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Thread: WTD: Pair of Celestion HF2000 tweeters (must meet strict criteria)

  1. #1
    Join Date: Feb 2015

    Location: Glasgow

    Posts: 109
    I'm Richard.

    Default WTD: Pair of Celestion HF2000 tweeters (must meet strict criteria)

    I'm looking for a pair of Celestion HF2000 tweeters that I can store away as backups for my Ditton 66.

    However they must meet very strict criteria, because over the last decade or so I have procured some five pairs or so from eBay, and of these 10 units I have only been able to match up 2 that are within ± 1.5dB across their 6kHz-20kHz operating range. Some are out by as much as 5dB or even 10dB in a couple of cases!).

    So, if you have a pair of HF2000's and can prove with measurements that they are matched to ±1.5dB from 6kHz-20kHz, please get in touch as I'd be willing to offer a generous sum for them.

    Cheers
    Last edited by ToTo Man; 20-09-2018 at 17:36.
    Main System: Mac Mini > Schiit Yggdrasil 2 OG > Yamaha A-S3000 > Celestion Ditton 66
    Headphone System: Mac Mini > Schiit Yggdrasil 2 OG > Sparkos Aries / Schiit Mjolnir 2 > Sennheiser HD600

  2. #2
    Join Date: Oct 2017

    Location: Rugeley

    Posts: 300
    I'm Steve.

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    At frequencies above 6k, and certainly over 10k, I would doubt my ability to detect a difference of a 2, 3, 4 or even 5 dB on a stereo recording. In the mid range, yes for sure and also at lower frequencies. But I fully understand what you're trying to achieve. It's a big ask that someone is in possession of that level of data, but best of luck.

  3. #3
    Join Date: Feb 2015

    Location: Glasgow

    Posts: 109
    I'm Richard.

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    Quote Originally Posted by vintagesteve View Post
    At frequencies above 6k, and certainly over 10k, I would doubt my ability to detect a difference of a 2, 3, 4 or even 5 dB on a stereo recording. In the mid range, yes for sure and also at lower frequencies. But I fully understand what you're trying to achieve. It's a big ask that someone is in possession of that level of data, but best of luck.
    I know, but I can only live in hope! I'm unfortunately cursed with the ability to hear very small differences between left and right channels, even at high frequencies, which does not fit very well with my love of vintage hifi. Luckily I already have a pair of HF2000's that are pretty well matched, so I don't mind playing the long game. I expect I'll still be 'bumping' this thread a year from now!
    Main System: Mac Mini > Schiit Yggdrasil 2 OG > Yamaha A-S3000 > Celestion Ditton 66
    Headphone System: Mac Mini > Schiit Yggdrasil 2 OG > Sparkos Aries / Schiit Mjolnir 2 > Sennheiser HD600

  4. #4
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,869
    I'm Lawrence.

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    Very long shot this. You might miss out on a tweeter that while it might not match it's own pair it could match one of yours. If people don't have the equipment you could maybe pay postage both ways to check them yourself?

    Sent from my BLN-L21 using Tapatalk

  5. #5
    Join Date: Oct 2017

    Location: Coventry

    Posts: 130
    I'm Mick.

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    Quote Originally Posted by ToTo Man View Post
    I'm looking for a pair of Celestion HF2000 tweeters that I can store away as backups for my Ditton 66.

    However they must meet very strict criteria, because over the last decade or so I have procured some five pairs or so from eBay, and of these 10 units I have only been able to match up 2 that are within ± 1.5dB across their 6kHz-20kHz operating range (some are out by as much as 5dBs!).

    So, if you have a pair of HF2000's and can prove with measurements that they are matched to ±1.5dB from 6kHz-20kHz, please get in touch as I'd be willing to offer a generous sum for them.

    Cheers
    Hi Richard, how are you testing the response?

  6. #6
    Join Date: Feb 2015

    Location: Glasgow

    Posts: 109
    I'm Richard.

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    Quote Originally Posted by Mixc View Post
    Hi Richard, how are you testing the response?
    Mick, I'm measuring with a UMIK-1 USB mic and REW software using the automatic sine wave sweep with manually selected cut-off points of 2.5kHz and 22kHz. In hindsight I should have used 4kHz as the lower cut-off as there won't be much output below this once connected to the crossover. I imagine Pink Noise would work equivalently well. I kept the levels fairly low (<70dB @ 1m) to prevent risk of damage.

    I measured each HF2000 with no crossover, just connected straight to my amp (if you do this you need make sure your amp has no DC offset and you are feeding the tweeter with filtered content because you could damage it with frequencies below its normal operating range).

    I placed each tweeter face up on the carpet in the middle of my room, with the mic positioned 1 meter above it on a boom stand. I'm sure those with more knowledge/experience will tell me this isn't the best way to measure, but it's the technique I started off with so I best stick to it or else I'll need to repeat dozens of measurements again!

    However you measure, it's vital that the mic isn't moved until all measurements are completed, otherwise all bets are off!

    If you're interested you can see my results here:
    https://theartofsound.net/forum/show...ovation-thread
    Main System: Mac Mini > Schiit Yggdrasil 2 OG > Yamaha A-S3000 > Celestion Ditton 66
    Headphone System: Mac Mini > Schiit Yggdrasil 2 OG > Sparkos Aries / Schiit Mjolnir 2 > Sennheiser HD600

  7. #7
    Join Date: Oct 2017

    Location: Coventry

    Posts: 130
    I'm Mick.

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    Ive just read your post very interesting, So much effort....
    To me your measurement procedure should be plenty good enough. Its got my brain ticking, when i run a frequency sweep i can hear the focus of the sound change position (left to right) i put this down to room acoustics or my hearing, maybe my tweeters are not as balanced as they should be.Hmm.
    That never ending quest for perfection... Good Luck

  8. #8
    Join Date: Feb 2015

    Location: Glasgow

    Posts: 109
    I'm Richard.

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    Quote Originally Posted by Mixc View Post
    Ive just read your post very interesting, So much effort....
    To me your measurement procedure should be plenty good enough. Its got my brain ticking, when i run a frequency sweep i can hear the focus of the sound change position (left to right) i put this down to room acoustics or my hearing, maybe my tweeters are not as balanced as they should be.Hmm.
    That never ending quest for perfection... Good Luck
    Could well be room acoustics. When I measure a complete loudspeaker I measure each one in the exact same location as this takes the room out of the equation. Jump down this rabbit hole at your own peril, as once you have conclusive proof of an imbalance, your subconsciously far more likely to notice it and have the gnawing urge to remedy it!
    Main System: Mac Mini > Schiit Yggdrasil 2 OG > Yamaha A-S3000 > Celestion Ditton 66
    Headphone System: Mac Mini > Schiit Yggdrasil 2 OG > Sparkos Aries / Schiit Mjolnir 2 > Sennheiser HD600

  9. #9
    Join Date: Oct 2017

    Location: Rugeley

    Posts: 300
    I'm Steve.

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    Just a thought, and I'm not trying to throw a spanner in the works, if you're placing the tweeters down on carpet (i've not seen the carpet, thickness etc) then there's a possibility that subsequent tweeters placed for testing may be tilted slightly in comparison, a carpet not being a stable, repeatable support. This off axis effect would adversely affect the level of signals received by the mic, giving rise to a false comparison. You may have taken this into account of course with how the tweeter is 'placed' on the carpet.

  10. #10
    Join Date: Jun 2015

    Location: London/Durham

    Posts: 6,869
    I'm Lawrence.

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    Very good point if you're rounding to 0.5db could make all the difference.

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