Speaker help required...

Dedicated to those large boxes at one end of the room
Post Reply
Lee S
Old Hand
Posts: 664
Joined: Fri Aug 10, 2007 9:39 am
Location: UK

#1 Speaker help required...

Post by Lee S »

What are the more critical parameters when looking to find a replacement driver for a pair of speakers? The voice coil has gone in one of my loudspeaker's woofers and they are TDL units but unobtainium. I have all of the physical and TS parameters of the original, but trying to find one that has ALL of the right parameters is impossible. Are there any parameters that are more important than others or do they all need to be right to work in the existing cabinet with the existing crossover? I guess I can change some crossover components if need be to make it work. I'm just a bit clueless when it comes to knowing how to find a decent replacement driver that will sound as good as the originals?
©2020 Lee
chris661
Shed dweller
Posts: 2556
Joined: Mon Feb 22, 2010 7:29 am
Location: Sheffield

#2 Re: Speaker help required...

Post by chris661 »

It's difficult. Even if you can find something that matches the original specs, you can pretty much guarantee that the surviving driver won't have the same specs after however many years of "break-in".

What is the driver you're hoping to replace?

It's not just T/S parameters that need matching up - the crossover will be tuned for the upper range of the woofer, so you'll need to make sure the frequency response charts are similar, too, if you want a matched pair.

My recommendation would be to aim to replace both woofers.

Chris
steve s
Shed dweller
Posts: 2829
Joined: Wed May 30, 2007 6:19 pm
Location: east yorks

#3 Re: Speaker help required...

Post by steve s »

I would check that the speaker can be repaired... my lads b&w cdm1s bass driver stopped and it was the connection from the cone wire to the flexible wire on the cone that I resoldered . A prod around with a sharp metal screwdriver whist the speaker is powered up may reveal where the fault is... worst case is that the coil itself is burned out. . Usually through being thrashed... there's a guy in Keighley who repairs speakers and may well be able to repair it
Sorry i don't know his name but he works from his home and does all kinds of speakers ...
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
Lee S
Old Hand
Posts: 664
Joined: Fri Aug 10, 2007 9:39 am
Location: UK

#4 Re: Speaker help required...

Post by Lee S »

I was definitely going to replace them as a pair and not leave one original in. I think what I will do is sit on them and wait and see if any drive units come up on eBay for them. The speakers are too good to throw away or "ruin" by putting incorrect parts in.

Repair is another option Steve. I may look into that too. I tried calling Lockwood Electronics who allegedly bought up all of TDL and IMF stock ages ago, but they got back to me saying stock was long gone for those drive units. :cry:

The unit itself is a TDL unit, which was purportedly made for TDL by Elac and it is a "TDL 6DC 365" if anyone ever sees one or comes across any. Highly unlikely but you never know.

Thanks anyway.
©2020 Lee
Wieslaw Lipowski
User
Posts: 24
Joined: Wed Dec 24, 2008 9:53 pm

#5 Re: Speaker help required...

Post by Wieslaw Lipowski »

User avatar
pre65
Amstrad Tower of Power
Posts: 21373
Joined: Wed Aug 22, 2007 11:13 pm
Location: North Essex/Suffolk border.

#6 Re: Speaker help required...

Post by pre65 »

The only thing necessary for the triumph of evil is for good men to do nothing.

Edmund Burke

G-Popz THE easy listening connoisseur. (Philip)
User avatar
DSJR
User
Posts: 193
Joined: Mon Jan 11, 2010 11:11 am
Location: Suffolk Coastal

#7 Re: Speaker help required...

Post by DSJR »

Which TDL?

I know the driver designer for the TDL models and if I can get gold of him, he may be able to help as he has *some* bits and bods around. Depends what's needed. Of the old stock, I think Lockwoods may be able to help otherwise...
Chopsaw
User
Posts: 59
Joined: Sat Mar 21, 2009 12:47 pm

#8 Re: Speaker help required...

Post by Chopsaw »

Some useful info there. I have a pair of Studio 4s and one of the tweeters has a damaged dome. It's only a small crease and it still sounds fine but I would fix it if I had the opportunity.
Lee S
Old Hand
Posts: 664
Joined: Fri Aug 10, 2007 9:39 am
Location: UK

#9 Re: Speaker help required...

Post by Lee S »

Thanks DSJR. The model is the 'TDL Studio 1' but the pre-metal cone version. So NOT the '1M' but the '1'. The driver is labelled 'TDL 6DC 365'.

That Monacor doesn't seem a match at all. I have looked at the T/S parameters and the Q values are nowhere near, so they are not "as close to the specification & sound", unless the T/S parameters mean little to nothing? Also the physical size is completely wrong. That speaker is 165mm diameter and the ones in mine are 185mm diameter. The closest I could see are the SPH-176 and even those are only 175mm diameter. Maybe there was a smaller version of the TDL Studio 1. Or maybe the guy is thinking of the TDL Studio 0.5. Dunno, but AFAICS those Monacors are not a drop in.

