 the speakers’ crossover frequency (listed at 2.7 kHz) and low pass at 4x the speakers’ frequency “to assure that the speaker’s internal crossover network will continue to have its optimal amplitude and phase response characteristics.” It seems like a lot of what I’ve read about active crossovers assumes either a DIY situation or a rewiring of a factory-made speaker to disable/remove the passive crossover. Is what Snell is suggesting a shortcut that would mitigate the potential benefit of incorporating an active crossover?

 

[lovinthehd]

Thanks for that info... I think if I went the Emotiva route I’d probably go with their XMC-1 refurb AVR (they have a trade-up program for the new XMC-2 and consequently are doing a fair amount of recondition/resale of the traded-in AVRs... as I’m only looking to do 5.1 or possibly 7.1 with a 4K TV and the speakers I have, the newer generation probably offers functionality that I don’t necessarily need.

Interestingly (although this may be common; I don’t know because I don’t know much about active crossovers), the Snell instruction manual suggests that a two-way electronic crossover can/should be incorporated in conjunction with rather than in lieu of the speakers’ internal crossovers, with recommended high-pass settings on 1/4 the speakers’ crossover frequency (listed at 2.7 kHz) and low pass at 4x the speakers’ frequency “to assure that the speaker’s internal crossover network will continue to have its optimal amplitude and phase response characteristics.” It seems like a lot of what I’ve read about active crossovers assumes either a DIY situation or a rewiring of a factory-made speaker to disable/remove the passive crossover. Is what Snell is suggesting a shortcut that would mitigate the potential benefit of incorporating an active crossover?

I just don't see the point of getting an external active crossover and still leaving any passive crossover in place, can't imagine adding filters together is a good idea but I'd have to pass to those more familiar with Snell's intention/implementation.

If you're just doing basic 5.1/7.1 you might also consider the Outlaw 976.

 

[CMcD-USC]

I just don't see the point of getting an external active crossover and still leaving any passive crossover in place, can't imagine adding filters together is a good idea but I'd have to pass to those more familiar with Snell's intention/implementation.

If you're just doing basic 5.1/7.1 you might also consider the Outlaw 976.

I read the only extensive review of the Outlaw that I could find and the reviewer seemed very impressed; certainly can't argue with the cost, either, so I'll definitely add that into the pool of candidates. It seems Outlaw is trying to occupy a similar niche as Emotiva but has been more reliable with its firmware.

Do you have any experience with their amplifiers? The Audio Science review gave their 5000 model a recommendation but sort of damned it with faint praise: “it‘s fine for what it is,” or something along those lines. The Emotiva XPA amps seem to review well elsewhere but only their lower end was reviewed on AS.

 

[lovinthehd]

I read the only extensive review of the Outlaw that I could find and the reviewer seemed very impressed; certainly can't argue with the cost, either, so I'll definitely add that into the pool of candidates. It seems Outlaw is trying to occupy a similar niche as Emotiva but has been more reliable with its firmware.

Do you have any experience with their amplifiers? The Audio Science review gave their 5000 model a recommendation but sort of damned it with faint praise: “it‘s fine for what it is,” or something along those lines. The Emotiva XPA amps seem to review well elsewhere but only their lower end was reviewed on AS.

The 5000/7000 amps I'd never considered, if I get an amp its going to be more powerful, altho they seem to be fine; the M2200 monoblocks are somewhat more interesting particularly when they had the great pricing for a three-fer. The upper models from there afaik are made by ATI, tho, and can be well priced (like Monoprice's Monolith amps). I'd considered Emotiva several years back and lately just don't seem all that interesting but I don't really need amps, have extras and my last several have been Crown XLS amps.

ps I don't put too much into Amir's sneers.

 

[CMcD-USC]

The 5000/7000 amps I'd never considered, if I get an amp its going to be more powerful, altho they seem to be fine; the M2200 monoblocks are somewhat more interesting particularly when they had the great pricing for a three-fer. The upper models from there afaik are made by ATI, tho, and can be well priced (like Monoprice's Monolith amps). I'd considered Emotiva several years back and lately just don't seem all that interesting but I don't really need amps, have extras and my last several have been Crown XLS amps.

ps I don't put too much into Amir's sneers.

Thanks for that... hadn’t noticed those when I looked through their amps the first time. I’ve been thinking about the best way to break up my purchase to ensure maximum preservation of marital tranquility, so I may pick up a pair of those for the front channels and a better disc player now and keep my current AVR in the system, then pick up the pre/pro and amps for the other speakers in a few months.

I’ve also been toying around with buying a couple if the Hypex DIY kits that tested so well on ASR. I’ve built computers and made DIY guitar pedals in the past, and they didn’t look particularly challenging. Only concern is that the vendors of the better-known kits all seem to be European, and it can be a pain to get international purchases through customs, not even accounting for COVID related shipping delays.

 

[lovinthehd]

Sounds like a reasonable plan. The hypex or purifi kits could be interesting. Why is it a pain to get thru Customs particularly? Shipping terms put the burden on you to arrange your own clearance or ? That's my past life...a US Customs broker.

