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What woud you do with these drivers?

post #1 of 24
Thread Starter 
Hiya all,
Ive got a pair of pro studio speakers that just sound awsome, but have limited low end.
2 way speakers, audax tw034 tweeter and a volt b250.2 10 inch bass unit in a (approx) 8L ported cabinet.

(the inside pair in the picture)



http://www.voltloudspeakers.co.uk/Lo...dy_b250_2.html

http://www.audax-speaker.de/index.ph...ax-tw034x0.pdf

As this speaker really kicks arse, with a (to my ears) realy low distortion, good dynamics and tight sound compaired to other speakers ive owned, but is far too ugly and boring looking for my liking, I was thinking of doing somthing with them that would suit my home and requirements. My listening room is large (circa 150m3). Low distortion and low dynamic compression at reasonably high output is the aim.

I love the idea of digital active xo's such as mini dsp -but unfortunately, they will be used with lossless bluray much of the time and hence an analogue signal will only be available and im not to sure about converting from digital to analogue so many times

-Some food for thought-
Troels gravesens best sounding speaker (his own words) uses this tweeter with a waveguide which he supplies.
http://www.troelsgravesen.dk/JA8008_DTQWT.htm

The wife blew me away by saying she likes the look of Jack Bouska's ultimate speaker-
http://jgbouska.tripod.com/audio/



I dont want to start spending crazy money, as this design must have cost many thousands of GBP, but would love to attempt somthing like this in style at least, possibly with the second hand jbl pro audio drivers that are often available on fleabay. However I accept that the efficiency of the volt/audax drivers is much lower than the drivers listed on Jacks design. It seams the volt bass drivers are often matched with the atc mid dome (sm75s) Ive heard this driver and was mighty impressed, but its also very expensive.

http://www.audiosmile.com/forum/showthread.php?t=13825

a second volt b250.2 can be had for about £100, so a MTM could be possible.

Open to all ideas/suggestions?

What would you do?
post #2 of 24
Thread Starter 
some mid driver thoughts-

http://www.parts-express.com/pe/show...number=264-857

low efficiency,not sure about output limitations but mtm is poss- only the c-c distance would be an issue....hornloaded?...hmm.

http://www.parts-express.com/pe/show...number=294-651

driver measures well, would prefer lower qts though.

If I had the money!- http://www.usspeaker.com/bms%204592nd-1.htm
post #3 of 24
not really sure what you are asking.

the bouska design uses sealed woofers which will reduce your extension a lot. he handmade those waveguides btw. are you sure you are up to that?

i would suggest that you just find an enclosure that you like and either buy it or diy copy it. keep the internal volume the same and the same port length and number of ports as the one that you have now and you will be able to use the same drivers and crossover that you already have. porting out the back is one way to clean up the baffles btw. some absorption on the walls at the points of reflection will help with dialog intelligibility for movies.

here is just one of a million examples for inspiration.


LL
post #4 of 24
Thread Starter 
Hi LTDO2,
reboxing the speaker into a larger enclosure would increase the extention, and has the possibility to improve the looks, but the aim here is to change the design to a better one.
The woofer begins breakup around 800hz which is already pushing the tweeter. A FR test of the speaker at various output levels will likely show this. That aside, pushing the tweeter that low is going to push the distortion up and at a fairly critical midrange freq.
Baised on this, the first thing Im looking to do is add a mid driver to ease off the distortion in the mid band to low levels.

