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Upgraded from B&W 805 Matrix to 802 Matrix S3, and have some questions...

68.118.28.250
Posted on May 11, 2017 at 09:51:59
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 I'll go ahead and sound like a complete "newbie" here, but I can't find any solid answers.

First question - the nominal impedance of the speakers as a whole:

B&W's owner's manual for the 802 M S2 says: "Nominal 8 Ohm, not falling below 4 Ohm." Their manual for the 802 M S3 says: "Nominal 4 Ohm." Yet? My speakers themselves state 8 Ohm right on the back. Anybody have an impedance curve for the system as a whole?

Second question - if I want to biamp? What kind of impedance are we talking for the treble/mid unit, and for the bass bin? Schematics I see show them being in parallel if the system is run with a single amp/cable - which would suggest they are individually at least 8 ohms...

Not really worth talking about what I'm driving them with - they are in my home system, which is nothing special. But? They are quite a nice step up from the 805 Matrix that they have replaced.

 

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RE: Upgraded from B&W 805 Matrix to 802 Matrix S3, and have some questions..., posted on May 11, 2017 at 13:05:47
John Elison
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  Since: January 29, 2004
 The solid black line is the impedance curve of the N802D, which is similar to the 802 Matrix S3. It looks like a roller coaster to me.


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Here is the actual impedance curve of the 802 Matrix S3 from a review by Ken Rockwell. The green line is impedance and the yellow line is phase.

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I prefer a flatter impedance curve. My Thiel CS3.7 speakers have an impedance curve that is very flat at 3-ohms +/-0.5-ohms from 60-Hz to 24-kHz.

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My Own Measurement


 

Appreciate the info, but have pretty much entirely dismissed that page, posted on May 11, 2017 at 14:48:57
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 His graph of impedance and phase angle may be accurate, though I doubt it - as the $Phile plots for the 801 Matrix S2 don't even hit a low of 5 Ohms.

My reason for discounting the page lies in most everything towards the bottom of the page, including where he notes:

"6.13 ohms 50-3k" which, SORTA corresponds to the Stereophile measurements of the 801, except, as you've noted - the impedance isn't particularly flat.

Me? I don't need my impedance to be flat - all I care about are maxes, mins, and a nice flat and/or predictable output when driven by a known amplifier. :)


 

RE: Appreciate the info, but have pretty much entirely dismissed that page, posted on May 11, 2017 at 15:20:45
John Elison
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Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 The 801 is a different speaker. The 802 has a minimum impedance of 3.4-ohms according the B&W spec sheet for the Matrix 802 Series 3.

However, it's pretty easy to measure impedance. I measured my Thiel CS3.7 and my measurement was identical to the impedance curve published by Stereophile.



 

FWIW, posted on May 11, 2017 at 15:26:14
E-Stat
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  Since: April 5, 2002
 I don't need my impedance to be flat...

It is pretty important for neutral response when you're using highish source impedance tube amps - like me. :)

 

I'll buy that. But? Their spec sheet still contradicts their owner's manual..., posted on May 12, 2017 at 07:38:25
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000



I just don't like conflicting info - especially when released by an "official source," such as the actual manufacturer.

And, yeah, the 801 is a different speaker - except for the fact that the mid/tweeter section is exactly the same as in the 802. Haven't checked the schematic on the 801 vs 802, but I believe the upper range crossover may be the same as well.

 

Well, that's for sure!, posted on May 12, 2017 at 07:46:40
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 If you choose a system based on the amp, the speaker better be a good match.

Same goes in reverse - if you choose a speaker with certain characteristics, it might well eliminate some amplifiers as a reasonable choice. :)

 

I think you're best bet is to measure your speaker's impedance..., posted on May 12, 2017 at 09:20:36
John Elison
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Posts: 23900
Location: Central Kentucky
Joined: December 20, 2000
Contributor
  Since: January 29, 2004
 Check the link below to find out how I measured mine.

 

I know what you mean..., posted on May 12, 2017 at 09:58:26
kootenay
Audiophile

Posts: 8446
Location: Calgary, Alberta
Joined: October 16, 2007
 When I had the 802 S2 it had the 8 ohms impedance on it as well. However, it sounded much better when I had them connected to the 4-ohm tap of my then Audio Research D-250 tube amp. I didn't need to bi-amp them as the Audio Research had enough power to make them sing properly. Although the bass response could be a little bit deeper, perhaps using the BAF would have help in this regards, but at the expense of the overall sound quality.

Fast forward, I got rid of the 802 and bought the 801 S3, which I thought had a more visceral presence and well-balanced sound from top to bottom. Although they sounded similar in the upper range, but 801 surpasses the 802 in the bottom end where it went down deeper, delineated and very articulate. Also, I'm not bi-amping them as the Krell power amp that I'm using has more than enough power to make them sing properly without worrying about their swinging impedance.


