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Goodmans tweeters. Which DT?!

Discussion in 'd.i.y.' started by Musiciseverything, Jan 13, 2021.

  1. Musiciseverything

    Musiciseverything pfm Member

    Hi.

    I have acquired a lovely example of a pair of Goodmans magnum K2s. One of the tweeters is blown though.

    There is a nice chap on this forum offering to give me a set of Goodmans Dt4s.

    I can’t tell though whether mine are DT2s DT3s or DT4s.

    Does anyone here know these tweeters well enough to know what the differences are between them?

    I’ll try to send pictures. Maybe someone knows if the magnum k2 used a specific DT?
     
  2. a.palfreyman

    a.palfreyman pfm Member

    Is there a label or any markings on the body?
    I have some dt4s somewhere. Could dig them out and have a look.
     
    Musiciseverything likes this.
  3. ToTo Man

    ToTo Man the band not the dog

    There should be a blue label on the back of the magnet that tells you what DT version. If not then I'd say it's likely to be an early version. I don't have a huge sample size to refer to, but IME the ageing effect is very likely to cause just as much, if not more, variation in the performance of these tweeters than what DT model it is, so if you've been offered a matched pair of DT tweeters in good working order, I'd go ahead and buy them and not worry too much if they're a DT2, DT3 or DT4.
     
  4. Musiciseverything

    Musiciseverything pfm Member

    Hi. Yes there’s the blue label, on the back, but frustratingly no mention of a DT on there.

    No sense in sending photos really then. I don’t think there’s anything to visually tell them apart from any other DT.

    Scouring the internet just now for any info, I found a previous post of mine where you’d commented that you thought all DT iterations were basically the same with minor tweaks.
     
  5. Musiciseverything

    Musiciseverything pfm Member

    Strange that the quoted text of your reply in my reply shows that you said more. Sorry I hadn’t read that until I saw it in the quoted text.
    I’ll just take a pop on these then.

    Rereading your comments on that older thread of mine where you kindly uploaded some frequency curves, thanks for them, I see again that you mentioned that these tweeters don’t age too well. I was thinking to replace them with something different anyway. I have a new amp arriving in a few days that extends to 80khz, so I’d like tweeters that can make some use of that. These speakers to me have fairly good clean bass and nice rich, open and dynamic midrange, so a bit more air would make these a really fun speaker to my ears.

    I was looking at foundtek ribbon tweeters. Their lower range is 2khz which is the same as the crossover to tweeter on these Goodmans.

    Here’s the spec sheet. The photo is wrong. They have a round design case. http://manuals.audiomania.ru/data/fountek_neocd1-0.pdf

    I see they have a sensitivity of 90db which I think should match okay with the magnums, but i see the recommended cut is 3.5khz, so perhaps not ideal? I have another pair of speakers where the same driver that’s being used as the squeaker is being used as the tweeter, so I’m reckoning that it would work to raise the crossover point by way of a crossover tweak if necessary.

    Or perhaps you might know of a nice well extended tweeter that would be more suitable for just slotting in there?
     
  6. ToTo Man

    ToTo Man the band not the dog

    Yes, unless I've been really unlucky in my purchases, these DT units don't appear to age very well. I intended to open up a bad one to find out if it had ferrofluid inside it, but I couldn't prise the damn thing open! I'm afraid I don't know about the potential compatibility of modern tweeters.

    Another option would be to source a pair of Philips AD 0160 or Philips AD 0161 tweeters. Goodmans used these in Magnum K2 and Magnum SL models as well as their own DT units, I'm not sure which tweeters were used first or why they switched, but I can report that the Philips tweeters age much better, or at least the couple of pairs of units I measured do. As you can see in this graph, the response is nice and smooth and well-matched.
     
    Last edited: Jan 14, 2021
  7. Musiciseverything

    Musiciseverything pfm Member

    Getting a pair of these had been a consideration too. The graphs look good. I heard something about that troels guy saying they were the worst tweeters ever though!

    here’s the link http://www.troelsgravesen.dk/WWDT.htm

    is he actually saying that he ended up disproving his negative assumptions and that the tweeter actually measures and performs really well?
     
  8. ToTo Man

    ToTo Man the band not the dog

    Yes, I was aware of Troel's comments and I'm still not entirely sure what his message is! I've owned Goodmans Minister/SL, Havant/SL, Mezzo/SL, Magnum K2/SL and Magister, at various times, some with the DT unit and some with the Philips unit, and I generally preferred the Philips unit. Don't get me wrong, I'm not saying it's a superb tweeter, but it's good enough IMO to be used in these Goodmans models and is not inferior to the DT model, especially when you take the unpredictable effects of ageing into consideration. Again, this is only my opinion. If you're able to get a pair of DTs at a good price in good working order then I'd recommend starting there. If you don't like the DTs, then you can try the Philips. If you don't like the Philips either, then it's back to the drawing board!
     
  9. Musiciseverything

    Musiciseverything pfm Member

    Thanks. I’m getting the impression that the Phillips are fairly decent, and extend a bit more than the DTs. Is that why y of preferred them?
    The nice chap Nero on the other thread isn’t wanting any money for them so I’ll go with that path of least resistance first. Makes sense too to do a like for like swap and see how they get on with my new amp. I can imagine I’ll enjoy them as such for a while before I get the itch to maybe try something else. incidentally he lives in Chichester, and I see there’s a town near there called Havant. What’s the Goodmans connection do you know?

