Help with cleaning up decision appreciated..

[w_oswald]

Hi, all!
I recently "scored" a pair of AKAI JetStream speakers (without being able to test them first). Cabinets are of the "tunnel reflex" or "labyrinth" style, but their construction necessitated serious damage to open them. No loss - I was after the drivers anyway. The resulting prize:

AKAI 0.jpg AKAI 1.jpgAKAI 2.jpg

They are 5 inches diameter outside of basket. They look nice to me - reminiscent of some full-range drivers made by Fostex, perhaps? Unfortunately, despite outwardly pristine condition, these both have destroyed voice coils.
My questions:
1) Are these decent drivers (when functional); perhaps someone would venture a comparison to a better-known driver?
2) If answer to (1) is "yes" or "maybe", then what is the practicality of repairing these? I imagine a full recone kit would be required, and maybe that would be impossible to obtain and/or not worth the cost?

Just checking before I go to the trouble of sending them to the e-waste stream. (No, that doesn't mean pitching them into the river out back )
Thanks,
Wilf

[Nanook]

System 1 way, 1 speaker, and special back load system -
Book shelf type
Use unit For [ all the ] zones: 10cm corn type
Frequency response 50Hz - 17000Hz
The maximum input 10W (music power)
Impedance 8ohms
Output sound pressure level 95dB/W/50cm
Dimensions Width 140x height 365x depth of 270mm
Weight 2.9kg
Attachment Speaker cord (3.6m)

not sure of the quality, but they certainly have promise"

What I could find out about the drivers point to them being a clone of FE103 or a Foster 10F3 alnico.

so if they seem OK, I think worth the time.

[w_oswald]

Thanks for the info, Stew!

That cabinet sketch does look like the ones I got. The input connection was via 1/4" phone jack mounted on that little nameplate glued into the back of the cabinet, so not readily field tested without the needed plug. To access the drivers, I had to pry off some glued-on plastic trim strips on the front, remove some screws underneath, and then pry off the glued-on aluminum sheet covering the entire front panel. This exposed the mounting screws for the wooden front panel; removing that baffle finally allowed access to the driver mounting nuts.

So, does anyone know if there's a recone kit available somewhere for these? Otherwise, I guess we can only note that said speaker systems have nice drivers (in case one should ever come across a working pair), and toss these out?

Thanks,
Wilf

[Nanook]

Fostex FF125K fullrangers @$80/pr if you want something similar. At that price it would be hard to justify reconing your drivers, even if you could find a kit.

For a few dollars more (sounds like a movie title ), planet10-hifi has the Mark Audio CHR70eN drivers for $125/pr. Please see the application thread here at diyaudio. Well worth the $$$ (well I personally think worth more). Dave also has other drivers available and depending on the enclosure type and amplifier type may have a different recommendation.

Wilf, what equipment do you have? Fullrangers are at their best being driven by low powered, low dampening factor amplifiers. Have a look Current Source Amplifiers and Full Range Drivers. A very good explanation and comparison of many popular drivers.

Sorry if I am assuming that you are a "newbie". I see from your profile that you are a mechanical engineer, so certainly have a strong mathematics background. I like old things too (fixing 'em). This may be a new area of endeavor for you, and I think I've pointed you to a couple of good resources.

hmm "the wet part". Here in Southern Alberta we've been receiving record rainfall(my basement has been flooding continuously for the last 3 weeks or so, due to the rise of the water table). Lots of seeding is not done, nor will it get done. I'm thinking you must be in Winterpeg, or at least adjacent to the red River. What about Southwest Saskatchewan/Southeast Alberta?

[w_oswald]

Hi, Stew:

Hope you haven't had critical damage/losses from the basement flooding! Looks like a lot of us all across the prairies are in the same boat - not good, for sure. We are not far from Winnipeg, on a little river called "Seine". While in summer you often can't get far along it even in a canoe, it has recently been at flood level approaching the highest spring thaw in quite a few years. For us, just an inconvenience (so far).

Thanks a lot for the good reference links. This will take some time for me to digest (56 pages for the application thread!) I sometimes feel overwhelmed by the expanse of information available on the web, to the point where I need to take a break from studying and get on with designing & building some speakers! It's also easy to be humbled or even discouraged by all the examples of amazing designs and craftsmanship showcased by their (rightfully) proud creators.

No apology necessary; but I definitely don't consider myself a "newbie". "Slow Leaner" might be more appropriate - I've been hobbying around with audio for oh, a half century or so. Built my first (and only - mono) tube amplifier from a kit in junior high shops - it didn't impress me much, and I soon ditched it, heading down the solid-state/stereophonic path instead. If only I'd had a good full-range driver at the time - how differently things might have turned out!

So:

The solid-state guy probably starts fixing the response with a parametric equalizer, and the tube guy enjoys his music with a nice glass of wine.

Not having a parametric equalizer, I've sometimes found that a bigger glass of wine can be substituted to good effect. Seriously though, is tube amplification the only way to get decent performance out of full-range speakers? My various music playback systems (stereo) seem destined to be eternal works-in-progress - and with apologies for evading your question - perhaps better discussed at another time.

I have an interest in improving the sound of some TV equipment, and thought that some little full-range drivers (like these) in decently-designed enclosures might fit the bill. We have a 'not ancient' 20" flat-screen CRT TV with stereo sound, and despite making a decent picture, the sound quality is abysmal! Also, we recently upgraded my Mom's TV to a 26" HD LCD, and the audio is a big step backwards from her old mono Zenith CRT set. I was hoping to make some necessarily small bookshelf speakers or a single low-profile 2-speaker cabinet for each of these - hopefully without added amplification - just tapping into the TVs' speaker outputs. (Sorry if this isn't the lofty purpose you may have imagined I had.)

I already have a pair of (working) Fostex FE103a drivers, and after soliciting recommendations from this group in a previous thread, have plans to build them some Aiko Nagaoka-Style DoubleHorns. These would nicely flank our 51" rear-projection CRT-based HDTV. I also have a single Wharfedale Super 8 RS/DD that I hoped to fit as a centre channel. These would all be driven by a modest solid-state 5.1 Surround Receiver. Do you think I'm completely off-track with this?

Regards,
Wilf

[Nanook]

Wilf, I did assume you are technically proficient though.

Thanks for the "water well wishes", seems Maple Creek (Sask.) and Medicine Hat (Alta) and everything in between is getting really hard hit. It is an inconvenience to us, not really damaging, more of a nuisance here too.

Trust me that Dave's designs are excellent, and his excellent box library is a huge resource. The CHR70 thread is huge. I'd suggest that you skim over it until you hit some useful information. But, as I noted, at $125/pair, the current CHR70eNs are a bargain. And in addition Mark Audio has some designs that work well (obviously).

You certainly can design your own enclosures, but I like having the benefit of the experience of others. In the case of the CHR70eN drivers, I have used them to good effect in Dave's commercial design for them (I was a beta builder and tester), and in some small (15.5" X 18") OBs--but you need bass augmentation in this case. In the case of the boxes, they are pretty incredible, capable of significant bass (45ish Hz), with considerable output. 9mm peak to peak excursion helps. A local dealer heard them and dropped his jaw...