Denon X4700H paired with B&W 703 - Do I need a power amp?

tekken57

Novice Member
Good afternoon all. I've recently begun the journey into high end audio and I require some advice.

Over the past few years, I've been slowly upgrading my AV equipment piece by piece and I am currently using the following setup:
Denon X4700H receiver
Bowers and Wilkins 703 S2 fronts
Bowers and Wilkins 706 S2 as side surrounds
Bowers and Wilkins HTM 71 center
Bowers and Wilkins CCM683 in ceiling speakers as my rear surrounds / Atmos speakers
Acoustic Research Sub (Haven't upgraded this as yet)

As I am musician, my room has quite a bit of acoustic treatments applied. I sometimes use the same room to record vocals, so I've spent quite a bit of time trying to reduce the reflections in the room using acoustic panels.

I use the receiver to listen to both music as well as watching movies equally. When listening to music, I prefer listening in multichannel audio mode as I find this to be the most immersive experience for me.

My question is should I add a power amp to my setup to power the 703's? The reason why I ask is because whilst the sound is very good at present, it seems like the 703's aren't really getting much of a workout. I also need to set the volume to about 60%-70% on the avr for the speakers to really come to life.

With current rate of exchange here in South Africa, AV equipment is quite expensive and I usually upgrade one item a year. That being said, I am getting quite a good deal on used Rotel 1582 MK2 power amp which is rated at 200W x2. We don't have the option to try out equipment on loan here in SA, so I'd like to get some opinions on this pairing.

Lastly, I've been through these forums, the AVR manual and YouTube videos to get information on how to connect a power amp to the 4700H. It seems like there are three options:

1. Set the AVR to pre out, however this turns off all the amplifiers on all channels which won't work for me as I only want to drive the fronts with the power amp.
2. Set the AVR to 11 channel mode and set the pre out to the power amp. However I only have a total of seven speakers so I'm not sure how this would work as the AVR is expecting 9 speakers on the 11 channel mode.
3. Leave the AVR as is and connect the power amp through the pre outs. I've read that this option runs the pre outs in parallel to the front amps, causing some distortion at 1.4v. I'm not sure what this means as it's the first time I'll be using a power amp. Will this connection cause issues with the Rotel 1582?

Thank you for reading my post, I know it's quite long but I figure the more information I can provide the better.
 

gibbsy

Moderator
Welcome to the Forum.

With the number and type of speakers that the Denon is driving I would say that, unless your room is very big, there is sufficient power available. The easiest way to check the levels you are listening to is to change the volume setting from the absolute range to the dB range.

Doing so will give the dB level that you are listening at. 60-70% on the absolute scale would be around the -15 to -20dB, ie you are listening at 55 to 60dB. Given those numbers the Denon has plenty of power in reserve as it can push to +18dB giving you 93dB at the MLP.


Adding a power amp is easy. Set to 11.1 and use whatever pre-outs you need. The connected pre-outs will be confirmed on the on screen graphics with the suffix Pre shown above those connected speakers. Just run Audyssey to EQ the amp into the system.

Volume​


Set the MAIN ZONE (room where the unit is located) volume setting.

Scale​

Set how volume is displayed.
0 - 98
(Default):
Display in the range 0 (Min) to 98.
-79.5 dB - 18.0 dB:Display ---dB (Min), in the range –79.5 dB to 18.0 dB.
 

gibbsy

Moderator
2. Set the AVR to 11 channel mode and set the pre out to the power amp. However I only have a total of seven speakers so I'm not sure how this would work as the AVR is expecting 9 speakers on the 11 channel mode.

You should already have confirmed on setting up what speakers you have connected.
 

rccarguy2

Distinguished Member
With 1.4V max voltage from the Denon you'll get 100W from a power amplifier with 26dB gain. Use this guide. Not ideal with that Rotel.


As for the Denon feature of pre amp mode, it doesn't "shut off" the amplifiers, they're still on and active, it's just the signal to the amplifiers are switched off.

I'd look for a power amplifier with 29dB gain /lower sensitivity level.
 

tekken57

Novice Member
Welcome to the Forum.

With the number and type of speakers that the Denon is driving I would say that, unless your room is very big, there is sufficient power available. The easiest way to check the levels you are listening to is to change the volume setting from the absolute range to the dB range.

