Bi-amp Revel F208s using Denon 8500HA?

[pmar4015]

I realize the following is controversial (in terms of efficacy (or lack thereof)) but I can’t help but think there may be some benefit in bi-amping my front Left and Right Revel F208 speakers in my current 7.1.2 setup. To complicate matters, I am running Three Outlaw 2220s to power my FRONT Left, Center, and Right speakers (center speaker is a Klipsch R-5800 W II (behind an acoustically transparent projection screen)).

I am thinking that if I repurpose two of the three Outlaw 2220s for use as external amplification to power my two main surrounds (keeping one Outlaw 2220 powering my Center Channel (as I am doing now)) and then bi-amping my Revels via the onboard 8500HA amplifiers I ‘may’ receive some benefit considering the 8500HA has 13 on-board amplifiers and I am currently only using 6 on-board amplifiers (understanding the Outlaw 2220 is rated for 200 watts into 8 ohms but maybe if I bi-amp (thus using 8 on-board amplifiers) I can squeeze out maybe 250 watts per Left/Right channel?). My goal is to put as much power as I can into the Revels (given they are rated for up to 300 watts) using my current set-up.

Here is my current setup -

Receiver: Denon 8500HA (powering L/R Main Surround speakers; Top Middle Ceiling Atmos Speakers; Back surround Left/Right speakers)
External Amps: Three Outlaw Audio 2220 monoblocks (powering Main L/R/C speakers)
Speakers: (A) Bed Layer (7 spkrs) - (i) Front L/R: Revel Proforma3 F208; (ii) Center: Klipsch R-5800-W II (behind an acoustically transparent projection screen); (iii) Main Surround L/R: ELAC Debut 2.0 OW4.2; (iv) Rear Surround L/R: ELAC Debut 2.0 OW4.2 ; (B) Height Layer (2 speakers) (i) Top Middle L/R: Revel IW65; (C) Subwoofers (5 spkrs) - SVS PB-1000 (4 subs)/Monoprice Monolith M-215 (1 sub)
Gaming Console: XBOX Series X; Blu-ray Player: Sony UBP- X700(M); Projector: Sony VPL-VW325ES; Streaming Device: Apple TV (2021 gen)/Hardware DSP: MiniDSP 2X4 HD (Managing 3 subs (4 SVS PB-1000 co-located; collapsing into 2 subs)/Software DSP: MultEQ-X

Or maybe I just buy two more Outlaws 2220s to bi-amp the Revels (or just do nothing at all)?

Thoughts?

 

[Wayne A. Pflughaupt]

It won't cost anything to try it with the 8500, so I'd start there.

Regards,
Wayne

 

[Sonnie Parker]

I'm with Wayne... try the 8500 and see if you notice any difference. Chances are pretty good you are not anywhere close to maxing out the 2220s as it is, so you might gain a little headroom, but I'm not sure it would ever be needed, unless you are pushing insanely loud levels.

 

[pmar4015]

I'm with Wayne... try the 8500 and see if you notice any difference. Chances are pretty good you are not anywhere close to maxing out the 2220s as it is, so you might gain a little headroom, but I'm not sure it would ever be needed, unless you are pushing insanely loud levels.

Thanks to both!

 

[Todd Anderson]

If you try it, definitely come back and report on your findings!

I agree with Wayne and Sonnie... other than the hassle of setting it up, it's probably a no-brainer to roll the dice and see what happens. Headroom can be invaluable.

 

[pmar4015]

Funny enough, after bi-amping my Revels F208s and consequently rerunning auto-calibration (Audyssey MultEQ-X) I discovered I actually have a problem with one of the tweeters in in one of my Revel F208 speakers.

I am 99.99% certain my issue has absolutely nothing to do with bi-amping considering the speaker sounded ‘off’ prior to bi-amping (which was the reason I went down the bi-amping road to begin with). I have a local guy who repairs speakers therefore I should be up and running with a replacement tweeter in the near-term and will report back upon completion of the repair.

Just goes to show you the importance of regularly running auto-calibration/REW if for no other reason but to confirm there are no problems with the health of the user’s system (e.g. bad speaker components, faulty connections, etc. etc.).

 

[Sonnie Parker]

Well... that's a bummer, but thankfully, it sounds like it won't be too much of a problem to fix.

 

[pmar4015]

Well... that's a bummer, but thankfully, it sounds like it won't be too much of a problem to fix.

Thanks. For what it is worth, I swapped out my Revels for a pair of Klipsch RP-8000s (first gen) I keep as a backup. With the klipsch’s I couldn’t really tell a difference bi-amping using the onboard Denon 8500HA amps vs single amping via my Outlaw 2220s

 

[pmar4015]

But I remain curious as to how bi-amping will treat the Revels.

will let you know!

 

[Sonnie Parker]

Yeah... the Klipsch are likely a LOT more sensitive than the Revels.