    Also, I just saw you’re in Glasgow too. I always assume I’m speaking to someone down south when I’m on here because chances are I would be.
     
  10. ToTo Man

    ToTo Man the band not the dog

    The Goodmans factory was in Havant, I believe, but I'm sure @Beobloke will put me right if I'm mistaken.

    Regarding the DT, I owned and sold most of my Goodmans speakers before I had the equipment to measure frequency response. I haven't measured the Philips unit when it's actually installed in a Goodmans speaker, nor have I measured a DT in this context, so basing evaluations on raw responses in isolation isn't telling the whole story. Based on my fading memory, I preferred the Philips tweeter because it sounded more alive and 'sparkly', and at that time I had a preference for speakers with a detailed and airy top octave.

    The only Goodmans speaker I still own is the Achromat Beta, I had three pairs of these at one time but now only one. The Achromat series use a DT-style tweeter (it doesn't have a blue label on it but it looks just like a DT). You probably saw in my other thread that four of these six DT-style tweeters exhibited some very unusual behaviour between 10kHz-13kHz that made the speakers sound hyper-detailed. I assume this was caused by 35+ years of ageing and hope it was not how it left the factory. Thinking back I wonder if this was responsible for accelerating my high-frequency hearing loss, as I owned these speakers for years before discovering that the "hyper-detailed sound" was in fact due to a +10dB spike at 13kHz! :eek:
     
    Last edited: Jan 14, 2021
    Musiciseverything likes this.
  11. mega lord

    mega lord Centre tapped

    What Fecked my high frequency hearing was 30 years of drumming, especially riding the crash cymbal .
     
    ToTo Man and Musiciseverything like this.
  12. Musiciseverything

    Musiciseverything pfm Member

    Haha, playing them loud eh? I'm not massively into listening at really loud volumes. I used to be in my youth, but years of performing through big sounds systems and being around live gigs has pretty much filled my boots for that. Well, thinking about it, I like it quite loud in the car!

    I heard the Goodman's factory was in Wembley. Maybe they had another facility making certain parts in Havant then.

    I should obviously ask this Nero gent who lives near there.
     
  13. Musiciseverything

    Musiciseverything pfm Member

    Oaft, that'll do it!

    I too have thoroughly abused my ears, through playing guitar in a metal band as a teen, dancing by the bass bins at house and techno nights through the nineties, generally being a professional musician and being around high SPLs, for most my adulthood. Oh and I've been a Piper since I was 7!!! And all the time belligerently refusing to wear ear plugs.

    I had a professional ear clean recently - which I'd highly recommend by the way, it was amazing what they pulled out from the depths! - and a before and after hearing test. The after results were astonishingly good, showing me to have better than average hearing for my age and not far off perfect! But how though?!!!!
     
  14. Musiciseverything

    Musiciseverything pfm Member

    hyper detailed sound doesn’t sound like too bad a thing whatever the cause! I think flat response curves are over rated. Well, it’s ideally what you want in a good studio monitor, but things can sound really fun when they’re not flat.

    btw, Nero confirmed that there was indeed a Goodmans factory in Havant, and he worked there as his first job after uni, which is why he has a few Goodmans bits lying around. I wonder if that will mean these tweeters havnt been used. Would that mean that maybe they’ll not have aged and shifted as much? Or is it factors other than use that age them?
     
    ToTo Man likes this.
  15. ToTo Man

    ToTo Man the band not the dog

    Your guess is as good as mine! Theoretically unused should be a safer bet as the drivers won't have been subject to being (over)driven, but if it's been stored in a cold/damp environment or is design that used ferrofluid then it may well have still deteriorated. You'll soon find out!...
     
  16. retrospective

    retrospective pfm Member

    I think i may have a pair of dt3's there's a thread from a few years ago 'Mid 70's speaker identification' with some images

    Give me a nudge if they're the ones

    Mid 70's speaker identification
     
  17. Musiciseverything

    Musiciseverything pfm Member

    Oh thanks. I've been posted an unused pair of dt4s by a gent called John who used to work at the Goodman's factory in Havant
     
  18. Beobloke

    Beobloke pfm Member

    No, you’re quite right!

    After they re-located from London, during their heyday the factory was in Downley Road which is in the north of Havant.

    They then moved to a purpose-built new factory in the 1980s - this is in Ridgeway, just off Marples Way and is right beside the A27. The trees are tall now but you can still just about see it from the A27 - it’s now occupied by FatFace.
     
    ToTo Man likes this.
  19. Musiciseverything

    Musiciseverything pfm Member

    sorry for the kurt reply yesterday, I was constantly in company, didn’t get a minute to myself.
    I’ve seen that post before when I was scouring the internet to find out anything about the random hmv speakers I had acquired. They were a different model to those ones, I t honk earlier, and sound actually really surprisingly good. How did you find that your ones sounded? Did you replace those Goodmans tweeters for something else I take it?
     
  20. retrospective

    retrospective pfm Member

    Still to this day i haven't used them for more than a few minutes to test they worked!
    When i was researching them i happened upon a pair of Mezzo 3 that i liked the look of so they were retired to the garage where they still reside.
     

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