Taking the TB driver as an example,
http://www.audioheuristics.org/measu.../TB75/TB75.htm



Frequency response




although the drivers FR isnt idealy flat, which will present problems for the crossover, its use would be reasonable for between say 600 and 2khz. The similar material to the tweeter has a good shot at giving similar timbre carateristics, which is good, but the best part is the very low distortion this driver gives.
post #5 of 24
lbaccoustics, Your center channel and the outter L/R speakers look somehwat like the Adire Kit LCRs I based my front stage on. The inner L/R speakers you are posting about look more "pro audio" to me. Same or similar tweeter, but rather than 3 way with the midbass being small compared to the woofer on the 2 way, and the cone woofer looks like thin paper vs thick poly for the 3-ways. Hard to tell from the pic.
Jack Bouska's ultimate speaker looks like it could/should suffer from a little bit of comb filtering? It is the inverse to myt front stage, I have 4 midbass in the center, 2 midrange, the 4 tweeters spread in a strait line 49" wide looking very similar to "ultimate speaker ".
Looking at lbaccoustics links, the pro audio light paper coned accordion surrounded driver has a beastly motor and spider, a trend I have been noticing as I start to look at these other drivers that have an inferior appearance to me. Maybe this is where my misconceptions began, the fronts of the drivers look old fasioned, light weight, while the back side is beefed up...hence the high efficiency and warm sound?
LTD02's pics have the HT look... shiny plastic thick looking cones, thick rubber surrounds. Does this decrease efficiency?
Hope I didn't bother you too much with my OT... popping in to say i am watching your thread and hope to learn from it!
post #6 of 24
"the first thing Im looking to do is add a mid driver to ease off the distortion in the mid band to low levels."

oh, then you are talking about building your own speaker from the ground up. that is a big task.
post #7 of 24
Thread Starter 
Quote:
Originally Posted by kryptonitewhite View Post

lbaccoustics, Your center channel and the outter L/R speakers look somehwat like the Adire Kit LCRs I based my front stage on. The inner L/R speakers you are posting about look more "pro audio" to me. Same or similar tweeter, but rather than 3 way with the midbass being small compared to the woofer on the 2 way, and the cone woofer looks like thin paper vs thick poly for the 3-ways. Hard to tell from the pic.
Jack Bouska's ultimate speaker looks like it could/should suffer from a little bit of comb filtering? It is the inverse to myt front stage, I have 4 midbass in the center, 2 midrange, the 4 tweeters spread in a strait line 49" wide looking very similar to "ultimate speaker ".

Jacks speaker, like all d'appololito designs will suffer the reality of comb filtering - no doubt, this is a phase issue and is manifest as a slightly wobbily FR depending on the position you are listening from. The advantages of the design are that you can decrease all areas of distortion at any given output level, and also increase the headroom by 3db. The question is- how audiable is comb filtering? - as im listening from 4m+ away, the problem of comb filtering is much less for me, so this is an answer I dont feel I need to address in my home. (thankfully!) Spacing the drivers as close as possible is still a priority though.

The speakers on the outside of the photo are Troels Gravesens tjl3w speakers and use the one and only seas excel magnesium drivers and a hiquiphon ow1 tweeter. -they are good speakers, but the application is wrong for me. It took me a long long time to realy get a grip on what was realy wrong with these speakers and the answer is that its nowhere near optimal for the environment I use it in or what turned out to be my personal tastes. In fact, I could argue that it would be the wrong speaker for most environments.

I would imagine there are one or two who would read the last paragraph and think I was just plain wrong. How could such a perfectly measuring speaker be no good? everyone knows the seas excel drivers are some of the best money can buy ... right? Well, please read on and learn from my mistake!

The tjl3w's are maxed out at under 100db at 1m, the tweeter is the limiting factor and so this cannot be 'fixed' with crossing over to a sub. The speaker is 85db@1w so its rather ineffecient. This inefficiency cannot be overcome with power (that is a parasound halo a51 in the pic) because the more energy you introduce, the less efficient the driver becomes (power compression) and what happens is that you just dont get life and dynamics from the music! On top of that, there comes a taste factor- I like low qts drivers - plain and simple, a driver needs to be tight and not boomy. I appreciate that the box alignment and implimentation is key in getting this right, but for me sealed sounds wrong generally for me (so far!) and drivers that control there own movement sound closer to real. I can only apply this absolute to bass drivers as I havent had the chance to realy see what difference this makes to mids.
Basically, the tjl3w's lack bite when needed and are far too output limited. They are however realy quite special when brought close in to 1m- very detailed and spacious- but this only confirms the problems ive listed as the volume needed is very much lower at this distance.