 

[pmar4015]

100% - ain’t no doubt about it in terms of sensitivity

 

[DonH57]

I'd leave it the way it is. The Outlaws have more power and as separate amps do not share power supplies so using them to drive the front three, which generally consume the most power and deliver the most sound, makes sense to me.

Bi-amping with an AVR provides essentially no power benefit because "passive" bi-amping does not put crossovers before the internal amplifiers. All speaker outputs are still full-range, so even though the power delivered to highs and lows will change, the voltage from each amplifier is the same, so there is no real headroom benefit nor increase in power. Another way to think of it is that, if you have a 100 W amplifier, the most any driver sees is 100 W. If you use two 100 W amplifiers driving different frequency bands, then each driver can still only see a maximum of 100 W -- it is not the same as using a 200 W amplifier. In terms of voltage across the speaker terminals, 100 W into 8 ohms is about 28 V, while 200 W is 40 V (power is not linear). Two 100-W amps can still only provide 28 V each, not 40 V, so cannot double the power (again, power is not linear, and no driver can see 40 V from a 28 V source so you do not double the power by bi-amping). It is also less efficient since you need low-level stages and bias current (power) for each amplifier, so two 100 W amps will be less efficient (all else equal) than one 200 W amp.

Other considerations: AVR power amps share power supplies and thermal management so off-loading those amplifiers helps the AVR. Also, even if you double the power (which bi-amping does not do), that is a 3 dB increase in volume (SPL), which is not a large change. Here is the table for sound volume in the midrange:

1 dB is barely noticeable and requires 1.26x the power
3 dB is what most people hear as "a little louder" and requires 2x the power
6 dB is significantly louder and requires 4x the power
10 dB sounds twice as loud and requires 10x the power
17 dB is the headroom for music and requires 50x the average power
20 dB headroom for movies requires 100x the power

Most people use less average power and more peak power than they think. At 1 W average power, a loud peak (20 dB) requires 100 W. If 200 W from your Outlaw is not enough, you probably need a lot more power.

This article discusses bi-amping in general: https://www.audiosciencereview.com/forum/index.php?threads/bi-amping-101.22817/

As others have said, it will not hurt to try except for the time and effort, but perception bias is very powerful and chances are you will (think you) hear a difference even if it is not really there. Decades ago I knew I could hear many things that blind testing showed was not there. It was a a humbling revelation.

FWIWFM - Don

 

[ddude003]

Something to consider is the difference in Horns, ESLs and magnetic planers verses traditional cone speakers... And the the Voltage Paradigm verses the Power Paradigm amplifiers driving them... This is the area I think bi and tri-amping makes the most sense...

Resources: Paradigms in Amplifier Design

Voltage Paradigm vs. Power Paradigm. Competing Paradigms in Amplifier and Loudspeaker Design, Test, and Measurement.

www.atma-sphere.com

 

[DonH57]

Something to consider is the difference in Horns, ESLs and magnetic planers verses traditional cone speakers... And the the Voltage Paradigm verses the Power Paradigm amplifiers driving them... This is the area I think bi and tri-amping makes the most sense...

http://www.atma-sphere.com/en/resou...Power Paradigm assumes that,4, 8 and 16 ohms.

I like Ralph a lot and we interact on several forums. I am not sure that article is relevant for this thread, however, as the Outlaw amplifiers and AVR in question are designed as voltage sources, and speakers mentioned are designed to be driven by voltage sources, as are most consumer amps and speakers for many years.

Horns tend to be more efficient and use compression drivers but, like conventional speakers, tend to have fairly complex impedance curves (the crossover being a big contributor, as for any speaker). The drivers and horns make them highly sensitive so they require less power than most other speakers.

ESL panels tend to fall in impedance at high frequency, often to very low impedance (1 ohm and below), so can be a challenging load. The panel itself looks like a big capacitor, but due to the coupling transformer (to isolate the high-voltage DC needed for the electrostatic field from the signal input), the impedance is often inductive and not capacitive at high frequency. Planar magnetics tend toward resistive with low phase angles, usually due to the crossovers, and low'ish (but flat'ish) impedance so are not terribly demanding from an impedance point of view (good for tube amps). Both ESLs and planar dynamics tend to low sensitivity so require a lot of power to play loud, and then you have to watch levels because of their limited excursion (and resulting high distortion for large excursion).

I am not sure how the argument for multiway amplification and crossovers plays into speaker type, though it plays into power needs and as Ralph says different types of drivers have different drive requirements. In this case, the amp and AVR are conventional, so I am not sure the power vs. voltage vs. current drive argument applies?

I bi-amped my Magnepans way back when I was using them, but also used a custom crossover with higher order (steeper slope) than the stock crossover so I could use a lower-power treble amp. Most of the bi- or tri-amped systems I worked with were for sound reinforcement, i.e. large sound systems for concert venues, where being able to choose the amp for the power required was a big benefit in overall size, weight, power, and cost of the system.