Doing so will give the dB level that you are listening at. 60-70% on the absolute scale would be around the -15 to -20dB, ie you are listening at 55 to 60dB. Given those numbers the Denon has plenty of power in reserve as it can push to +18dB giving you 93dB at the MLP.


Adding a power amp is easy. Set to 11.1 and use whatever pre-outs you need. The connected pre-outs will be confirmed on the on screen graphics with the suffix Pre shown above those connected speakers. Just run Audyssey to EQ the amp into the system.

Volume​


Set the MAIN ZONE (room where the unit is located) volume setting.

Scale​

Set how volume is displayed.
0 - 98
(Default):
Display in the range 0 (Min) to 98.
-79.5 dB - 18.0 dB:Display ---dB (Min), in the range –79.5 dB to 18.0 dB.
Thank you for your response. I'm happy to get an honest response as most stores here are insistent that I get a power amp due to my AVR is not powerful enough to drive the 703's. Considering that I am not able to audition powers amps here, I couldn't verify these claims.

My room size is 6.6 meters x 6.5 meters. I have set the volume to db range as suggested and my listening level are around -24db to -22db on this scale.

I have also confirmed that on 11 channel mode I can set the fonts to pre out's and then turn off the unused speaker assignments in other menus.
With 1.4V max voltage from the Denon you'll get 100W from a power amplifier with 26dB gain. Use this guide. Not ideal with that Rotel.


As for the Denon feature of pre amp mode, it doesn't "shut off" the amplifiers, they're still on and active, it's just the signal to the amplifiers are switched off.

I'd look for a power amplifier with 29dB gain /lower sensitivity level.
Thank you for pointing me to this table. I didn't understand what the 1.4 v value meant before this.

However my confusion arose from reading the information in this thread: Denon X4700H pre-out configuration options?

And this review:

Basically I couldn't figure out if the 1.4v limitation applied as I planned to run the front speakers in the 11 channel pre out mode. The information posted in the other threads stated that in pre out mode the AVR is stable at 1.8-2v, which is why I thought the Rotel would work despite it's sensitivity being 1.9v with a 26.5dB gain?
 

two2midnight

Distinguished Member
Thank you for your response. I'm happy to get an honest response as most stores here are insistent that I get a power amp due to my AVR is not powerful enough to drive the 703's. Considering that I am not able to audition powers amps here, I couldn't verify these claims.

My room size is 6.6 meters x 6.5 meters. I have set the volume to db range as suggested and my listening level are around -24db to -22db on this scale.

I have also confirmed that on 11 channel mode I can set the fonts to pre out's and then turn off the unused speaker assignments in other menus.

Thank you for pointing me to this table. I didn't understand what the 1.4 v value meant before this.

However my confusion arose from reading the information in this thread: Denon X4700H pre-out configuration options?

And this review:

Basically I couldn't figure out if the 1.4v limitation applied as I planned to run the front speakers in the 11 channel pre out mode. The information posted in the other threads stated that in pre out mode the AVR is stable at 1.8-2v, which is why I thought the Rotel would work despite it's sensitivity being 1.9v with a 26.5dB gain?
The ASR graphs show a drop in sinad from the max 101db at 1.1V down to around 97db at 2V output with the front two amps 'off'. That is still better than many other AVRs manage at 2V which you can see by looking at the sinad comparison figures. As such I wouldn't bother too much about using nearer the 2V output level if necessary.

Best AVR DAC Performance Measurements.png


However if you were using 3 channels+ (unless in pre-amp mode with all amps 'off') you would run into the clipping results of 70db sinad at 2V which is poor.
 
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gibbsy

Moderator
Thank you for your response. I'm happy to get an honest response as most stores here are insistent that I get a power amp due to my AVR is not powerful enough to drive the 703's. Considering that I am not able to audition powers amps here, I couldn't verify these claims.
Your speakers are 89dB sensitive and have a drop to 3.1 ohms. If you have a subwoofer then the low end on the fronts should be no lower than 80hz. You don't really need a power amp. Having a power amp will bring benefits as your taxing the Denon less certainly when you add a full complement of speakers. Apart from some extra headroom, a power amp will not improve the actual audio.