Quote:


Looking at lbaccoustics links, the pro audio light paper coned accordion surrounded driver has a beastly motor and spider, a trend I have been noticing as I start to look at these other drivers that have an inferior appearance to me. Maybe this is where my misconceptions began, the fronts of the drivers look old fasioned, light weight, while the back side is beefed up...hence the high efficiency and warm sound?

The pro audio speaker has some very nice features that are not appreciated when you look at them. They go very loud cleanly, and although they have very limited bass and are ugly believe me when I say they are special. That tweeter is massive and by far the heavyest tweeter ive ever held. The waterfall graph of it shows just how good it is-



http://www.troelsgravesen.dk/TW034.htm

have a look at the impulse graph- tight no? These fabric tweeters have very little energy storage.

The bass driver is a paper coned heavyweight monster that surprisingly has quite a stiff cone and lots of headroom. Unsurprisingly to my ears, qts is a mere 0.2 - tight as a badgers arse. I dont get the 'airy' magic that seams to come from pistonic drivers like the excel units, but I get drama and dynamics in spades- but without too much loss of spacious 'out of the room' sound because the cone is still stiff- just damped well.

You mention 'warm sound' - Many paper drivers are indeed warm sounding.... but unfortunately this is actually a bad thing imo. It may sound pleasant, but its the sound of breakup where the cone is deforming in shape as it tries to keep up with the music waveform. This bass driver doesnt sound particularly warm. I can tell its paper- sure, as all cone materials have a signature of some sort ie -they break up in particular patterns. Many paper drivers (particularly full range) break up at all levels because in order to get the bandwidth of the driver so wide, the cone needs to weigh next to nothing therefore its as thin as possible- hence the particularly 'warm' sound.
. I dont particularly want to push any of my drivers anywhere near there limits for this reason (among others). Hopefully you can begin too see why I would consider Jacks design to be close to optimum for me.
To my ears, the speaker sounds a little forward- a negative that I associate with using a 10 inch bass driver all the way up to 1k+. The sound changes in the mid as I walk around the room- this is basically beaming and power response related so again somthing I would look to solve with adding a mid driver.

Could you post a pick of the adire speakers you mention?

Quote:


LTD02's pics have the HT look... shiny plastic thick looking cones, thick rubber surrounds. Does this decrease efficiency?
Hope I didn't bother you too much with my OT... popping in to say i am watching your thread and hope to learn from it!

Not in itself no. But as a generalisation - yes the majority of designs that have this aesthetic quality are lower efficiency yes. Cones are like cars- you only need 200hp to overcome the innertia of a aluminium kit car for some serious speed, but you would need 2,000 hp to make a hummer realy shift. The stiffness to weight of the cone is very important, thats again why the seas magnesium drivers are so good- magnesium is very stiff- but its still to heavy to shift! Berlyium is the ultimate in this area. In reality, its not that simple though- The reality is that the cone, however hard -will deform-(brakeup) and when this happens, the harder and less damped the material, the worse it sounds. Play a typical cheap 1 inch aluminium tweeter too loud or low and you will know what I mean. This brings you back to paper- its very stiff for its weight, but the breakup is almost pleasant!.

ps- OT all you like as long as it benifits someone, its all good!
post #8 of 24
lbaccoustics thanks for taking oyur time for your reply! I have been of the oppisite end of the spectrum wanting my drivers as loose as possible, but I find myself roaming wanting to investigate the other extreme.

I just googled and clicked images for links to exhisting pics for now, my photobucket runs very slow lately.


