92dB sensitivity tweeters

[Batty]

Whilst replacing the Vifa tweeters in the Howards I noticed that they are 89dB 1w 1m and the speakers quote 92dB 1w 1m, Tal came around yesterday with his measuring gear and yes the top end started rolling off at about 2.2KHz about 3dB and more down on the lower frequencies.

 

He has always maintained that the tweeters were not sounding too good on my speakers, so what tweeters can I replace them with to give me a higher gain top end?

 

Budget is dependant on time, the longer I wait the higher the budget, tax time next year could see me with plenty for a pair of good tweeters, or I could cash in up to $1k of shares.

Edited August 3, 2013 by Batty

[henry218]

sb29rdc is about 92db (4ohm) and scan hds (8ohm) is 91db.

im assuming this is d27, most of that models are 6ohm.

but change of impedance (as its different driver) will change the xo points and response. and could possibly change the impedance plot for the speakers.

[Batty]

Sorry the Vifa is a D25 which is 6 Ohm

[henry218]

yeah, so the if used the 4ohm means the xo point will moved to lower freq.

browse parts express and madisound, although it seems not that too many 6ohms tweeter nowadays.

if your speakers crossed high, it could have similar impedance (usually above 2-3khz the tweeter impedance are flat) assuming its well designed one.

[peterpan]

hiya batty,

 

I have 2 seas 6ohm metal dome tweeters that are sitting round doing f@@k all, and might be close. only issue one of the thin wires need to be resoldered but an able guy like you can fix it up in no time.

you are welcome to try them out and if they work out I am happy to donate them to you!

 

cheers

pete

[henry218]

hi peterpan,

which model ? if the previous vifa was textile, it may have diff sound, but sometimes it may be better afterall

cheers

henry

[Green Wagon]

I'd have a look at the crossover, see if there isn't a 'dropping' resistor in the tweeter circuit that can be altered.

[peterpan]

hi henry,

 

they have 25tac/dw I and h734 6ohm written on then, as far as I remember they were close to the metal dome vifas.

 

cheers

[Batty]

hi peterpan,

which model ? if the previous vifa was textile, it may have diff sound, but sometimes it may be better afterall

cheers

henry

Originals are metal dome

[Batty]

hiya batty,

 

I have 2 seas 6ohm metal dome tweeters that are sitting round doing f@@k all, and might be close. only issue one of the thin wires need to be resoldered but an able guy like you can fix it up in no time.

you are welcome to try them out and if they work out I am happy to donate them to you!

 

cheers

pete

That would be worth a try Pete

[peterpan]

"That would be worth a try Pete"

 

give me a call when you want to try them out,

 

cheers

[Batty]

Bit busy this weekend with gardening, will contact you soon.

Cheers

[ryzaa]

Hi Batty, I have a few tweeters that could work sitting around if you want to try them. 
SEAS T29CF002 [Crescendo]
Vifa XT25
I think I have a few others that may be suitable, I will have to check at a later point, but they include the Raal 70-10D, however I am waiting on some replacement ribbons for them

[henry218]

hi ryzaa,

sorry abit OT, what happened to the 70-10D?

cheers

henry

[Batty]

Hi Batty, I have a few tweeters that could work sitting around if you want to try them. 

SEAS T29CF002 [Crescendo]

Vifa XT25

I think I have a few others that may be suitable, I will have to check at a later point, but they include the Raal 70-10D, however I am waiting on some replacement ribbons for them

Also worth a try, thanks.

[Paul Spencer]

Do you realise that this means redesigning the tweeter crossover network?

[Batty]

I knew you would say that.

[ryzaa]

hi ryzaa,

sorry abit OT, what happened to the 70-10D?

cheers

henry

I think there may have been a fault in them, they started distorting at low volumes fairly soon after I had them running [active crossover, as well as 6db/octave at 2khz with a protection cap]. Pulled them apart to find the ribbon on one side was shorting out on something. 

[henry218]

for tweeter part, assuming similar impedance (crossed high at their comfortable range) you could get away with it.

unless crossed low (below 2khz, which I doubt since the d25 won't work well).

[hochopeper]

Arbitrarily swapping tweeters around isn't a great idea.

Comparison of efficiency needs caution too, for example a 4ohm driver rated at 2.83V/1m vs 8ohm driver at 1W/1m is a subtle but important difference. 2.83V into 8ohm is 1W, at 4ohm it is not. Efficiency spec of a passive speaker has even more complexity again.

Edited August 3, 2013 by hochopeper

[VanArn]

A candidate to consider as a replacement is the Peerless HDS 810921 , 8 Ohm nominal impedance and a sensitivity of 93 dB SPL . Also a Scan Speak D2608/913000 would suit the requirement of providing a little bit more treble for The Castle Howards (90  dB SPL  sensitivity).Usually the crossover network will need to be altered to achieve a smooth transition between the drivers and hopefully will only involve a change of resistor values  in an 'L' pad, if used in the tweeter cct.

[davewantsmoore]

Peerless HDS 810921

Scan Speak D2608/913000

 

They are actually exactly the same tweeter.   The HDS tweet got rebranded to ScanSpeak a few years back.

 

 

Batty.  If you tweeters are faulty, then replace them with the identical model.    Otherwise, connecting a different tweeter is 99% likely to make things "worse".    Post 16 and 20 are understatements if we are talking about good speakers.

[Batty]

I think I will leave them standard. I have lived with them since 1995, they can't be all that bad

[henry218]

Hi batty,

I just read again your post, did you change the original tweeters already? As the std tweeter was oem model with 91db.

http://www.solen.ca/pdf/vifa/d25ag0506.pdf

well if you did changed to the std d25 35 which is 89db, then we can find a more suitable ones for it.

Cheers

Henry

[Batty]

The original tweeters in my Castle Howard S1 is the Vifa D25AG, which I have replaced with the same tweeter.