B200 and Eminence Alpha-15A report ~

-Richard- · « **Reply #20 on:** 14 Nov 2007, 06:19 am »

Some of the specs of the 15" WARRIOR-15 are very interesting... they go lower than the Alpha's by quite a bit... the Alpha's only go to 46db with a Fs of 41. The Warrior's start at 35Hz. And they are cheaper. $45 compared to $60 for the Alpha's. I am actually tempted to buy a pair and see if I hear a difference given there lower range in the bass... they are s-o c-h-e-a-p! And 100db sensitivity!!!!!! Rather nice.

RMS Power Handling:    250 watts

TS Parameters
FS    36 hz
VAS    8.29
SD    143.13
Qts    0.826
Qes    0.888
Qms    11.83
BL    12.76
Re    6.40
Nominal Ohms    8
Le    468.73 uH
Mms    98.98
X max    0.25"
X mech    0.5"
Peak Power Handling:    500 watts
Ohms:    8
Frequency Response:    35 to 4600hz
Sensitivity:    100 dB
Magnet:    50 oz.
Basket:    Stamp
Voice Coil:    2.5" kapton
Cone:    Paper
Surround:    Accordion
Binding Posts:    Clip Type
Pole Piece:    .
Overall Diameter:    15 1/16"
Overall Depth:    5 5/8"
Mounting Diameter:    13 13/16"
Mounting Depth:    5 1/4"

Thanks JeffB for the suggestion and for sharing your current explorations with us.

Warm Regards ~ Richard

Victor · « **Reply #21 on:** 14 Nov 2007, 08:17 am »

But these woofers do have a lower qts, so the LF output will be less. You will need a larger baffle, or have to equalize them more to get the same output

-Richard- · « **Reply #22 on:** 14 Nov 2007, 08:34 am »

Victor: But these woofers do have a lower qts, so the LF output will be less. You will need a larger baffle, or have to equalize them more to get the same output.

Thanks, Victor... very important insight there. In that case I will stay with my Alpha's and make
my life a great deal easier for it. Here are other important insights from Scorpion and MJK.

Scorpion: The Alphas are specified down to 41 Hz now for fs, for music that will certainly be okay. The dipole drop is compensated quite a bit by a raised bass caused by the high Qts value.

MJK:For a driver with a lower Qts the roll off will start well above fs so a stated efficiency is an over estimate for low frequencies.

Warm Regards ~ Richard

Michael V · « **Reply #23 on:** 14 Nov 2007, 01:55 pm »

Yeah I could see this driver being part of a great system. I would worry about EQ'ing them for more extension, because their Xmax seems smallish.

Now a pair of them...

jkelly · « **Reply #24 on:** 15 Nov 2007, 12:15 pm »

Richard,

Do you have a link for the 4.70 copper coil inductor?
I'm not good at finding these things on the web.

Tnxs,

Jeff

Michael V · « **Reply #25 on:** 15 Nov 2007, 05:44 pm »

Jeff,

I'm obviously not Richard but here's the coil I'm using:

http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568

One drawback to the single coil crossover on the bass driver is you need a lot of millhenries, which means, especially with lower-quality coils, the DCR is much higher. I'd be curious if anybody has directly compared different units.

Regards
Mike

jkelly · « **Reply #26 on:** 15 Nov 2007, 10:13 pm »

Thanks Mike,

I noticed I have a pair of 12 mH inductors - probably from a subwoofer project.
Do you know what the cut off would be for 12's?

Jeff

-Richard- · « **Reply #27 on:** 17 Nov 2007, 04:50 am »

Hi JKelly ~

Looks like you found the inductor you need... great!!!!

I work with PartsExpress... if you ask for a technical adviser when you call and tell him what you have and what you are using it for they can "calculate" the information you need... I always found them extremely helpful.

http://www.partsexpress.com/index.cfm?raid=1&rak=parts_express

you could start here for inductors:

http://www.partsexpress.com/webpage.cfm?&WebPage_ID=3&Start=1&Filter=copper%2Binductors&searchorderby=1&sm=1&so=1&search_type=main&desc=ASC

then click on the upper right hand "page 1 of 8": 1,2,3 and so on to see all the inductor values with prices and pictures. If that link does not work look at the upper right hand area of the home page and see a thin rectangular box that says "Keyword or Part #"... type in "copper inductors" and then click on the red "go" oval to the right of it.