Extremis:

http://www.diyaudio.com/forums/swap-...pair-sale.html

http://www.diymobileaudio.com/forum/...sion-pair.html

CSS FR125S:

http://www.vikash.info/audio/FR125S/

Vifa XT25TG30

https://www.madisound.com/store/prod...oducts_id=1181



I am heading outside, dragging the computer with me, and running some REW sweeps...I'll start a new thread of it, the old is exhausted. BTW... the Blue Print Audio 1803s I have for the substage, I am ordering recone kits with 3 or 4 spiders to stiffen them up... it is the beginning of that journey for me!
post #9 of 24
Thread Starter 
Quote:
Originally Posted by kryptonitewhite View Post

lbaccoustics thanks for taking oyur time for your reply! I have been of the oppisite end of the spectrum wanting my drivers as loose as possible, but I find myself roaming wanting to investigate the other extreme.

I just googled and clicked images for links to exhisting pics for now, my photobucket runs very slow lately.


Extremis:

http://www.diyaudio.com/forums/swap-...pair-sale.html

http://www.diymobileaudio.com/forum/...sion-pair.html

CSS FR125S:

http://www.vikash.info/audio/FR125S/

Vifa XT25TG30

https://www.madisound.com/store/prod...oducts_id=1181



I am heading outside, dragging the computer with me, and running some REW sweeps...I'll start a new thread of it, the old is exhausted. BTW... the Blue Print Audio 1803s I have for the substage, I am ordering recone kits with 3 or 4 spiders to stiffen them up... it is the beginning of that journey for me!

Sounds like a interesting project- the xbl2 tech is really somthing- I would love to have somthing like the css 4inch driver linked to but with a 0.2qts and paper or sandwich cone.

The vifa xt's are a nice little tweeter, I have used them several times in projects- amazing vfm!

Ive been looking for more candidates for mid drivers- this is tricky as it seams options that fit the band I want along with the output are thin on the ground.

http://www.aespeakers.com/phpbb2/vie...hp?f=15&t=2576

The ae td6m is a possible candidate- though again not perfect as it seams more suited to active crossovers due to the 7db or so dip on axis- the efficiency of the driver is more than enough to absorb the loss of filtering the dip out while keeping the output inline with the tweeter and bass. Inductance is uber low, qts would need a sealed box for me to get the tight sound im after- however, It may be posssible to specify a tighter spider for lower qts. Generaly it seams a well designed motor.
post #10 of 24
Thread Starter 
Ok,
I decided to get going on a few things with this, So Ive got a pair of JBL 2452H coming.

http://www.audioheritage.org/vbullet...21706-2452h-sl

The first thing that will need doing is either swapping the diaphram over from the TI ones to radian/truextent etc or aquaplas coated ones known as the 'SL' versions.

I also need to find me a horn...a BIG horn. Its gotta be conical (for the misses). At the moment, I need to gather all the data I can on FR's of different horn profiles with the JBL 4" drivers.

http://www.diysoundgroup.com/WaveGuides.htm

Hmmm, interesting!
Somthing like the JMLC 350 would do nicely, but I dont know how it will respond with this driver, any info/advice on this welcome!

The aim for this driver (and horn) is to cover the critical midrange- approximately 500hz to 7khz.
post #11 of 24
When you posted JBL 4" drivers, I assume you are actually talking about JBL CDs with 1.5" throats. I think you might be confusing the 4" diaphram with throat exit size. When we discuss CDs we general use the Exit size to reference them. Im not sure a 1.5" CD will play well enough down to 500Hz.



FWIW, I went to large horn designs, started planning last year. Im using IWATA-300s and I love them. I have the JBL 2445s with 2" throats (From MK). I also have the BMS 4590 and TAD 4001s so I have all the best 2" CDs you can own.


