Drivers for IPL S3TL

[nippontiger]

Hi, this is my first post here, hope someone can give me some advice!
A few years ago, back in England I built an IPL S3TL transmission line using the kit from www.iplacoustics.co.uk. Unfortunately, I went through two or three of the main drivers (maybe by getting a bit carried away and playing too loud!!?).
I now live in Japan and would like to build some new speakers - I only have room for bookshelf speakers, but would like to choose a design whereby I could use the main drivers in my S3TL kit when/if I eventually move back to England.
The drivers in the S3TLs were the 180pp advanced polypropyene with the specs shown here : http://www.iplacoustics.co.uk/ipl_drive_units_.htm
I was thinking of making one of the following kits - the Zaph Audio SR71 http://www.madisound.com/catalog/pro...oducts_id=8306
or the Usher 701 http://www.partsexpress.com/projects...r701/index.cfm
Basically, would it be possible to use the Usher 8945A driver or the Seas ER18RNX in my IPL S3TL kit as a drop in replacement for the 180pp (I dont know enough to make a full crossover redesign.) based on the drivers specs - (I compared the VAS, FAR, QTS and they seem pretty similar.) or is it (as I imagine), a lot more complicated than that! Im afraid I dont have the dimensions of the S3TL here in Japan.
The IPLs sound fantastic by the way - I had a similarly priced pair of B+W DM601s before I built them and the difference was huge!
Thanks in advance for any suggestions!

[sreten]

Hi,

The short answer is it is not a lot more complicated than that
as long as the driver parameters are very nearly similar.
The stuffing can always be adjusted somewhat.
But note the IPL driver inversion .....

http://www.geocities.com/woove99/Spk...Usher_2way.htm

also see :
http://www.geocities.com/woove99/Spk...Usher_701.htm#

and :
http://www.geocities.com/woove99/Spk...18RNX_2Way.htm

/sreten.

[nippontiger]

Thanks for the reply! I think I will probably go with a design using the seas driver as it has very good power handling and the specs are very close to the S3TL driver. I read elsewhere that someone else had the same problem with the IPL advanced polypropylene driver - perhaps this custom built driver was a faulty design - although I played them quite loud at times in my small room, I never had the volume even up to half way on my 40 watt Rotel RA01 amp.

[Mike C]

Hi,
I had IPL S3TLs, 1992 version with doped paper cone bass driver and fabric dome tweeter (H400, H398, something like that).
They were very good speakers. I used a Naim amp, then a 45wpc el34 valve push-pull amp, then finally a 300B SET valve amp of 7 watts. They definitely sounded best with the 300B amp, though not a perfect match.

However, I reckoned I could get better from the best modern drivers, and above all I wanted higher sensitivity for good results using the 300B SET amp. Severe size constraints made me look into MTM's using 6.5 inch drivers. I first looked into Zaph's large MTM with Vifa XG18 or XT18; but with a lot of great help from Jay I ended up designing an MTM bass reflex with Seas ER18RNX and 27TDFC.

These are *superb* speakers. A significant improvement over the IPL's. Extra clarity and detail, and these are presented smoothly and gracefully. I don't mean smoothed over - they have bite and they rock, if that's in the music. Better dynamics than the IPLs generally, and especially in the bass. I was pleasantly surprised by that, as the IPLs have very good bass; but these have a very tuneful bass very similar to the TLs, well defined, about as low - with significantly more impact if that's in the music.
Tonality is excellent. Vocals are superb, and in particular female vocals transport me to musical heaven!!! All these things are definite improvements over the IPLs.

Now you may not get all of that from the single bass driver version (SR71, or similar design by Jay on his site). But you will get all the important things! If you have adequate amp power you won't need the second driver; I only have it to get more sensitivity.

I'm sure you'll love the design with the Seas drivers; go for it. If the bass reflex alignment works out well, you might find no need to put the drivers in the IPL.

If you get back to the UK, you're welcome to a listen.

[nippontiger]

Thanks for the reply. I was going to go with the seas kit but in the end I built a pair of the Usher 701 speakers, as I managed to get hold of the Usher 8945a main drivers for 6000 yen a PAIR- about 30 pounds! The seas drivers were 24000 yen each here - about 120 pounds, which was more than I wanted to spend. I reckon I'd like to go with some seas drivers in a future project - maybe a new pair of TLs as I really liked the bass from the IPLs. I like the look of the seas thor kit, but a bit too big and a bit too pricey for me right now!