 

[CMcD-USC]

Sounds like a reasonable plan. The hypex or purifi kits could be interesting. Why is it a pain to get thru Customs particularly? Shipping terms put the burden on you to arrange your own clearance or ? That's my past life...a US Customs broker.

I purchased a guitar from a merchant in London about a year back and it was a real headache getting it through, but now that I think about it, that was probably due to CITES rather than general import hurdles. Probably okay with import of electronics (although I pre-ordered a guitar practice amp in early March that is of Chinese manufacture, and I’m still waiting for it to ship because of COVID.

 

[lovinthehd]

I purchased a guitar from a merchant in London about a year back and it was a real headache getting it through, but now that I think about it, that was probably due to CITES rather than general import hurdles. Probably okay with import of electronics (although I pre-ordered a guitar practice amp in early March that is of Chinese manufacture, and I’m still waiting for it to ship because of COVID.

LOL no exotic woods in the amp kits. Not sure if an amp kit would be subject to the FCC requirement (at least I imagine that's still a thing, been almost 7 years since I retired, tho). Could also have to do with the shipper's experience (like providing CITES cert.) and terms sold under as to who was responsible for what for transport/Customs.

 

[CMcD-USC]

LOL no exotic woods in the amp kits. Not sure if an amp kit would be subject to the FCC requirement (at least I imagine that's still a thing, been almost 7 years since I retired, tho). Could also have to do with the shipper's experience (like providing CITES cert.) and terms sold under as to who was responsible for what for transport/Customs.

I communicated with the Hypex kit manufacturer yesterday and he said that shipping to the US was not a problem and that customs was taken care of through the shipper and included in the quoted shipping costs. As it turns out, they do have a reseller of their products in the US, but when I contacted them after not finding the kit on their website, they told me that they don't carry this particular kit because they believe that the build documentation included with the components was insufficient for kit builders of all levels (I looked through it and it seemed pretty straightforward to me, but maybe I'm too unskilled to know better!), so if I order a pair of kits for the front channels, I will purchase them from the source in the Netherlands.

This leads to my final question: are there any issues to be cognizant of running the front channels through totally different (brand, output, etc.) amps than I'd be running center/rear through? The NC400 kits are 400 watts/4 ohm (my front channels are 6 ohm nominal), and I'd likely run the other three through the Outlaw 2220 monoblocks or a three-channel, each of which are rated 200 watts into 8 ohms (rear channels are 6-ohm and center is 8-ohm nominal).

 

[PENG]

This leads to my final question: are there any issues to be cognizant of running the front channels through totally different (brand, output, etc.) amps than I'd be running center/rear through? The NC400 kits are 400 watts/4 ohm (my front channels are 6 ohm nominal), and I'd likely run the other three through the Outlaw 2220 monoblocks or a three-channel, each of which are rated 200 watts into 8 ohms (rear channels are 6-ohm and center is 8-ohm nominal).

If they all have more than enough output for the speakers, you just have to make sure they are all level matched, and the preamp has high enough clean output to drive those amps to well above their rated output. The one to watch is the preamp for the NC400 that if I remember right, typically has gains as low as below 26 dB.

 

[CMcD-USC]

If they all have more than enough output for the speakers, you just have to make sure they are all level matched, and the preamp has high enough clean output to drive those amps to well above their rated output. The one to watch is the preamp for the NC400 that if I remember right, typically has gains as low as below 26 dB.

You were correct on the gain (min/typ/max for the kit is listed at 25.3/25.8/26.3 dB). To make that determination of what output is needed, should I be comparing the VRMS and VPEAK for the preamp to the numbers computed for the power amplifier to insure that the preamp standard and peak voltage exceeds what is listed for the amp?

The NC400's datasheet has a section entitled "Input Sensitivity" (see attached JPEG) that reflects those numbers at 2.05V/2.90V and an ultimate calculation to show "the balanced input signal level for a desired output level," with the final calculation of 8.46 dBu (not sure how this last number figures into the determination).

The Outlaw 976 preamp spec sheet reflects preamp voltages of 2V (RCA) and 4V (XLR), with peak voltages of 4.5V (RCA) and 9.0V (XLR).

Using the formulae in the attached screen cap for 6-ohm nominal speakers (which I assume would be driven at 300W... the NC400 only shows ratings for 2 (580W), 4 (400W) and 8 ohms (200W)), I come up with 3.29VRMS and 4.65VPEAK. So would this mean that I am fine with the Outlaw 976 if I am using XLR connection between preamp and amplifier? Or did I just do a meaningless calculation because I am looking at the wrong thing entirely?

The other preamp I am considering is the Emotiva XM-1 refurb. Emotiva reflects their numbers differently, with a "Maximum Output Level (Analog)" of 5.5VRMS (RCA) and 11.0VRMS (XLR).