The JBL 2445 was not on pair with the BMS or TAD so maybe upgrading the diaphram could help it like what you are going to do with yours.
post #12 of 24
i can't say that i've seen a horn where the 2452/-sl was a fail. it is a very nice driver (jbl's top of the line p.a. c.d.). i would expect great results on most any good horn, but 500hz is really pushing it.

the lowest that i have seen a 1.5" driver crossed in a high spl application is the jbl 4722 cinema speaker, where the 2432 is actively crossed to the woofer at 630hz.

http://www.jblpro.com/catalog/suppor...pe=3&docid=621

you may also wish to consider that horn, as it is a pretty nice design.

with the big horn and the low crossover point, there is almost a perfectly smooth increasing directivity index.

in any case, it may be worth trying to dig up the raw response of the driver on that horn (zilch or somebody at audioheritage may have measured it) and then you will have some idea of what kind of e.q. you can reasonably apply to what you have.
post #13 of 24
Thread Starter 
Quote:
Originally Posted by penngray View Post

When you posted JBL 4" drivers, I assume you are actually talking about JBL CDs with 1.5" throats. I think you might be confusing the 4" diaphram with throat exit size. When we discuss CDs we general use the Exit size to reference them. Im not sure a 1.5" CD will play well enough down to 500Hz.

Yes, I didnt know how to put it. Some of the smaller 3" dia drivers are on 1.5" throats too, so I put it as 4".


Quote:
The JBL 2445 was not on pair with the BMS or TAD so maybe upgrading the diaphram could help it like what you are going to do with yours.[/

Subjective opinions suggest it battles the metalic sound of the dia, measurements show it lowers 3rd order harmonic distortion a bit. Good old zilch tested this some time back.

Quote:
FWIW, I went to large horn designs, started planning last year. Im using IWATA-300s and I love them. I have the JBL 2445s with 2" throats (From MK). I also have the BMS 4590 and TAD 4001s so I have all the best 2" CDs you can own.

The availability of the driver second hand means its an option where the TAD and BMS simply were not, so for me there was no point in worrying about it. You wouldnt have any measurements of your drivers on the IWATA horns would you?

Quote:
i can't say that i've seen a horn where the 2452/-sl was a fail. it is a very nice driver (jbl's top of the line p.a. c.d.). i would expect great results on most any good horn, but 500hz is really pushing it.

Thats nice to hear! Yes 500hz is pushing. Im not saying that I will end up down there as idealy you should crossover at double the horn resonance freq to get a good sound (according to JMLC) so 700hz for the 350hz jmlc horn, but Its not a critical problem unless the bass driver is very bandwidth limited- which is unlikely given my preferences.
As much of the critical mid as reasonably possible is the design aim
Unfortunatly the horn you link to wont be an option as for aesthetic reasons, I need a 'stand alone' conical horn.

What I would really like is a measurement of a jbl 24xx driver on a large scale conical horn- pref a JMLC, but thats going to be as likely as rocking horse poo I think.

*update*
I found this on the Jbl website-
http://www.jblpro.com/pages/components/23525354.htm



I cannot be sure, but it seams to suggest its a 630hz horn. however on the last page, it recommends lowest crossover of 500hz 18db/oct- which pleases me muchly

Its a good start!

One other thing I need to get to the bottom of is the throat entrance angle- the 2252 is 10 degrees, but just how important is it to match the horn to that?.
post #14 of 24
Thread Starter 
Update,

weighing all the options up, I gave in on going up to 15" on the bass driver.

So I have a fine pair of JBL 2226h 15" drivers on the way!



On the throat angle question, It turns out that the angle is 0 degrees for the 2452 driver, so I will be getting the 2" throat horn from auto-tech and turning an adapter to get the flare rate angle correct to the 1.5" 2452 driver, as I don't want to ruin the conversion from flat wave front to dome/spherical.
post #15 of 24
Thread Starter 
Ok, Ive got all drivers and REW up and working.

