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SBL Mid Life Upgrade

Discussion in 'd.i.y.' started by Jennifer F, Dec 20, 2005.

  1. Jennifer F

    Jennifer F pfm Member

    This is one for the speaker guru's out there... I have been debating the merits of upgrading my SBL's, however, nothing I have demmed has worked as well in the room other than the SL2. Given that I don't have SL2 cash loitering at the moment, and that there is nothing fundamentally wrong with the SBL, I wondered what people's thoughts would be on replacing the standard scanspeak tweeters wtih something a little more exotic from the range.

    I believe that the ring radiator would fit in the SBL chassis with minor physical work. How well do people think this would integrate with the naim driver? How much work would need to be done to the crossover?

    In summary would it be worth the effort? Please debate!!!

    David
     
  2. jonnoshore

    jonnoshore physicist, engineer and healer

    I remember one of the forums had a guy who had mega-modded a pair of SBL's... including mounting the tweeter housing to the rear wall!

    I always thought the spikes into the wood thing for the main bass unit was always a compromise of function over practicality. Especially as the smallest knock or bump could wiggle the spike in the wood then potentially ground out the silicon seal (you would never know) unless you resealed them...

    I now use IBL's as they are smaller (WAF) and fit with my smaller room better 13ftx13ft. They are active mind ;-)

    Would be interested in knowing views on the upgraded tweeter (same in IBLs) as I am active I assume this would be easier to match / adjust.
     
  3. Ozi2

    Ozi2 Veteran Member

    jonnoshore,
    SBLs tweeters do match with their woofers. If you change tweeters, you will need to change something in the crossower. What about SBL crossower upgrade from Avondale site?!
    Some says that they sound better when you slightly unscrew screws on crossower box, but I still didn't try with mine as I wait new furniture which will allowed me putting them close to the back wall.
    Anyway, I wouldn't care for an upgrade if SBLs are latest spec. Maybe couple of new CDs would do the job.
    That's just my opinion.

    Oz
     
  4. rubaiyat_23

    rubaiyat_23 pfm Member

    Annular tweeter not sparkly on top, and needs to be crossed higher (higher Fo), i.e., won't work without crossover modification.
     
  5. Jennifer F

    Jennifer F pfm Member

    For reference, I have a home made pre amp (balanced with remote controls etc) and have built several power amps. Speaker DIY is a grey area to me to say the least, I have a spare pair of SBL crossovers and as such am quite happy to sacrifice them to as a working model until building the proper hardwired units. I have never had a go a modifying speakers before or designing them, as such I am really seeking advice from the speaker guru's as to whether they believe that this could be a worthwhile exercise.

    I have been very impressed by several speakers using the top of the range scan speak tweeters, sadly they have all had ported bass mid drivers, which would not work in my relatively small 11*15 room. As such the idea of putting the superior tweeter in the naim chassis has significant merit. Obviously though a speaker is more than a collection of exotic drive units.

    David
     
  6. Markus S

    Markus S 41 - 29

    David, I would think the tweeters are fine, I don't think they ever were a weak point in the speaker. Putting in different tweeters may not be as easy as you think, they may need a different cut-out on the tweeter baffle.

    If you want to do something to your SBLs, how about swapping some crossover parts for better alternatives? IMHO the SBL drivers are better than the crossover (which is why going active is very worthwhile with them).
     
  7. Jennifer F

    Jennifer F pfm Member

    Markus,
    I would love to go Active. Sadly the cost of a 2nd pair of Klimax mono's makes that very very prohibitive. Then again I am considering building some new power amps that might get close to Klimax performance. The crossovers will definately get an extreme makeover in the near future.
    David
     
  8. Markus S

    Markus S 41 - 29

    Please tell us about the results.
     
  9. James

    James Lord of the Erg\o/s

    David,

    Tweeters are not the easiest driver to retrofit into an existing design without some change to the crossover. There is also suggestion that the Scan-speak 2008 tweeter used by Naim is slightly modified, and so you can't even compare the published response and impedance graph to get a close match with another tweeter. If you are hell-bent on getting a better tweeter (and there are plenty better, e.g. Hiquphon OW1, Seas Millennium, Scan-speak 2905s, Morel MDT33 etc), then you'll have little choice but redesign the XO, which will require measurement and computer modelling capabilities.

    James
     
  10. colasblue

    colasblue pfm Member

    there are three variants of SBL's about of which the MK1 is noticably inferior to the later two (though still very good).

    If you have the pre '95 versions then your best course might well be to upgrade to a later pair - even if you have already had the bass drivers upgraded. The improved cabinet is not something you can get by DIY.
     
