crossover inductors

[Dave Hewitt]

Hi,
This may be usefull to Marco as i know he mentioned upgrading the inductors in his tannoys to copper tape type.I bought some superb looking inductors ,air cored very large copper tape type,same inductance as the bass ones in my H2 speakers,but with slightly less resistance.I thought two birds with one stone here get rid of the ferrite core ones and a slight increase in bass sensitivity.Well fitted these and the bass has departed to I know not where.I thought give them a fair chance,but after several days it was still no good,just refitted the original ones and the sound is back to normal
Regards Dave.

[DSJR]

DIY on *decent* speaker crossovers is fraught with danger I think. Better speakers were "voiced" with what they used and although moving components around can bring about improvements, just swapping caps and coils for so called better ones can totally upset the way the crossover works and do all maner of things to the frequency response.

How much are software speaker calibration devices these days? i think the popular one was mlssa

http://www.nutshellhifi.com/MLS/index.html

OK, you have to get some knowledge before using such things, but it would sure help in understanding what you're doing to the speakers concerned. Hopefully Marco's Tannoy crossovers would have been put together and designed with similar understanding as I know Tannoy did much to re-design them in the early eighties.

http://www.nutshellhifi.com/library/speaker-design1.html

[Marco]

Hi Dave,


This may be usefull to Marco as i know he mentioned upgrading the inductors in his tannoys to copper tape type.I bought some superb looking inductors ,air cored very large copper tape type,same inductance as the bass ones in my H2 speakers,but with slightly less resistance.I thought two birds with one stone here get rid of the ferrite core ones and a slight increase in bass sensitivity.Well fitted these and the bass has departed to I know not where.I thought give them a fair chance,but after several days it was still no good,just refitted the original ones and the sound is back to normal


That's interesting, and thanks for the info. I'm sorry that fitting the new inductors in your speakers didn't work out. However, in my case with the Monitor Golds, I think it'll be different, as there are none of the original Tannoy crossovers left.

Dave and you fitted new caps and resistors the last time, upgrading the ones in the crossovers Chris (from Big Ears Audio) had supplied with the drive units, which left the inductors he used, currently in place now.

Therefore, when it comes to upgrading them (as those weren't supplied by Tannoy) with something better of the same value, I should obtain a noticeable improvement.

I was thinking of trying these Goertz Foil ones, as recommended by Andre:

http://www.goertzaudio.com/contents/en-us/d19_Foil_Inductors.html

I'll give you a shout when I've got the bits, and you guys can have some lunch and a sesh at mine. I've got a few other projects to finish first, though.... :)

Marco.

[Rare Bird]

I've never had a lack of Bass just more clean, i suppose some would class it as a lack of.

The best inductors i ever used were RATA Iron cores..Over sized cores, very short windings.

[Dave Hewitt]

Hi Marco,Thats what i'm getting at perhaps the tannoy laminated inductors would be better for you as the crossovers were not tried with these in place. Read somewhere else that the original stepped tannoy inductors are very good
Dave.

[Rare Bird]

yes id be carefull with the tannoys, they sound lifeless as it is :lolsign:

:sofa:

[Marco]

Hi Marco,Thats what i'm getting at perhaps the tannoy laminated inductors would be better for you as the crossovers were not tried with these in place. Read somewhere else that the original stepped tannoy inductors are very good...


That's true, Dave. It might be worth getting hold of some again to try :)

Although, don't you think that with the advancement of technology, high quality inductors now (like the Goertz or Duelund types) would likely be superior?

I know it didn't work out with your H2s, but then they're not over 50 years old....!

Marco.

[DSJR]

Not in my experience Andre. In fact, the older ones are too lively if anything and need careful crossover implementation to sort them out, something the modern prestige crossovers seem to do perfectly IMO, judging by the smaller ones I've heard in recent times.

I'd love to hear some humungous Tannoys again, it's been so long.

[Marco]

yes id be carefull with the tannoys, they sound lifeless as it is :lolsign:

:sofa:

Lol - they don't sound "lifeless" at home, dude - far from it!

Marco.

[Rare Bird]

You have to use them like giant headphones i know :lolsign:

End of the day it's all trial & error with crossover mods..

[DSJR]

You can talk Andre, with those 'orrid Mission "squeakers" - ghastly things, all of them.....:ner:

[Reid Malenfant]

I bought some superb looking inductors ,air cored very large copper tape type,same inductance as the bass ones in my H2 speakers,but with slightly less resistance.I thought two birds with one stone here get rid of the ferrite core ones and a slight increase in bass sensitivity.Well fitted these and the bass has departed to I know not where.

Ah, there is the problem in a nutshell ;) You fitted new inductors with LESS resistance than the originals :rolleyes: Not many people go so far into loudspeaker design that they realise this, but the series resistance of the inductor/s feeding the bass driver affect the systems Q at the driver resonance.

People that have possibly switched from solid state amplifiers to valve will likely understand this as the same sort of effect comes about. The highish output resistance of a valve amp can give a fuller bass response. You can get the same effect by putting a small series resistance inline with a solid state amp.

What you have done by fitting an inductor with lower series resistane is lower the system Q & reduced the bass response from the speaker. The only thing you could do if you still want to use the new inductors is add a series resistance in line with the inductor to bring it back to the same value as the originals.

The original inductor was factored in at the design process to give the desired bass response with that bass driver in that cabinet size ;)

[Rare Bird]

You can talk Andre, with those 'orrid Mission "squeakers" - ghastly things, all of them.....:ner;


Dream on :lolsign:

[Dave Hewitt]

Hi Mark
Thanks for your advise, it makes sense.
Cheers Dave.