Issue with drivers or cross over

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pmarun

Issue with drivers or cross over
« on: 17 Sep 2012, 12:29 am »
The bass on my 802 matrix IS not enough(for the sake of a better term). The mids and highs are glorious. I bought them used and I think are 12 yrs old. I have read people doing crossover upgrades.  The speakers are in immaculate condition. Would aging crossovers or drivers be the probable  culprits ? Any recommendations on troubleshooting ? I tried a bass test cd from Hsu research. The drivers respond from 20 Hz onwards Appreciate any comments. Thanks

JLM

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Re: Issue with drivers or cross over
« Reply #1 on: 17 Sep 2012, 02:30 am »
A little confused.  Please provide manufacturer's specifications for the 802's.  How exactly did you "try" the bass test.  (Did you have a sound pressure meter?  If so, where did you measure/test from?  What do you mean by "the drivers responded"?)  Bass notes are easily effected by the room size and where you're measuring in the room.

Not knowing the speaker's specs. I'd be impressed if any speaker could do justice to a 20 Hz test tone (without a powered woofer built-in, basically a sub-woofer, or it being a big speaker).  Note that bass reflex (ported) designs often have dramatic frequency loss at low frequencies, but that except for movie sound effects, there's very little content at 20 Hz anyway.

Generally drivers age faster than crossover components, but not always.  Other may have experience with these speakers. 

pmarun

Re: Issue with drivers or cross over
« Reply #2 on: 17 Sep 2012, 12:43 pm »
Now I know why I am classified a newbie.

The Speakers are B&W 802 Matrix S3's. Brochure says "is a 6th order butterworth, gives a fourth order bessel response 9db down at 25 hz"
I played the bass test cd from HSU Research(my sub woofer) and the woofers were vibrating from 20 HZ onwards, slightly audible and the sound increased as the frequency increased. I loaned the CD to a friend so dont have the exact frequency range with me now . Ha, I just picked this of the Hsu Research website. Google, what a wonderful thing.  'Third-octave-wide warble tones, 16-250Hz.

My floor is ceramic tiled without a carpet.

Please see attached pictures.

THanks





srb

Re: Issue with drivers or cross over
« Reply #3 on: 17 Sep 2012, 02:19 pm »
The 802 Matrix is not known for a huge amount of deep bass, but the bass it does produce is tight and solid.  They will produce more bass when directly on the floor and a little less when up on the stands, but again with more clarity.
 
I'm sure you've checked the polarity of the speaker wires, but it wouldn't hurt to verify that the speakers are in phase just in case someone had incorrectly modified the internal wiring or crossovers over the years.  By momentarily connecting a battery to the woofer binding posts you can verify that the woofer cones are moving in the same direction.
 
It also wouldn't hurt to check the tightness of the woofer mounting screws and torque them down if needed.
 
In the end though, it is likely a combination of slightly lean sounding speakers up on stands in combination with the room acoustics.  You wouldn't be the first person that has augmented large "full-range" 802s with a subwoofer.
 
Steve

Letitroll98

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Re: Issue with drivers or cross over
« Reply #4 on: 17 Sep 2012, 04:22 pm »
These are Series 2 specs, a little different, but pretty close.

B & W MATRIX 802 SERIES 2 LOUDSPEAKER SPECIFICATION
Enclosure type: three-way bass reflex
Frequency response: 27-20,000Hz ± 2dB
Drive units: two 200rnin bass, I26mm midrange, 26mm tweeter
Sensitivity: 90dB SPL at 1 metre fort Watt
Power handling: suitable for amplifiers 50-500W
Nominal impedance: 8 Ohms
Crossover frequencies: 400Hz and 3kHz

Here one man's take on crossover rebuild:
http://hifi.goneill.co.nz/bw.php

As noted above, the 802 is known for tight, lean bass, not party house Cerwin Vega bass.  If measuring correctly and testing ok, I would ask what amp are you driving them with.

pmarun

Re: Issue with drivers or cross over
« Reply #5 on: 17 Sep 2012, 09:51 pm »
I use them with a Belle's 150 A Hot Rod Version  125 w/channel into 8 ohms and with an

Opera Consonance Tube Amp

Circuit Type Class A, push-pull amplifier
Power Output 35 watt, RMS 1kHz
Input Sensitivity 220mV
Noise and Hum -90 dB below full output
Frequency Response (-3dB points at 10 watt) 6Hz-50kHz
Tubes 1 ea - ECC83 Input
2 ea - 5687 Driver
2 ea - 5AR4 Rectifier
4 ea - KT88 Output

I feel the same way with both the amp's regarding the bass. I love the mid and the high's. I also live in an apt which does not allow me to play at high levels, often  :).

