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Professional Speaker testing ?

Discussion in 'audio' started by AudioAl, Dec 15, 2014.

  1. AudioAl

    AudioAl pfm Member

    Professional Speaker testing ?


    I have a pair of Harbeth HL1 MK4 speakers

    Harbeth are not interested due to age and say they no longer have any parts for these

    Can they be tested other that If they sound OK they are OK

    Also how would you test the cross over units ?

    I want to make sure they are as good as I can get them / restore them for use in my system

    Any advice welcome ( other than buy a new pair :p )

  2. Julf

    Julf Evil brother of Mark V Shaney

    A good place to start is playing a frequency sweep at reasonable sound level. If you don't hear any obvious distortion, and the level stays reasonably constant over the frequency range, they are probably OK. Listen specifically for the transitions between the elements.

    If the speaker elements are physically OK, the only things that get bad with age are the capacitors in the crossovers.
  3. davidsrsb

    davidsrsb pfm Member

    I have come across cabinet glue coming apart
  4. Julf

    Julf Evil brother of Mark V Shaney

    Ah, yes, good point. I was thinking of "invisible" things.
  5. AudioAl

    AudioAl pfm Member

    OK , How do I do a frequency sweep with a TT or R2R or CD player ?
  6. mattgbell

    mattgbell canis pictus

    Download a frequency sweep from the web and burn it to a CD. Simples.
  7. Martyn Miles

    Martyn Miles Trade: MGM Audio

    I have a pair of originals, the HL Monitor, so older than yours.
    The crossovers should be fine. They were well constructed, using high quality components.

    If the bass/mid. drivers aren't fouling then they are very likely to be OK.
    The tweeters can lose output, as one of mine did. Fortunately Falcon Acoustics can supply genuine new Audax ones.

    I assume your foam grilles have deteriorated. I had new cloth ones made by Sid Chaplin of Traditional Radio Grilles. Superb, they are.
    If you have any other questions send me PM.
    Glad to help.

    M Miles.
  8. Julf

    Julf Evil brother of Mark V Shaney

    Or there used to be system setup / test CD's for sale - but yes, much easier to download (or make, with audacity or other similar program) a file and burn it.
  9. steve_1979

    steve_1979 pfm Member

  10. Arkless Electronics

    Arkless Electronics Trade: Arkless

    If you have no reason to suspect any fault then they are probably OK.
    Testing them is a minefield and will probably give erroneous results.
  11. Cjm75

    Cjm75 pfm Member

    Just watch your levels with test tones, they can be rather loud!

    I nearly soiled myself the first time i played some
  12. formbypc

    formbypc pfm Member

    If you test them and find out you need parts, what then? Harbeth say you can't get them. Where does that leave you?
  13. Tony L

    Tony L Administrator

    Assuming they sound OK they probably are ok. Most fault conditions are obvious e.g. bass drivers rubbing, tonal imbalances left to right etc. If they seem fine then the only things I'd do personally would be to replace any electrolytic caps in the crossover with fresh ones as they have a very finite lifespan (every vintage speaker I've done has sounded better afterwards) and also to rotate the bass units 180 degrees in the cab so what was up is now down - it will help correct any cone/spider sag caused by 20+ years of gravity.
  14. davidsrsb

    davidsrsb pfm Member

    My 752 joints were invisible until the DSOTM bass made the cabinet start snapping open and closed.

    Be careful with frequency sweeps, they can easily fry tweeters
  15. RustyB

    RustyB Registered Ginga

    Tweeters: can be sourced, as above.

    Woofers: can be re-aligned if necessary.

    Crossovers: easy enough to replace/substitute components.
  16. Martyn Miles

    Martyn Miles Trade: MGM Audio

    In addition to the previous, succinct post:

    OK, let's look at this logically. If the bass/mid. cones need replacing (unlikely) then there are organisations that can do that. The Wembley Loudspeaker Co. do repairs, but there are others with more expertise with poly. drive units.
    As I said, the tweeters are available.
    Crossovers components can be replaced. The inductors are unlikely to be damaged. Cabinets ? Perhaps more difficult, but there are restorers.
    Grilles? Yes, as I said, they can be made.
    If depends how much you value classic speakers, but a pair of HL Mk. IV recently sold for nearly £500.
    They are more valuable than my early ones.
    Hope that helps.
    M Miles.
  17. Julf

    Julf Evil brother of Mark V Shaney

    Wow, I've only seen that happen with really amateurish DIY projects!

    Maybe the cabinet snapping open and closed is what provides PRaT? ;)
  18. Arkless Electronics

    Arkless Electronics Trade: Arkless

    I've see the bottom panel of speakers ripped off when trying to remove them from stands by the adhesion when blu tack etc has been used!
  19. YNWOAN

    YNWOAN 100% Analogue

    They must have been astonishingly badly made then!

    I've seen quite heavy speaker stands lifted with speakers attached by Blutack but never seen a cabinet come to pieces.
  20. Arkless Electronics

    Arkless Electronics Trade: Arkless

    I've seem it once myself but have heard of it happening on several other occasions so maybe not as rare as one may think....

    I've known it take the strength of two large blokes to get the speaker free of the blu tak grip several times.

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