I'm driving speakers that are not to sensitive as your with the same kind of drop. I'm listening at a higher level in a room of equal size, give or take, and return the same figures on the dB scale and my X6500 is a more powerful unit.

If you use the Denon for stereo music then I would suggest a quality stereo amp with HT by-pass and all music sources running through that. The stereo amp would then act as a power amp for the 703s and this combination would bring improvements for music.
 

tekken57

Novice Member
The ASR graphs show a drop in sinad from the max 101db at 1.1V down to around 97db at 2V output with the front two amps 'off'. That is still better than many other AVRs manage at 2V which you can see by looking at the sinad comparison figures. As such I wouldn't bother too much about using nearer the 2V output level if necessary.

However if you were using 3 channels+ (unless in pre-amp mode with all amps 'off') you would run into the clipping results of 70db sinad at 2V which is poor.

Thank you for explaining, that clears up my confusion.

Your speakers are 89dB sensitive and have a drop to 3.1 ohms. If you have a subwoofer then the low end on the fronts should be no lower than 80hz. You don't really need a power amp. Having a power amp will bring benefits as your taxing the Denon less certainly when you add a full complement of speakers. Apart from some extra headroom, a power amp will not improve the actual audio.

I'm driving speakers that are not to sensitive as your with the same kind of drop. I'm listening at a higher level in a room of equal size, give or take, and return the same figures on the dB scale and my X6500 is a more powerful unit.

If you use the Denon for stereo music then I would suggest a quality stereo amp with HT by-pass and all music sources running through that. The stereo amp would then act as a power amp for the 703s and this combination would bring improvements for music.

To provide an update, the retailer has allowed me to try the Rotel unit out at home for a week. I was concerned that something could have been damaged as the unit was second hand, which is why they allowed me to test it.

After hooking the power amp up to the AVR, I immediately noticed a significant different in the sound quality. The level of detail that I am getting out of the B&W 703's seems to be a lot better and more "clear" for the lack of a better word.

I am also noticing that I am getting much better performance at lower listening levels. I am now listening at -39db to -30db levels which is in the comfortable to loud range for me. The 703's seem to come to life at a much lower listening level now as well.

I wanted to provide some detail on others wanting to use this particular setup on the avr. I set the avr to 11 channel mode with front Dolby speakers, rear surrounds and rear height speakers even though I am only using 7 speakers in total. This was the only way in which I could assign the front speakers to pre-outs in this configuration.

I then went into amp assign and turned off the Dolby front speakers. However there is a limitation here, I am using rear in-ceiling speakers and I was not able to leave these on with the Dolby front speakers turned off. I was only able to assign these speakers to rear surrounds, not to height surrounds. Not sure if that makes any difference with Atmos audio?

Secondly after running the Audyssey setup, I was getting a lot of distortion on the 706's I am using as side surrounds when playing bass heavy tracks. Checking the amp assign again after the Audyssey setup, resulted in these speakers being set to large by Audyssey even though I had set these to small prior to setup. Remember to always check your speaker assignments after running Audyssey before playing at high volumes.

Audyssey also set the crossover levels to 40hz for all speakers which I changed to 80hz as it sounded better to me with my sub turned on. That being said, I also feel like I need to upgrade my sub at a later stage as it seems like the sub doesn't seem to respond "fast enough" in comparison to the 703's if that makes sense. I'm thinking of maybe getting the SVS PB 1000's next year.

The Audyssey setup also seems to push the high ends a bit too much for my tastes. This was present when using the AVR on it's own as well as the AVR with a power amp. Using the manual EQ kind of resolves this issue but still doesn't sound as good as the automated setup, I'm assuming because it doesn't apply the room corrections. However, I also assume that this is what the Audyssey paid app is for (adjusting the curve)?


I've yet to setup the power amp for cinema viewing, so I can't comment on this as yet. I usually set up a second preset on the Denon for cinema whereby I set all the speakers to small and then run Audyssey. I also set the sub to LFE only, reduce the sub level and increase the center channel level for this preset

I'm not certain if I'm going to keep the power amp as yet, I'm going to use it for a few more days before deciding. I never listen to stereo recordings anymore as I moved away from physical media years ago, with the exception of Blu Ray music concerts. I'm streaming music though Tidal via airplay through the Denon or using an Xbox Series X for physical media and video streaming. So in that regard the AVR + power amp meets my requirements.