 

Sixth order Butterworth filter?, posted on May 12, 2017 at 10:03:32
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Wow, that's a little heavy handed there! That would put the full range guys in a tail spin.

When ever I see filters of that magnitude usually it's "not a good thing".

 

You probably didn't notice..., posted on May 12, 2017 at 10:26:34
kootenay
Audiophile

Posts: 8446
Location: Calgary, Alberta
Joined: October 16, 2007
 * sign on the specs where it stated that the speakers can only achieve this frequency response if you buy the optional external filter. This external filter gives the possibility of extending the response down to 25Hz(-3dB point) using the 6th order Butterworth alignment. This will also filter out the unwanted subsonic frequencies, which may introduce the intermodulation distortion (according to the manual).

If you look at the spec again and read it you'd notice that the speaker main crossover network that is being used is the 4th order Butterworth network.

 

Isn't that "4th order Bessel" w/o and "6th order Butterworth" w/(active) BAF? (nt), posted on May 12, 2017 at 10:47:15
Steve O
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Posts: 12381
Location: SE MI
Joined: September 6, 2001

 

Not according to the..., posted on May 12, 2017 at 11:20:33
kootenay
Audiophile

Posts: 8446
Location: Calgary, Alberta
Joined: October 16, 2007

802 S3 specs found in the manual. It is 4th order Butterworth crossover network.

 

RE: Well, that's for sure!, posted on May 12, 2017 at 11:50:45
E-Stat
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Contributor
  Since: April 5, 2002
 My long term fondness for electrostats with their cranky reactive load has always steered my choice of suitable amplifiers.

Threshold and VTL have served me well for decades. :)

 

Spec inconsistencies..., posted on May 12, 2017 at 12:29:30
Steve O
Audiophile

Posts: 12381
Location: SE MI
Joined: September 6, 2001
 ...the 801M Series II spec states exactly as what you posted regarding crossover alignments. However...........in the discussion section of the 801 users manual preceding spec tabulation: "It should be noted that the loudspeaker may be used perfectly satisfactory without this additional [BAF] filter giving the system a fourth order Bessel alignment." In the case of the 801, the BAF is actually a S&K 2nd order HP filter with fc~20Hz and Q=2. All this is consistent with 4th order Bessel w/o BAF and 6th order Butterworth w/BAF. I assume, maybe incorrectly, that the 802 is same basic design w/diff fc.

 

As for VTL?, posted on May 12, 2017 at 15:17:58
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 Have a VTL Ultimate pre feeding Deluxe 120 mono amps that drive a pair of Gallo Nuc Ref 3s at the shop.

Yeah - that setup WORKS! :)

 

You're absolutely correct, posted on May 12, 2017 at 15:23:42
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 Without the add on BAF, it is a 4th order Bessel.

My reason for posting was the glaring inconsistencies between Users Manuals, Spec Sheets, back of speaker markings, and everything else.

The B&W 801 & 802 Matrix (of various iterations) are/were some of the most widespread loudspeakers on the planet in recording studios & other technical environments. You would ALMOST think that solid data & measurements for every possible configuration would be reliably available on the internet.

 

Yes, given B&W's breadth and depth you should be safe in assuming all that..., posted on May 12, 2017 at 16:02:09
Steve O
Audiophile

Posts: 12381
Location: SE MI
Joined: September 6, 2001
 ...OTOH, the Internet is much overrated.

 

AND, that's why I won't publish MY measurements..., posted on May 14, 2017 at 08:57:28
David S.
Audiophile

Posts: 3552
Location: Mountains of WNC
Joined: August 31, 2000
 Yes, they are reasonably accurate, but using a CD of various test tones & sweeps, and a crapload of alligator clips, and resistors that haven't been officially "calibrated," and mediocre multimeters, and...

Yeah - simple measurements & actual hookups/cable swapping confirm that in my particular setup, using the A&B front speaker connections to bi-amp the B&W 802 Matrix S3 (with the "A" outputs driving the mid/tweeter terminals, and the "B" outputs driving the bass terminals) not only sounds better, but is also the most stable connection (as also verified by the manufacturer of the POS (well, not THAT bad) receiver that I am driving them with.

 

RE: AND, that's why I won't publish MY measurements..., posted on May 15, 2017 at 07:24:27
airtime
Audiophile

Posts: 11287
Location: Arizona
Joined: February 4, 2003
 Hey, speakers are like sausage making. If it sounds good don't ask how it's made. Just enjoy them.

 

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