See here under "6DC 365" https://www.falconacoustics.co.uk/down ... imftdl.pdf

The only ones I could find that are a close match are some ScanSpeak units, but even those are not perfect WRT to the T/S parameters and they are something like £160 each (!!) so I'm not willing to just take a punt and see what "they sound like" at that price... I could almost buy another complete pair of speakers for that. A mint pair went for £425 on eBay a couple of days ago, so £340 for a pair of woofers seems daft to me....

As I also said, I contacted Lockwood and they are LONG out of stock of ANY bits for that speaker..... no luck there.

Thanks anyway chaps !! :D
©2020 Lee
User avatar
Scottmoose
Needs to get out more
Posts: 1802
Joined: Sat Sep 08, 2007 11:03 am
Contact:

#10 Re: Speaker help required...

Post by Scottmoose »

Unfortunately, driver design in particularly the past 15 years has moved away from the type of units used in the TDL, so you'll struggle to find current equivalents. About the closest general production unit I can think of to that model (note I am not saying it is spectacularly close, though it's in the general ballpark) in terms of T/S spec. and materials is the snappily named SB17MFC35-8 from SB Acoustics. I wouldn't like to say about frequency response, but I doubt it would be close enough to work with the same low-pass you'll have in that Studio 1. If you want closer, you'll either have to have your existing unit rebuilt (best option if possible), or a custom unit made; even then you'll almost certainly have to do some DIY as it's unlikely even a custom driver will have a basket that exactly matches. Audio Technology could probably do it, notwisthstanding basket size, but you'll pay. Oh, you'll pay all right, never you fret about that. ;) Audio Technology make the best polymer cone (mineral filled polyprop to be precise) drivers on the market, but you get what you pay for and it comes at a big price.

Not the answer you're looking for, sorry. Thing is, priorities have largely changed in terms of the drivers since the TDLs were made. They were plastic cone units with a Q at the low end of moderate and a low Fs. Closer to small woofers in that sense; they were optimised for use in sealed and moderately well-damped vented or QW alignments like the TDLs. The plastic cones weren't usually the last word in resolution but had a lot of self damping so response should be fairly smooth and filtering easy. Since then, there's been a shift by most of the main manufacturers away from the heavily damped cones in an attempt to get more resolution; the price has typically been a more limited usable response range (upper and lower) and more work in the filter. Whether that's been worth it or not depends where your priorities lie.
'"That'll do," comes the cry of the perfectionist down the ages.' (James May The Reassembler)
Website www.wodendesign.com
Community sites www.frugal-horn.com & www.frugal-phile.com
User avatar
ed
retired
Posts: 5384
Joined: Thu Jun 21, 2007 4:01 pm
Location: yorkshire
Contact:

#11 Re: Speaker help required...

Post by ed »

Unfortunately, driver design in particularly the past 15 years
Unfortunately, driver design, particularly in the last 15 years

snigger

glad to see you're still on the case Scott.
There's nowhere you can be that isn't where you're meant to be
User avatar
DSJR
User
Posts: 193
Joined: Mon Jan 11, 2010 11:11 am
Location: Suffolk Coastal

#12 Re: Speaker help required...

Post by DSJR »

Have a word with Lockwoods, as they may have some spares (unlikely but ask).

I believe Elac may have made the original Studio 1 drivers (I do know the difference and sold many 1M's back then, even trying to own a pair a couple of years back - the metal cones these days are more audible than I remember sadly and my tired old Spendors sounded rather better in the mids). I know the TDL driver designer and he's trying to re-introduce the 'racetrack' bass unit which could be so good back then. He's not very 'accessible' these days though as his work for 'Tymphany' takes him all over the place, but I'll email and ask..
User avatar
Mike H
Amstrad Tower of Power
Posts: 20157
Joined: Sat Oct 04, 2008 5:38 pm
Location: The Fens
Contact:

#13 Re: Speaker help required...

Post by Mike H »

Lee S wrote: Wed Jan 23, 2019 5:14 pm Repair is another option Steve. I may look into that too. I tried calling Lockwood Electronics who allegedly bought up all of TDL and IMF stock ages ago, but they got back to me saying stock was long gone for those drive units. :cry:
Lee S wrote: Mon Jan 28, 2019 12:56 pm As I also said, I contacted Lockwood and they are LONG out of stock of ANY bits for that speaker..... no luck there.
 
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
David Pinnegar
User
Posts: 9
Joined: Wed Apr 10, 2019 1:40 am

#14 Re: Speaker help required...

Post by David Pinnegar »

The real thing that needs to match at least is the efficiency . . . and the impedance of course.

But voice coils can be fun - here's a nasty little repair I did for someone recently:
Image
Image

This is an aluminium voice coil with damage in the second turn, two turns removed and replaced by two turns of copper which I had with the join from aluminium to copper taken up onto the cone, and the copper having to detour up towards the cone so as not to foul the narrow 1mm voice coil gap. The brown is shellac which both insulates, prevents any oxidisation of any exposed aluminium and holds it in place.

Best wishes

David P
Attachments
DSCF1743.JPG
DSCF1744.JPG
Post Reply