B&W P6 sound DEAD compaired to 705s?

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  • junior77blue
    Senior Member
    • Nov 2004
    • 635

    B&W P6 sound DEAD compaired to 705s?

    I have an older pair of B&W P6 speakers....purchased them new approximately in ~1997. They have been used in numerous applications, HT & stereo.

    After I purchased my 705's...the P6s just sound DEAD. Midrange and tweeters sound lifeless. I had the tweeters replaced, but that didn't change the sound.

    What I'm wondering is if the 705's are THAT much better of a speaker or if something is drastically wrong with my P6 series speakers, i.e., crossover or midrange.

    I'm by no means an 'audiophile', I just know what sounds good to me.

    Is there anything I can do to physically check to determine what, if anything is wrong? i.e. resistance? Or do speakers age that much over time and this sound should be expected? Would it be cost effective to replace drivers/cross-over?

    Shoot, I have a pair of Paradigm 7s that sound better than my P6's!!

    I'm currently using an older Adcom Amp GFA-5400 to drive these towers.

    Any input/insight would be greatly appreciated...
  • Aussie Geoff
    Super Senior Member
    • Oct 2003
    • 1914

    #2
    Junior77Blue,

    Speaker Technology has improved a fair bit but the B&W P6s were excellent speakers for their day - comparable to todays 704/703 series in B&Ws range...

    I'd expect the 700 series to sound quite a bit better (3 generations of improvement) but not enough to make the P6 sound "dead". One (quite likely) posibility is that the capacitors in the crossover have aged out of tollerance. Take them into your B&W dealer to listen on his amplifiers - he will be able to tell you straight away if they sound normal. If not B&W have a excellent repair service and will have them "as good as new" in a week or two (depending upon how far it is to the nearest authorised repairer). If they do sound much better at the dealers you could have a problem with your older Adcom amplifier (any ampliifer with negative feedback can age to the point where you get flat lifeles sound!)

    Geoff

    Comment

    • junior77blue
      Senior Member
      • Nov 2004
      • 635

      #3
      Can you commet or clarify what 'negative' feedback means? What amps don't have negative feedback?

      I've tried the speakers on a couple of different HT recievers as well....same result, so I don't think it is the electronics but good to learn about amps 'aging'.

      I thinking the same thing your thinking...it has to be in the crossovers. I plan on bringing them to the shop tommorow.

      Comment

      • Aussie Geoff
        Super Senior Member
        • Oct 2003
        • 1914

        #4
        Junior77Blue,

        Negative feedback is a very very common design technique, especially in transistor amplifiers where the output signal is compared to the input signal and the diffrence reverses and sent back to the input, so that it is adjusted to be much closer than the original sound... Bottom line is it reduces distortion...

        Geoff

        Comment

        • junior77blue
          Senior Member
          • Nov 2004
          • 635

          #5
          And over time this 'ages' or doesn't work as properly? What's the typical 'life' ...any ideas?

          Comment

          • Aussie Geoff
            Super Senior Member
            • Oct 2003
            • 1914

            #6
            Junior77Blue,

            There are 5-6 different capacitor technologies and within those different manufacuring qualities + Batch variances. Most electolics, oil or wax capcitors will last 10 to 20 years - thouse some (especially oil and wax) will fade out after 7-10 years

            Take it in the store should know in a few minutes...

            Geoff

            Comment

            • junior77blue
              Senior Member
              • Nov 2004
              • 635

              #7
              Thanks, I appreciate the help...

              Comment

              • Aussie Geoff
                Super Senior Member
                • Oct 2003
                • 1914

                #8
                Junior77Blue,

                One further thought. An acquaintance of mine with the P5s mentioned that he had found the treble deteriorating compromising the whole sound stage. The tweeter cones were replaced and this did not really correct the problem. After some investigation it was determined that the problem was that the Ferro-fluid used in the tweeters had become thick (treacle like) due to age and absorbing the glue from the tweeters construction. Contact with B&W revealed that this was a known fault with the P5/P6 tweeters with age (10 years) - Normally B&W just provide a new cone / voicecoil assemly for blown tweeters (as the magnet structure is still fine) - however they sell complete new P5/P6 tweeters basically at cost to fix the problem.

                So - when you say repalced the tweeters in your P6 was it just the cone / voice-coil or the complete units?

                Geoff
                Last edited by Aussie Geoff; 26 December 2004, 08:15 Sunday.

                Comment

                • junior77blue
                  Senior Member
                  • Nov 2004
                  • 635

                  #9
                  I believe it was the complete unit, i have the 'old' one in my hand. How can I confirm this? If I get a chance later, I will post a photo.

                  Comment

                  • Aussie Geoff
                    Super Senior Member
                    • Oct 2003
                    • 1914

                    #10
                    Junior77,blue,

                    If it is heavy and has the magnet strucure it is complte. If it is light (1/2 ounce) and has just the voice coil and cone etc - it is not the complete unit..

                    Geoff

                    Comment

                    • junior77blue
                      Senior Member
                      • Nov 2004
                      • 635

                      #11
                      Based on your description, then NO they only replaced the voice coil, cone & plastic baffle. Very light indeed....

                      I really hate lugging these speakers around...ugh!

                      Thanks for the help...

                      Comment

                      • Aussie Geoff
                        Super Senior Member
                        • Oct 2003
                        • 1914

                        #12
                        Junior,

                        Sounds like we may have a solution then. Speak to your dealer and have the ferro fluid in the tweeter magnets checked - if it is thick like treacle (which I would bet on!) then you need complete new tweeters which should solve your problem and return the P6s to their former glory!

