Author Topic: Fishing expedition: uses for Seas M15Ch-002  (Read 4214 times)

Offline Kemosabe

Fishing expedition: uses for Seas M15Ch-002
« on: November 17, 2011, 01:18:28 PM »
Hi
I am hoping to tap into your collective wisdom and experience...
Simple one actually - I have a pair of Seas M15Ch-002, they seem to have good potential,
there is a bit of a response anomaly mentioned in various places...however,
I have yet to see a use or an implementation in any design which looks promising.
Any suggestions? Would love to hear your inspirational ideas.
I have tried an aperiodic implementation ala Troels in one of his designs - not bad sounding but clearly the partners and crossover are critical elements.
PS: my room wont handle a massively wide baffle - i.e. OB designs not really viable for me.
Regards
Anthony
DIY hi-fi: the journey is the destination.

Offline JimGore

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #1 on: November 17, 2011, 01:39:09 PM »
How about an OB for the midrange and tweeter, but with a TQWT or bass reflex on the bass driver?  It would make the baffle nice and narrow.

Ian.

Offline chipwelder

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #2 on: November 17, 2011, 02:05:08 PM »
Ja, that non-reflective magnet assembly begs to be used in the open...
OK! I've had it! I don't give anymore Kharma. Kharma should work in mysterious ways...

Offline ViVoAudio

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #3 on: November 17, 2011, 03:02:25 PM »
How about an OB for the midrange and tweeter, but with a TQWT or bass reflex on the bass driver?  It would make the baffle nice and narrow.

Ian.

+1000
If its music you want to hear 
Location: Cape Town

Offline Kemosabe

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #4 on: November 17, 2011, 03:24:48 PM »
Ok - that's pretty much what I've tried
Aperiodic midrange (with reflectors deflecting the sound out the back) with a bass driver in a ported box. I wasnt blown away!
That's why I said choice of woofer and tweeter is critical as usual. Maybe the woofer I used was just not that suitable.
Ian as you know I am going to do TQWT with your high efficiency approach but clearly I am not going to mate any super efficient woofer to this midrange. I'd rather run your 12" 12w500 18 Sound with a horn tweeter in a TQWT and keep that whole design HE.
I am just pondering here whether there is some magic to be extracted from this midrange that I cannot get from a well executed 2 way? I think there might be potential but I might need 1 or 2 conventional 8"-10" woofers per side to pair with this midrange. I say 2 as I will need to bring the efficiency of the bass section up to the 89db level where the midrange operates.
Also this midrange is pricey! You're not going to use this beasty with a R250 tweeter. It needs some luxury lavished on it!?
But is it going to be worth the effort?
DIY hi-fi: the journey is the destination.

Offline Kemosabe

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #5 on: November 17, 2011, 03:26:20 PM »
I mean sensitivity not efficiency - excuse me.
DIY hi-fi: the journey is the destination.

Offline JimGore

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #6 on: November 17, 2011, 04:12:35 PM »
When building a speaker system, the quality of the drivers defines your baseline performance.

Next, we add things before, around, and after the driver which all impacts on it in some or other way.  Sometimes the impact is positive, but mostly the impact is negative.

Thus, the cabinet will change how a driver sounds in a very serious way.  A less optimal cabinet and damping can completely kill the midrange for instance.

Next, the crossover can make or break a speaker.  No matter how good a driver is, a less than optimal crossover can make it sound like the cheapest Chinese model you can find.

Finally, driver integration including individual transfer function, summed transfer function, phase shift, breakup nodes, filter slope, filter knee, power response, power compression, beaming, strain, and diffraction all play a role - each one doing its level best to degrade your speaker's ultimate performance.

Moral of the story - there are alot of things to consider, and being a little bit off on a number of these things will cause you to be underwhelmed. 

If you are still interested in this specific project I can always measure it up and do some crossover work for you - you may just be pleasantly surprised at the results.

Regards,
Ian.

Offline bbe22

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #7 on: November 17, 2011, 08:06:06 PM »
You're not going to use this beasty with a R250 tweeter
what drivers did you try before with the SEAS mid and how did you go about the rest of the design ? 
.......cheers
Brian

Offline Kemosabe

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #8 on: November 17, 2011, 10:18:49 PM »
Hi Brian

I tried it out with a 10" Seas aluminium driver (L26RFX/P)
Seas 27TBFC/G Tweeter & a Vifa tweeter DX25TG.
Both of those tweeters are pretty decent in their own right but cost wise and performance wise not up to the level of say a Seas Millenium.
On the other hand I know implementation is critical as Ian said and even the best equipment implemented badly will sound horrible or at least not reach full potential which I obviously agree with.
I placed the woofer in a ported 80 liter enclosure (it may have been 85l - I cant recall exactly or the exact tuning).
The box may not have been perfect but probably not too bad as I stole the box volume and tuning from a Tony Gee project and confirmed with some box software.
I tested the setup using a 3/4 way dbx crossover (4th order LR). Tried a number of crossover points.

I got it all sounding ok - but nothing to right home about.

Clearly a well designed crossover and properly braced box would help - no doubt. This was just a proof of concept to myself.

I am thinking a nextel mid may be better used with a nextel woofer of the same range? And a decent tweeter. But I am not getting much inspiration...yet.

Regards
Anthony
DIY hi-fi: the journey is the destination.

Offline Atjan

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #9 on: November 17, 2011, 11:21:04 PM »
This is a very sexy looking driver and needs to be seen as well as heard.
It's only hifi people....

Offline chipwelder

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #10 on: November 17, 2011, 11:55:29 PM »
The Nextel mid can work with a alu cone, if you can really kill the alu cone resonances... this is not easy... always like the look of the nextel cone specs
OK! I've had it! I don't give anymore Kharma. Kharma should work in mysterious ways...

Offline bbe22

Re: Fishing expedition: uses for Seas M15Ch-002
« Reply #11 on: November 18, 2011, 07:14:34 PM »
yup , me thinks a visit to Ian might be the next useful step  ;)