What do you guys suggest for crossover simulation/calculation to use with REW measurements?
post #16 of 24
Can you output a txt file from REW? Maybe Jeff Bagby's PCD. It's what I use. It takes some orienting though. It's really a minimum phase modeling program more than anything.
post #17 of 24
Thread Starter 
Ill have a look at that-
The design will likely be digital active, so Im not going to need component values, rather the topologies and freqs, group delay and phase.

In the mean time, post 22 in the following thread shows what the plan is with the crossover.
http://www.avsforum.com/avs-vb/showt...3#post21030013
post #18 of 24
Thread Starter 
Ok,

Time for an update!

The 2452H drivers have a nice pair of JMLC 350hz horns on there way to me biggrin.gif

The 2226 drivers have been sold (too big)

and I cant decide on a suitable replacement! I would like a 10" driver, but could possibly accept a 12" if I had to.
many choices, big lack of proper test data!

The TD10m is the obvious choice, but its mega pricey to get it over to the UK.

an audiofire 12 channel DAC is sat on the floor for the active crossovers... yum!
post #19 of 24
have you looked into the 18sounds driver lineup?

a pair of side-by-side 8nmb420's might be just what you are looking for.
post #20 of 24
Quote:
Originally Posted by LTD02 View Post

have you looked into the 18sounds driver lineup?
a pair of side-by-side 8nmb420's might be just what you are looking for.

I don't mean to thread jack but...
Speaking of 18sound, have you ever seen this?

http://www.eighteensound.it/staticContent/applications/kits/18Sound_kit15.pdf

I saw the "kits" on their website, having just built the 4Pi's I found this interesting.
post #21 of 24
Quote:
Originally Posted by lbaccoustics View Post

Ok,
Time for an update!
The 2452H drivers have a nice pair of JMLC 350hz horns on there way to me biggrin.gif
The 2226 drivers have been sold (too big)
and I cant decide on a suitable replacement! I would like a 10" driver, but could possibly accept a 12" if I had to.
many choices, big lack of proper test data!
The TD10m is the obvious choice, but its mega pricey to get it over to the UK.
an audiofire 12 channel DAC is sat on the floor for the active crossovers... yum!

So let me get this straight, (I am new to this and am trying to decide on a build for myself using similar drivers/horns), you are using the JBL 2452H drivers matted with the JMLC 350 horns for the Mid and High frequencys and you are using some, yet to be decided, 10" or 12" driver for the Low frequencies? Are you going to be purchasing a tweeter and horn combo for the High frequencies as well, or, are you going to use the the 2452H/JMLC-350's for both the mids and highs? 2 ways or 3 ways?

How would a Radian 950PB with an upgraded Truextent diaphragm work in place of the 2452H/JMLC-350? What would be a good horn for the Radian? How would the Radian 950PB in stock form compare to the JBL 2452H's?
post #22 of 24
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

have you looked into the 18sounds driver lineup?
a pair of side-by-side 8nmb420's might be just what you are looking for.

The big brother to the 8nmb420, the 10nmb420 is a serious contender, good extension, low low Le, neo motor etc, but - no distortion data! This seams to be the problem with 18sounds in general- I just cant find any independent data! Ive been going round in circles for weeks on this. The best I can do for this is to look at the 12NDA520 that Brandon tested in the drivervault-

https://sites.google.com/site/drivervault/driver-measurements/tang-band-75-1558se/18-sound-12nda520/non-linear-distortion

With the lambda clearly measuring the best, the 12nda520 (AIC) is the best of the rest Imo.

Other options include- the beyma 10g40, 10mi100 and unsual choices like the JBL e110, and 2012h

A nice second hand pair of lambda TD10m's would solve all this, but it seams people just don't want to sell them! smile.gif

Quote:
Originally Posted by Martycool007 View Post

So let me get this straight, (I am new to this and am trying to decide on a build for myself using similar drivers/horns), you are using the JBL 2452H drivers matted with the JMLC 350 horns for the Mid and High frequencys and you are using some, yet to be decided, 10" or 12" driver for the Low frequencies? Are you going to be purchasing a tweeter and horn combo for the High frequencies as well, or, are you going to use the the 2452H/JMLC-350's for both the mids and highs? 2 ways or 3 ways?
How would a Radian 950PB with an upgraded Truextent diaphragm work in place of the 2452H/JMLC-350? What would be a good horn for the Radian? How would the Radian 950PB in stock form compare to the JBL 2452H's?