                        Geoff

                        Comment

                        • junior77blue
                          Senior Member
                          • Nov 2004
                          • 635

                          #13
                          Well, I contacted my dealer today to confirm what was replaced. They did only replace the 'cone and coil'. It would cost me $200 USD to have both tweeters replaced. The dealer stated after contacting B&W that this is a rare case. Is there a way to get a hold of B&W to get the full story behind this? Or can I have ur contact that had the original problem with the P5s so that I can see if it trully has the same symptoms?

                          Can you 'check' the condition of the ferro fluid, or does it leak out when doing so? Is this something I can do, or must a dealer do this?

                          Comment

                          • Aussie Geoff
                            Super Senior Member
                            • Oct 2003
                            • 1914

                            #14
                            Junior,

                            I have Emailed your details and this thread to my colleague who had the issue with his P5 tweeters so he can contact you...

                            Geoff

                            Comment

                            • muzick
                              Junior Member
                              • Nov 2004
                              • 8

                              #15
                              Hi!

                              I am the guy that AussieGeoff is referring too. The sound from my P5 tweeters deteriorated gradually and I became very less satisfied with the speakers, not realising that the treble was becoming so badly affected. I swapped the *whole* tweeter assembly - magnet and all - with the tweeters from my B&W CDM1 SE's that were in temporay storage. The tweeters just happened to be escactly the same! WOW! what a difference - the P5's now came to life!!

                              Now figuring I couldn't really do any harm to my defective tweeters, I thought that I would "examine" them. Removing the dome/voice coil assembly was quite easy with a little bit of care. It was then that I noticed the thick "mud" that should have been a light fluid. The ferro fluid had simply congealed and become stiff. Given that the assembly was easy to remove, I compared it with the good tweeters from my CDM1's. They of course were fine.

                              New tweeters ordered ... and email to B&W... Turns out to be a known problem. At that time the speakers were made, any excess hardner used in the glue during manufacturing had a tendency to react with and adversely affect the ferro fluid. Anyway, B&W were very appologetic, but the speakers were long-time out of warranty.

                              A good contact at a B&W dealer that I frequent where I live now managed to get me replacements at cost, but it wasn't cheap to get them fixed still.

                              The email will have been archived a long time ago - I'll see if I can dig it out though.

                              BTW - overly loud music can also do the same to the ferro fluid. I don't like to play speakers loudly, so that was not the cause in my case. Before replacing the tweeters, a friend of mine at work suggested i replace the capacitors with audiophile grade components of a similar value. It didn't make a difference that I noticed because of the fundamental problem that still existed, but had I compared the capacitor chance with working tweeters then I may have perceived a difference.

                              Anyway, that was a couple of years ago and I'm still using the speakers - until I get a chance to replace them with the new 800 series units - probably the 803D. I would be loathed to get rid of them though.

                              The magnet assembly by the way was about 1kg in weight. The voice-coil/dome was only a few grams. Only the whole assembly could be replaced.

                              One other thing, if I were in this situation again, I might try sourcing some ferro fluid myself and clean out the congealed stuff with some solvent. The units may beome more damaged, but what the hell - I would have nothing to loose since they would be write offs anyway.

                              Best regards, and good luck,

                              Paul

                              Comment

                              • muzick
                                Junior Member
                                • Nov 2004
                                • 8

                                #16
                                ...Just one other thing... You say that the sound didn't improve after having the tweeters changed - that sounds strange.

                                The transformation for me was huge. I took the liberty of checking the ferrofluid in the new tweeters - just to be sure that the replacements weren't also adversely affected. You might want to consider doing that check yourself.


                                Rgds, Paul

                                Comment

                                • junior77blue
                                  Senior Member
                                  • Nov 2004
                                  • 635

                                  #17
                                  Thanks for the post!

                                  Well, they only replaced the voice-coil/dome not the magnet assembly.

                                  Can you confirm the sound quality prior to being fixed being dull, or having a "cupped-hand-over-mouth' sound?

                                  Do you recall what date (year) these speakers were purchased? Mine were purchased jan of 1997.

                                  Comment

                                  • muzick
                                    Junior Member
                                    • Nov 2004
                                    • 8

                                    #18
                                    I'm about 95% certain that my P5's were purchased in 1997. Yes - the sound - prior to replacing the tweeters - lacked any sparkle. They were not only dull and lifeless, but what treble did eminate from the speaker was pretty coarse sounding - distorted for sure.

                                    Paul

                                    Comment

                                    • HDurieux
                                      Junior Member
                                      • Apr 2009
                                      • 1

                                      #19
                                      Cleaned P6 tweeters

                                      Hi I had exactly the same problem. As mine were dead I opened the P6 tweeters and discovered the same “mud” Muzick describes above.
                                      I removed the ferro fluid with some stiff paper “ took me 20 minutes” and reassembled the tweeters.
                                      Honestly they sound as good as before.
                                      Thanks for your detailed describtion Muzick.

                                      regards

                                      Comment

                                      • RappeFiets
                                        Junior Member
                                        • Aug 2016
                                        • 2

                                        #20
                                        Hi,

                                        I just bought a second hand B&W P6 which are not in too good shape. The casings are a bit damaged also one of the tweeters is badly damaged and even has a small crack in it. Thankfully the woofers are fine. Also the grilles are missing.
                                        A few weeks ago I sent an email to B&W asking for a new membrane and I was amazed to find out that they had still one left. Last weekend I fixed the broken tweeter and now its working like a charm, even better then the other one. The ferrofluid I already changed with new one so that should not be a problem. What I was wondering does anyone perhaps still have a broken tweeter part of the P6? membrane, grille or diaphragm? What I want to do is take my broken membrane and take out the diaphragm and put in a aftermarket.

                                        Cheers Cor

                                        Comment

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