Question 4ohms speakers =/= 6-8 ohms amp: would this mis-match cause much less powerful sound/overall vol?

brandon77

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- Marantz AV7704 pre-amp
- Marantz 7055 5-Ch Amp: 140W(8 ohms, 20Hz-20kHz) x5
- Triad Silver Inroom LCR Monitors: Recommended Amp Power 50-200 watts
Impedance - 4 ohms
Sensitivity (db 1watt/1meter) - 92.5
Anechoic Frequency Response 70Hz-20kHz

- Triad Silver inroom Subs (2): Anechoic Frequency Response - 20Hz-200Hz
F3 -3db 20
Woofer Type - Ultra-low distortion aluminum cone woofer
Woofer Size - 12" /30cm
Sub Amp Type - Class A/B RackAmp
Sub Amp Power - 7
00 watts

- Triad Bronze Surrounds (sound fine).

Bottom line: at volume level 50 the overall sound is not much above a 2-3 person conversation. It's not until 65,70,75 that it really opens up and there's enough 'oomph' for movies or intense music listening.

I am receiving mixed messages on how how closely the ohms rating must match on speakers vs amps; and to what extent it may be causing this 'underpowered' feeling. But all seem to agree '50' on the volume knob should be much louder.

Yes: pre-amp automatically receives firmware upgrade, yes tested with another pre-amp (of sorts) and same response. Amp cannot be 'reset.'

Do I simply need a more powerful or more precisely rated (4 ohm) 5-channel amp? I am stuck with the speakers (which are actually pretty nice in and of themselves) but have an option to switch out the 7055.

Thank you,
Brandon

ps - this 5-ch amp is rated at 4 ohms, but does the higher watt output make it 'too powerful?' (sorry, newbie here)
Model Halo A 51 « Parasound
 
Last edited:
The problem is going to be heat. The lower the Impedance the more current, the more current the more heat. At some point the amp will overheat and shut down.

However, you speakers have pretty good efficiency (Sensitivity rating), and Marantz are generally pretty solid amps. If this had been, for example a Sony AVR, I would say No. But likely the Marantz will not have a problem.

Here is a link to the Marantz AV7704 AVR -

Marantz UK | AV7704

I can't say with certainty that the AVR will work with your speakers, but I can say if you plan to add a Multi-Channel Power Amp, you are going to have to spend a considerable amount of money.

The Parasound A51 5-Channel Power Amp is a considerable £6000 -

Stone Audio - Parasound HALO A51

Steve/bluewizard
 
Thanks Steve.
So, cost aside, it's reasonable to say that Parasound A51 would be a safe bet?

But probably wouldn't want to ever turn the volume up past... 70?

Cheers
 
Thanks Steve.
So, cost aside, it's reasonable to say that Parasound A51 would be a safe bet?

But probably wouldn't want to ever turn the volume up past... 70?

Cheers
It you have £6000, the Parasound A51 would indeed be a very good Power Amp .... if you have £6‚000.

I didn't check, but the AV7704 would need Pre-Amp Outs on all the channels to make this work. Most higher end AVR do have this feature.

But there are others Power Amps -

Marantz MM7055 5-Channel - 140w/ch - £900 -

https://www.hifix.co.uk/home-cinema...s/marantz-mm7055-av-5-channel-power-amplifier

Marantz MM8077 7-Channel - 150w/ch - £1700 -


https://www.hifix.co.uk/home-cinema...s/marantz-mm8077-av-7-channel-power-amplifier

ROTEL RMB1512 - 12-Channel - 100w/ch - £2000 -

Rotel RMB1512 Custom Install Power Amplifier from HiFix

Rotel RMB1575 - 5-Channels - 250w/ch - £1700 -


https://www.hifix.co.uk/home-cinema...mps/rotel-rmb1575-home-cinema-power-amplifier

Yamaha MXA5000 - 11-Channels - 150w/ch - £2200 -

https://www.hifix.co.uk/home-cinema...nel-power-amps/yamaha-mxa5000-power-amplifier

Remember it is not about raw rated power, but about the ability of the Power Supply to back up that power with high current capability.

The Rotel RMB-1575 is likely an amp that can do this. It should have a very strong Power Supply.

Just a few options.

Steve/bluewizard
 
Hi, I actually have the Marantz 7055 already.

As stated in my op, main issue is the Marantz 7055/AV 7704 combo 'should' sound much more powerful than it does driving these speakers. Why doesn't it? Seems I need more power and more importantly, an amp capable of 4 ohm output, to match the speakers'.
 

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