It will be a 2 way for now. The 2452H is good out into the treble. The original idea was to have a single top quality driver cover the critical mid-range frequencies (700-7khz) which is more than covered by the horn in this design.
The radian is a great driver, though I'm not sure I would go with the tru-extent phram myself. If I remember correctly, the phrams are interchangable between the radian and JBL 2452?? If so, my preferred choice would be the 2452SL phram, as it measures the best if I remember correctly.

As for horns for the radian..... thats a can of worms that one!
In my opinion, what matters most is that the exit angle of the driver and throat are matched. This is why the JMLC horn I have coming has a 2" throat and a 1.5" exit driver- so I can make an adapter to change the throat angle of the horn to match the exit angle of the driver. This in my experience, along with poorly aligned positioning of the driver on the horn flange is the reason for much of the 'honk' sound many associate with horns.

I have no distortion or other measurement data on the radian, but I have heard many compression drivers, and the 950pb is one of the best- regardless of cost. It is truly lovely!
post #23 of 24
"This seams to be the problem with 18sounds in general..."

the 12nmb420 has a copper sleeve in the gap and a dead flat frequency response. i would expect that its distortion numbers are about as good as it gets. i'm not sure if that is better than aic or not.

this paper has some distortion plots for various designs.

http://www.eighteensound.com/staticContent/technologies/products/aic.pdf

the 4pi space frequency response is also a little confusing to folks who don't understand that a good chunk of the rolloff from 100hz up to 500hz is baffle step.

edit: the impedance sweep is almost flat to 10khz, which suggests the inductance is extremely well controlled even better than the full pole copper sleeve in the td12m which rises to around 22 ohms at 10 khz at drivervault.
Edited by LTD02 - 11/13/12 at 10:04pm
post #24 of 24
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

"This seams to be the problem with 18sounds in general..."
the 12nmb420 has a copper sleeve in the gap and a dead flat frequency response. i would expect that its distortion numbers are about as good as it gets. i'm not sure if that is better than aic or not.
this paper has some distortion plots for various designs.
http://www.eighteensound.com/staticContent/technologies/products/aic.pdf
the 4pi space frequency response is also a little confusing to folks who don't understand that a good chunk of the rolloff from 100hz up to 500hz is baffle step.
edit: the impedance sweep is almost flat to 10khz, which suggests the inductance is extremely well controlled even better than the full pole copper sleeve in the td12m which rises to around 22 ohms at 10 khz at drivervault.

Thankyou for the AIC write up link- I found it very interesting.

Ok, so I'm still undecided, - I like the look of the data on the AIC drivers, enough to buy some at a reasonable price, but it seams that they arn't the best value for money- coming in at over £400 a pair to me in the UK- vs aprox £700 for a pair of ae td10m drivers from the states and a waiting time as long as my inbred cousins left arm. Besides this, it now seams unlikely to find anywhere with some in stock- not as rare as rocking horse poo- but certainly as rare as a chicken with both its nuggets.

Its not inspiring to say the least!

The non AIC version driver (10NMB420) is a comparative steal at £200 a pair, - I could run 2 per side and get an extra large Christmas turkey this year to boot + grandma can get pi**ed on the sherry, which is always entertaining and worth at least 3db lower mid-band distortion in its own right.

Having looked at everything, at this point, I think its down to these 2 non- options and a third non-optimal option.


-In conclusion, unless a second hand pair of td10m's turn up- I think gran might need the walking frame:)
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AVS › AVS Forum › Audio › DIY Speakers and Subs › What woud you do with these drivers?