What you raise also begs another question. I was planning to buy my components in phases, using the two amplifiers through a front channel pre-out on a borrowed Marantz NR1602 AVR until I purchase a new preamp later this year. I do not see where the Marantz manual even mentions the front-channel pre-out other than showing it on a diagram of the back panel. How would I make the determination of whether the temporary AVR has sufficient clean output?

 

[PENG]

Using the formulae in the attached screen cap for 6-ohm nominal speakers (which I assume would be driven at 300W... the NC400 only shows ratings for 2 (580W), 4 (400W) and 8 ohms (200W)), I come up with 3.29VRMS and 4.65VPEAK. So would this mean that I am fine with the Outlaw 976 if I am using XLR connection between preamp and amplifier? Or did I just do a meaningless calculation because I am looking at the wrong thing entirely?

I don't know where your 3.29 Vrms came from. Based on your assumption of 6 ohm load, at 300 W average, the preamp output would need to be approx. 2.18 Vrms, the Outlaw 976 is rated 2 V so you should be fine. I would have post my own calculator but I did it in Excel. You can try sengpielaudio linked below, for a calculator that can do the same. The calculated values are for RCA/unbalanced, double it for XLR/balanced (typically speaking, there could be exceptions in some odd cases..)

Gain factor dB conversion to factor ratio gain conversion to level in decibels dB amplitude voltage gain field quantity dBu dBm dBW dBV dBmV dBµV dBu energy size power voltage damping factor attenuation amplitude amplification acoustic intensity sound pressure factor ratio voltage gain power loss level decibel dB - sengpielaudio Sengpiel Berlin

gain factor ratio gain conversion to level in decibels dB amplitude voltage gain conversion to factor field quantity dBu dBm dBW dBV dBmV dBµV dBu energy size power voltage damping attenuation amplitude amplification acoustic intensity sound pressure factor ratio voltage gain powerloss level...

www.sengpielaudio.com

The question is, what is an acceptable THD+N level for you, and Outlaw did not provide such specs for the pre out at the 2 V unbalanced, i.e. 4 V balanced level, so that's an unknown regardless. Not my choice for sure but if you like it, that's your choice.

The other preamp I am considering is the Emotiva XM-1 refurb. Emotiva reflects their numbers differently, with a "Maximum Output Level (Analog)" of 5.5VRMS (RCA) and 11.0VRMS (XLR).

That one would seem to have better specs than the Outlaw. My choice would still be the AVR-X3600H, just pretend it is a preamp and save a lot of cash..

What you raise also begs another question. I was planning to buy my components in phases, using the two amplifiers through a front channel pre-out on a borrowed Marantz NR1602 AVR until I purchase a new preamp later this year. I do not see where the Marantz manual even mentions the front-channel pre-out other than showing it on a diagram of the back panel. How would I make the determination of whether the temporary AVR has sufficient clean output?

The NR1602 has FL/FR pre out, whether they have clean output or not it depends on how you define clean. Based on available published bench measurements online, the AVR-X3600H does have what most would consider clean output to 2 V and above, much cleaner than the Marantz AV7705, and even slightly cleaner than the flag ship AV8805. You may have hard time finding one though. If not, then I would grab the AVR-X4500H, no measurements on that one but I see no reason why it won't be as good.

 

[Pogre]

I have had speakers blown by excessive power, on gear that had no max volume setting, by my roommate and business partner Old analog gear that didn't have that max volume setting feature, but if it had, that wouldn't have happened. Some partying was involved and had I been there it wouldn't have happened but I was working. He just wanted to see how loud it could get but knew little about my gear (which was somewhat fragile speakers with a ton of power).

Oh no, I never heard you tell that story before! I would feel horrible if I blew somebody's speakers up like that. What were they?

 

[Pogre]

Thanks for that info... I think if I went the Emotiva route I’d probably go with their XMC-1 refurb AVR pre-pro (they have a trade-up program for the new XMC-2 and consequently are doing a fair amount of recondition/resale of the traded-in units... as I’m only looking to do 5.1 or possibly 7.1 with a 4K TV and the speakers I have, the newer generation probably offers functionality that I don’t necessarily need.

Interestingly (although this may be common; I don’t know because I don’t know much about active crossovers), the Snell instruction manual suggests that a two-way electronic crossover can/should be incorporated in conjunction with rather than in lieu of the speakers’ internal crossovers, with recommended high-pass settings on 1/4 the speakers’ crossover frequency (listed at 2.7 kHz) and low pass at 4x the speakers’ frequency “to assure that the speaker’s internal crossover network will continue to have its optimal amplitude and phase response characteristics.” It seems like a lot of what I’ve read about active crossovers assumes either a DIY situation or a rewiring of a factory-made speaker to disable/remove the passive crossover. Is what Snell is suggesting a shortcut that would mitigate the potential benefit of incorporating an active crossover?

I can't imagine bi amping with active crossovers without removing the passive ones first? If that were to improve anything it would suggest to me that the speakers aren't designed very well. They should sound great on their own without the need to add external filters.