I'm still on the fence as the sound was pretty good with just the AVR. With the addition of the power amp the overall experience is just a bit more refined. However considering that the retailer is offering me a price which is 1/3 the price of new Rotel unit, the amp is looking quite tempting.
 

rccarguy2

Distinguished Member
How about two of these better value than svs



-39 is not loud that's background level or even lower than that. I'd do a manual level calibration with a meter.

Also does the Xbox pass all formats? I read somewhere it doesn't, Atmos DTS:X maybe?

Have a play with the app and try setting the room correction cut off at 300hz
 
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rccarguy2

Distinguished Member
Monoprice subs prices go back up
 

N1ck

Active Member
The SVS pb1000 is £450 plus you get a 5 year warranty which is one of the best in the business plus you can buy in the UK. I don’t see the value in the Monoprice anymore.
 

tekken57

Novice Member
How about two of these better value than svs



-39 is not loud that's background level or even lower than that. I'd do a manual level calibration with a meter.

Also does the Xbox pass all formats? I read somewhere it doesn't, Atmos DTS:X maybe?

Have a play with the app and try setting the room correction cut off at 300hz

That's actually a really good recommendation. I've never heard of Monlith before, however after searching it's like there a no local distributors here in South Africa. The cost of import these subs myself, pushes the value above that of the SVS PB 1000.

The Xbox has a passthrough option which each individual app can take advantage off or process the audio on the Xbox itself. Both Atmos and DTS:X are supported however you need to pay for the DTS codec, so I don't use this. The movies and tv plays media files with Atmos and HDR without issue. Same goes for the Netflix app.

An update on the power amp. I've run a second Audyssey setup for preset which I use for cinema viewing i.e I usually set the sub to LFE only, increase the center channel volume and use the Dolby Atmos option instead of Multi Channel Stereo on this.

Honestly, when viewing movies on this preset, there no difference / very negligible difference when using the power + AVR vs using just the AVR. I think this is because the center channel is mainly listened + used for dialog for the majority of most movies and this channel is still powered by the AVR in both scenarios.

However as I mentioned before, the performance when listening to music in both multichannel stereo and 2 channel stereo modes is better in my opinion. The AVR also performs better at lower volumes when using the power amp, with the remaining speakers powered by AVR sounding better as well.

So after using the power amp for a week now and taking into consideration the excellent price the store is offering me, I've opted to keep the power amp.

Thank you for all the comments and guidance in this thread. I hope my experience will help others facing a similar decision.
 

weezy40

Standard Member
My two cents:

I just upgraded my MARANTZ SR6008 with a 5 channel parasound 85 Watts rms per channel external amp

I was really on the fence wether this would make a difference, but I got a very good deal on a second hand one and hearing it in my 5.1 setup it really closes the debate for me.

World of difference, uncomparable. Much more sepration in the different sound effecst, much more detail overall but expecially in the mid and low and even on loud volumes so much cleaner and more engaging sound.

In big scenes with explosions and what not it is not a very loud emulsion but just more controlled and separated. Won't fatigue you as much as the sr6008 does on its own.

I read a lot about hoe separates have more real hifi power as they do not need to share with processing and fit in a tight cabinet etc and I am super happy to report that in my experience it is true.
 

rccarguy2

Distinguished Member
My two cents:

I just upgraded my MARANTZ SR6008 with a 5 channel parasound 85 Watts rms per channel external amp

I was really on the fence wether this would make a difference, but I got a very good deal on a second hand one and hearing it in my 5.1 setup it really closes the debate for me.

World of difference, uncomparable. Much more sepration in the different sound effecst, much more detail overall but expecially in the mid and low and even on loud volumes so much cleaner and more engaging sound.

In big scenes with explosions and what not it is not a very loud emulsion but just more controlled and separated. Won't fatigue you as much as the sr6008 does on its own.

I read a lot about hoe separates have more real hifi power as they do not need to share with processing and fit in a tight cabinet etc and I am super happy to report that in my experience it is true.

This is the older version of yours 66w with 7ch

So it's only bit more powerful but I do think it's control of the speaker, I have 60w amps and they sound far better than the built in avr amp stages of a avr I used to have.

You'd find the PSU and capacitor storage in that parasound to be multiples of that marantz.
 

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