Thanks

Letitroll98

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Re: Issue with drivers or cross over
« Reply #6 on: 18 Sep 2012, 05:38 am »
You really need to check to see if the speakers are wired in phase.  I know we said the B&Ws are a bit lean, but upon reflection you still shouldn't be missing any bass unless you are a Dr Dre freak.  I use one of the cuts from Stereophile Test CD 1-3 to check speaker phase so have never employed the battery test recommended by srb, but the battery test is an ol' standby.  Or you could just reverse the + and - wires on one speaker and see if the bass returns or goes away more.

charmerci

Re: Issue with drivers or cross over
« Reply #7 on: 18 Sep 2012, 09:43 pm »
Also, a 90db output at 30hz - low frequencies - will not sound as loud as a 90db tone at 4000hz. The human ear is more sensitive to certain frequencies than others. (Can't remember the name of the chart/graph that shows this.)

Letitroll98

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Re: Issue with drivers or cross over
« Reply #8 on: 18 Sep 2012, 10:46 pm »
So right, you can see this on the Rat Shack SPL meter or even with your smart phone app.  I kinda like my Android spectrum analyzer and sound level meter.  I don't suppose it's very accurate and I wouldn't think of even recording the measurements, but for a quick snapshot it works surprisingly well, especially for free.

Anyway, I agree, you can't play a test tone and just listen, you need some type of measurement tool, especially in the bass and high treble. 

Oh, BTW, it's the Fletcher-Munson equal loudness curve.  I believe it's been updated with modern data.

charmerci

Re: Issue with drivers or cross over
« Reply #9 on: 19 Sep 2012, 05:16 am »
Also, they were designed as floorstanders. Get them off the stands.

pmarun

Re: Issue with drivers or cross over
« Reply #10 on: 23 Sep 2012, 01:11 pm »
Thank you for your comments.

I have been doing some listeningthis week. I mostly listen to classical music. Today listening to favorite encores, Chandon collect, at volume level 7 on my ar preamp(usually set it at 4) I felt no loss of bass. This thread was initiated after I listened to some tub thumping party music at a friends. Seems like it is the effect of diferrence kinds of music.

So one of my speakers is currently connected out of phase, but still sitting on the stands(am not too sure I trust the original screw on spikes supplied). Sounds good now, looking to add some carpeting and also try out some better spikes. The Android spectrum analyzer will also be a good experiment.

Thanks again everybody I will log my findings as I keep trying to get the best from what I have.

Rgds

Letitroll98

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Re: Issue with drivers or cross over
« Reply #11 on: 23 Sep 2012, 03:13 pm »
So one of my speakers is currently connected out of phase, but still sitting on the stands....

 :o

Either you didn't understand the post or misspoke on this one.  Both speakers need to be in phase for proper bass response.

The stands are just fine and are highly recommended by many users to get the 802's at the proper height.

Don't listen to party music at friends houses, get new friends.

pmarun

Re: Issue with drivers or cross over
« Reply #12 on: 24 Sep 2012, 12:45 am »
Last week when i changed from the opera to the belles amp I inadvertantly connected one of the speakers out of phase. Was listening in that mode the whole of last week  I found out yesterday corrected it and did not find a big diferrence.  I was listening to track.9 solitude on the favourite encores cd and.could'nt  wait to back to it. Connected it out of phase again and went back to my listening. I think I must be making some basic mistake. Have to get back to it.

I got the stands separately, and they have improved the resolution of the speakers.  And yes all setup of this speakers I have seen has been on these stands. I think they were built specifically for this model.

Have to thank my buddy, got me back into the tweaking. I appreciate the audio circle community really adds another dimension - the people, into this hobby. Have a great  week ahead.
Rgds.

Letitroll98

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Re: Issue with drivers or cross over
« Reply #13 on: 24 Sep 2012, 03:36 pm »
Last week when i changed from the opera to the belles amp I inadvertantly connected one of the speakers out of phase. Was listening in that mode the whole of last week  I found out yesterday corrected it and did not find a big diferrence.  I was listening to track.9 solitude on the favourite encores cd and.could'nt  wait to back to it. Connected it out of phase again and went back to my listening. I think I must be making some basic mistake. Have to get back to it.

I got the stands separately, and they have improved the resolution of the speakers.  And yes all setup of this speakers I have seen has been on these stands. I think they were built specifically for this model.

Yes, you are correct, you're making a fundamental error somewhere.  Or basic as you say, which is what you should do.  Get back to basics and make sure of your connections and setup.  It's not in reworking your crossover or eliminating the stands, it's something simple.  You should be hearing a marked difference in bass output in the room between in phase and out of phase hookup.