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Plans:
I needed to do some R&R on my amps so i moved the ESLs out and substituted these
"tempoary" speakers. Ran them for a week from 2 NAIM 160s (1 channel/per
driver). Over that time the quite prominent upper-midrange honk (particularily noticable
on male voices) has slowly been dissappearing and these things are quite outstanding
(and even more so when you consider there are less than $100 CAD in bits).
For the longest while i used them with extra woofers (i just slid them in where my
ESLs were -- amps, XO, woofers and all), but lately have been using them FR -- i
am VERY impressed with the amount of bottom end those 4" drivers can put out
-- not anywhere near the equal of the Peerless, but their is a lifting of a bit of
a viel when i take the Marchand XO out of the path. They have no need for bafflestep
compensation since that is essentially dealt with by the rear facing driver.
I swapped out the NAIMs for a beater SE EL84 (the NAIMs are being tweaked). Lost
a bit in the highs and the amp struggles if i try to play too loud (~160 cu m room),
but they are very satisfying (really shows the exponential cost of small improvements
-- swapping out $1.5k CAD worth of used amps for one that cost $0.075K used).
The drivers have some ductseal on the baskets and are otherwise stock. I plan on
going thru a series of mods to them all the way out to phase plugs on the front driver.
And i have a spare set if this is too far. The cabinets are made from a variant of
baltic birch ply (swapped for a set of replacement drivers for the sales reps infinity
bookshelf speakers) with a layer of laminate. The felt ring is pretty, but i haven't
done any serious listening to differences with & without. Modifications &
tweaks have been slow coming -- these are suffering from being so enjoyable that
i haven't been keen on removing them long enuff to tweak them more. They benefit
from a little extra on the top above 10k and i have been trying out many tweeters.
I have stocked up on some more of these drivers -- i'd like to see if Martin's model
can show some room for improvement on the enclosures.
If anyone is any doubts about this combo, lay them aside. |
<cliking on most images will take you
to a larger one>
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Tweeter
of the Week
modified Foster alnico
50RT01 2" Cone
This is a Foster branded
-- probably the OEM for the Sony below -- version of the alnico 2" thimble tweeter.
I was quite impressed by the performance of these cheap tweeters (when i sell them
i get $2 USD). I removed the dust-cap & added a phase plug. I shortened a 3M
ear plug -- they are tapered and i had to make the base diameter a little smaller
(probably need to shorten it just a tad more and get the cut straight). I then crazy
glued a washer to the base of the plug and it is held in place magnetically. Initial
impressions are positive.
Almost every week it
seems i am passing thru another pair of interesting tweeters -- almost making a living
by recycling hifi gives me access to many different ones. These are all being used
as supertweeters with a nominal XO of 10k. None of the dogs make it onto these pages.
So far the Isophon
above is the standout, with the others coming really close. Of the ones below the
Coral domes & the shorter large Sansui & Foster tweeters (the latter not
pictured) have the edge -- i suspect due to better time alignment with the shallow
40-1197s.
Previous
Tweeters
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Foster
alnico 40-1166 2" Horn
This is the 3rd set
of these i have played with. They have a longer horn than the one's below. I positioned
them a bit forward from where i had them last time. The last couple weeks listening
conforms these as one of my 3 favorites, along with the Coral dome, and the Isophon
cone.
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Hitachi/Coral
Alnico 2" Horn
This is a very nice
looking cast metal horn with a very large alnico magnet. Labeled Hitachi, from the
evidence of the other speakers is probably a Coral OEM. Quite a bit too efficient
for the pipes i have added an l-pad to bring the levels down. These are right up
with the best tried yet.
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Alnico
Sony 2" cone
After the success of
the Isophon cone i thot i'd try some other small cones. After a couple that didn't
work out, i popped these on. They are quite good. Not up to the better ones that
preceeded it, but i'd say ahead of the ceramic Audax. What is neat about them is
that these are cheap, cheap. I have sold a number of pairs of almost identical Fosters
for 2-bucks! Future trials after some surgery and we will see if they get better
-- damar & a phase-plug (similar to what Dick Sequerra is doing with the tweeters
on his mini-monitors).
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Alnico
Isophon 2" cone with open back
Best to date.
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Foster alnico Horn
Tweeters
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Panasonic/Sansui T-60
alnico horn tweeters
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Panasonic/Sansui T-157
alnico horn tweeters
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Coral alnico 13mm dome
super tweeters
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Audax
14mm ceramic magnet tweeter
the
mess on the top are 6 caps and a set of clip-leads for adjusting XO point
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The
FE103A Pipes
These are Chris' plywood pipes with alnico
Foster FE103As. These are outstanding. The tweeters are Foster's very similar to
the Sony's above -- they are almost unnecessary. The XO point hasn't been finalized
yet but it looks like it will end up in the 13-15 kHz range.
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The
Red Pipes
At the same time Chris built my pipes he built himself
a pr of mdf pipes for himself. These use the same Audax 14mm dome as above, but in
a waveguide (mounted from behind the baffle) and are modified a bit to support the
grills. I don't think there is a whole lot of difference between the mdf and plywood
pipes, but Chris likes the plywood just a bit better. These are an example of how
not to paint mdf, the finish is pretty but prone to scuffing.
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The following is a post
from the Full-Range Forum:
Mr. Doppenberg's plan works, it really does. Last Friday I printed off the plans
and picked up 4 RS 40-1197's. Saturday I cut 18mm MDF, Sunday I glued the cabinets
together, installed terminal blocks, stuffed with some poly batten material, mounted
the speakers and fired them up. They sound amazingly good for speakers that ran me
perhaps $45 CAD each (including biscuits and glue). They definately lack wads of
bass, but on the other hand they have great presence and crispness. I have a pair
of JMLabs Profil 77's in one room and set the newly assembled TQWPs up against them.
My daughter (who is not shy to tell her old man when he's strayed from the proper
path) thought that the JMLabs sounded fuller and prefered them overall, but she did
allow that the TQWPs were brighter and to her ear more accurate on vocals. Then we
carted the homemades to another room where the standard speakers are a set of Paradigm
5's with a powered sub. This time, and this chagrins me no end given the $$ the Paradigms
cost, my daughter picked the TQWPs. No contest in her mind. Only when the Paradigms
were supplemented by the sub did she think they were even close to the TQWPs.
So to the newbies and fence sitters out there: if you have a Radio Shack in the area,
and you own a dust mask, are strong enough to man-handle a sheet of 18mm MDF, and
have enough clamps to squeeze the cabinets closed over glue joints, then give Mr.
Doppenberg's design a go.
Happy listening,
peter rogers |
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TNT
Audio Review of the ACR FE103 BD-Pipes
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