Amp for B&W Matrix 803 S2

Hi Alex.

3.5 x 5 meters so about 11.5 x 16.5 feet.

thx for linking a diagram. I updated it
here for reference.

Is this a shared space with restrictions on placement or are you able to set up the speakers shooting down the long wall ?
for this my updates - the gold dots show the speakers, blue dot yourself.
The first reflections are very important with this speaker. And unlike the 802 and 801 the 803 tweeter and midrange are not on pods.adjustable.
If you find the sound too direct, in your face, due to room reflections rotating the pods slightly out corrects this. with the 803 the whole speaker needs to be turned.
If you need to keep the speakers as in your original diagram (red/green dots) then I recommend a first reflection point for the right speaker. A portable free standing wall.

sort of like this just to give you an idea.

The yellow line in the diagram is this wall. There is a simple technique to find the spot to place this portable wall using a mirror and one friend.
I can detail if you like. Shooting down the long side avoids having to do this.


Re: your comment:

Regarding BAF filters. It's very contradictory information in the Internet. Someone says that they aren't necessary for 803 S2. Anyway I guess it's not easy to find them nowadays especially here in Russia...

I really like that you used the word contradictory. It is a very good word for this audio hobby which IMO can be very contradictory at the best of times. :^)
You know what they say - Ask 12 audiophiles for an opinion and you will get 16 opinions back ...something like that.

Something to consider

I took a few minutes and read Doug Schneider's 803 review for Soundstage that I linked. Not once did he mention the BAF. This makes one assume he did not use one. From the review.
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"Although literature claims response down in the 28 hz range, I'm not doing much better than 50 in my room. In addition, they 'hump' a bit at 80 hz, but this probably has more to do with the room that anything since.....

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This is very accurate going by memory now from my experience.
He is not hearing 28 hz because it is down 6 db compared to the remaining frequencies without the BAF.
The 80-100 hz frequencies are also obscuring the lowest octave information. He is missing the whole bottom octave for this review,
he really liked the speakers, but imagine how the review would have went if he heard the bottom octave.
The BAF, it's an equalizer (booster) and makes the amp work for the lowest octave.
You can't cheat Physics. In compromised spaces and using smaller speaker box design, like the 803, the BAF makes the speaker fuller range.
Each 800 series matrix speaker has a different setting with it.

Now I am pretty sure that those that say they do not use it are either;

1) just using subs instead set at 50hz and down
2) using another external equalizer of some kind
3) tone controls for bass and treble.
3) are just happy with bass to 50 hz.

Hey - as long as they are happy. Cool.

But no one knew these speakers better than B&W designers, testers.

As far as amps go.... Do you want the setup to work ok, or do you want it to sound really good from the get go.
Are tube amps out ?
You need to hear the amp/s in your room. Avoid buying unheard - especially used SS amps which may need capacitors changed out and other work.

What are you using for a preamp ? is it Solid State ?

Holy moly - so many questions :^)

Anyway, a few more thoughts for you to consider ....
fun stuff.... keep it fun..

Unfortunately there are not much variants where to put the ACs... On the left side it's a passage to other rooms so the only possible option is the put them on the opposite side of the room. Maybe it's a good idea as I'm going to remove the left wall so in this case I can put the ACs further from each other.
Here is how it looks now:
https://lh3.googleusercontent.com/-DHshSKeisfE/VVL9RR6-ABI/AAAAAAAAHUc/coZlZNgrV-0/w732-h412-no/20150508_181419.jpg

Regarding my system. The purchase of Matrix was very unexpected... As a temporary solution I have a very old Pioneer reciever which I used as DAC/Amp. Several years ago I converted all my CDs to lossless flac so my idea is to use PC and good professional audio card as DAC.

some thoughts
Your open doorway is a wild card and provides for bass leakage. The doorway makes for a bigger room as far as the speakers sound waves are concerned.
Only in this hobby can "leakage" be a good thing. I guess depending on who is hearing the leakage (wife?)

If you leave things as they are, one idea; you will get improvement by putting in a sliding curtain behind the speakers, in front of the TV. The curtain will open from the middle out to the ends. Close it to listen to 2 channel music covering the TV and providing damping for the speakers. Open up from the middle when the TV is in use - but leave closed behind the speakers. Also I can't see to the left of the sofa but treatment on that back wall with a panel or thick curtain will absorb bass waves; allowing you to be play music at higher spl levels and the sound will be better defined.

If your only limitation for speaker placement experiments is the AC outlets/wall modifications, and it is
1) not an apartment with landlord who doesn't want you making holes in the wall or
2) a wife acceptance thing; then I would experiment.

For one test you could borrow a thick 10 gauge extension cord for your amp/receiver and DAC and temporarily place speakers at both ends shooting down the room. This will allow you to experience the room effects with the speakers. You can then decide if it is worth it to you to modify the AC locations to accommodate this.

So finally my Luxman M600A is here. Sounds good especially for such price) Now it's time to think about preamp and DAC. The very first option is Luxman C600F and Aqua La Scala Mk II DAC...

Do yourself a favor and get a Pass Labs class A/B model. I have the x250.5 and it drives my Matrix 803 series II with aplomb. I've owned these speakers for 20 years (since they were new) and they sound the best with this amp. I also have the full class A 60 wpc model Aleph 5 and it just doesn't control the woofers as well as the class AB model does. If you are looking for something less expensive than Pass, I personally would take a long look at the Parasound Halo A21, which is also a high bias class AB design and could be considered a "poor man's" x250.5. Good luck and enjoy!