  11. Jennifer F

    Jennifer F pfm Member

    James,
    I am quite happy to investigate and play, I have spent many hours playing around building amplifiers. Speakers are just an unknown area at present. If I had the space for a workshop then I would have already followed in your footsteps and built several pairs, especially given that I work 5 miles from Wilmslow audio.
    I suppose my interest was more down to whether anyone thinks it is worth the effort or not. I believe that the naim mod is to glue a small brass mass damper on the back on the unit. I have not taken one apart to investigate, but I am told that this is the case.

    Colasblue,
    I have heard many pairs of SBL's some of the best systems have been based around some of the oldest units. I am sure in academic terms there is a difference, however, I suspect that setup and room interaction are more significant. I would also say that the veneer choice makes a difference too as Rosewood is a thicker veneer, piano black is veneered then lacquered so again is thicker.

    I think that I was spoilt by having quads in the past, I am seeking that quality of treble from a non electrostatic speaker. I think with some of the units that James has mentioned htis may be possible, I am not so sure about the 3008 though. that said the SBL offers an all round balance that is hard to beat. They are the only speaker that have stayed in my system any length of time since the quads. (the quads went when I moved house as they would not fit in the new place).
    David
     
  12. James

    James Lord of the Erg\o/s

    David, it is worth it only if you have the equipment and means to do it properly. Unfortunately, doing it by ear is very much hit and miss. I think Naim also remove the ferrofluid from some of their tweeters, though I'm not sure if that applies to the SBL.

    You might like to contact AshleyD and ask him what he replaced his SBLs with.

    James
     
  13. colasblue

    colasblue pfm Member

    The difference between early and late cabs is significant

    this I know since I upgraded from a 1986 pair to a 1997 pair.

    The later ones are in many peoples' opinion better than SL2's, so if you want but can't afford SL2's and your using an early pair then I'd have thought getting a late pair would be a least a good choice and possibly even a no brainer.

    (PS I use a 4 pack so if I really thought I could do significantly better than SBL's in the same space I wouldn't hesitate - trouble is I probably can't).

    I doubt you can really get much improvement by changing the tweetrs though.

    I've always thought that the main SBL issue is a slightly vague mid range which is down to that big bass/mid driver being just too hard for most amps to control properly

    The only way I can really be satisfied with SBL's is to run actively which enables greater control.

    Before you start fiddling with your tweeters i'd have a play around with the SBL's with alternatively only Bass/mid and tweeters plugged in. You'll be surprised how little work the tweeters do and how high the XO frequency is.

    If I were buying a new pair of speakes to replace my SBL's (and I'm not) the SL2's wouldn't even get a look in. I'd be looking at one of the variants of Living Voice Avatars
     
  14. James

    James Lord of the Erg\o/s

    IMO, it's not so much amplifier control as driver mismatch. An 8-inch midwoofer starts to beam from about 500Hz and would have lost a significant amount of its off-axis amplitude by around 2kHz. In contrast, a 19mm tweeter needs to be crossed above 3kHz, and therein lies the basic design flaw of the SBL. Even Naim cannot bend the laws of physics.

    Going active keeps the separation of duties a bit cleaner, but doesn't really avoid the problem. However, by going to a larger tweeter (e.g. Seas Millennium or Scan-speak 2905 series) will enable the crossover to occur at 2kHz or even slightly lower, but an SBL it will no longer be.

    James
     
  15. Jennifer F

    Jennifer F pfm Member

    Colasblue,
    A friend of mine used to have a 4pack with late model SBL's mine are one of the first pairs made. His view was that mine with mk1 drivers sounded better than his 4 pack. Mine now have the mk2 bass driver in them which I agree is a significant improvement. I think I really am being fussy in that I miss my Quads so much, 2 years since they went but I have still not found anything that I like more. LV are just down the road from me, but I have not investigate their speakers as I understand them to need freestanding space. I must have something that lives against a wall.

    Really I need to apply patience, something that I am not good at, wait until I move house and then either build or buy a pair of speakers suitable for than environment. My liking for the SL2 at present I know is largely down to the fact that is likes to be flush to a wall. The speaker market has really changed over the last few years and there are a number of products that I would like to investigate.

    I agree about active, a friend has SBL's with two 250.2's and it is a lovely setup and a huge step from a single 250. I think that the Klimax mono's beat the smaller amps, however, there is something about the active sound that appeals. I used to have active kabers with 250's before the quads and they were great then.

    David
     

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