As far as copper coil inductors are concerned... there are 2 "schools" in audio... one school says that only "boutique" parts... parts that have superior spec's... can bring you close to the superior sound that is the actual potential inherent for each specific audio function... the other school shrugs its shoulders and says that as long as the parts meet the principal "value" that the audio function needs to perform efficiently it will take you were you want to go.

Most of the time I start at the "basic" parts concept and see how that sounds... although admittedly in my Peppard preamp I spent $400 more than I intended on "upgrades" in parts... on the advice of friends.

Warm Regards ~ Richard

opnly bafld · « **Reply #28 on:** 17 Nov 2007, 04:43 pm »

Quote from: jkelly on 15 Nov 2007, 10:13 pm

Thanks Mike,

I noticed I have a pair of 12 mH inductors - probably from a subwoofer project.
Do you know what the cut off would be for 12's?

Jeff

According to the PE chart: at 8 ohms the roll off would start a little above 100hz and at 4 ohms a little above 50hz.

jkelly · « **Reply #29 on:** 17 Nov 2007, 07:43 pm »

Thanks - that seems worth a try.

OK is the coil in series with one leg (positive)?

Jeff

TerryO · « **Reply #30 on:** 17 Nov 2007, 08:09 pm »

Quote from: Michael V on 15 Nov 2007, 05:44 pm

Jeff,

I'm obviously not Richard but here's the coil I'm using:

http://www.parts-express.com/pe/showdetl.cfm?vReviewRateForm=1&vReviewSource=E&orefer=reviewEmail&vReviewRand=440034440219&Partnumber=266-568

One drawback to the single coil crossover on the bass driver is you need a lot of millhenries, which means, especially with lower-quality coils, the DCR is much higher. I'd be curious if anybody has directly compared different units.

Regards
Mike

Mike,
Wouldn't the elevated DCR of the inductors also raise the Q of the woofers, giving somewhat increased bass performance?

I believe that this is quite often employed by designers to:
1. keep costs down
2. increase bass performance

As always, I may be mistaken.
Best Regards,
TerryO

opnly bafld · « **Reply #31 on:** 17 Nov 2007, 08:35 pm »

Quote from: jkelly on 17 Nov 2007, 07:43 pm

Thanks - that seems worth a try.

OK is the coil in series with one leg (positive)?

Jeff

Yes

jkelly · « **Reply #32 on:** 18 Nov 2007, 12:54 am »

OK making some progress.
I will most likely make new panels but wanted to see what the Alpha 15's can do.
Tomorrow I'll wire them up.

Jeff

-Richard- · « **Reply #33 on:** 18 Nov 2007, 02:39 am »

Hi Jeff ~

Very nice!!!!! I really like what appears to be a dark bluish-gray "finish"... goes well with the blackness of the drivers. You may find that you do not need quite so much height in the actual baffle from the top of the B200's to the top of the baffle. My B200's are only 4 inches away from the top... I would love to post images of my new baffles but I must confess I do not know how to mount images into a post.

Let us know how it all sounds once you have everything hooked up. Allow for at least 200 hours of burn-in for both drivers... especially the B200's before they begin to relax and open-up.

What CD/dac/universal player and amplification are you using?

Warm Regards ~ Richard

jkelly · « **Reply #34 on:** 21 Nov 2007, 05:51 am »

Just a quick update on my B200 and Alpha's project.
I have been on a bit of a journey this week.
First it took a bit of time to deal with taking the filter off the B200's.
I found it hard to lose that nice warm sound and hear the B200's wide open and hot.
Is that what they sounded like when I first got them?

Also I was playing the Alphas too loud like a kid with a new subwoofer.

The result was that all the magic was gone.

So after going through all my interconnects, speaker cables, power cords, amps
and toe in. I settled in on my Jolida 102b amp driving both the B200's open and the Alphas
with the 12MH coil (for now). The bass is there when it needs it but not overstating
it's welcome. I've gotten the warmth back and restored the detail that was missing
due to the filters on the B200's.

So I do have the 4.7 coils on order to get more of the Alpha into the mix, hopefully
I will have them for the weekend.

Right now, feeling much better and like the fuller sound.

Jeff

ttan98 · « **Reply #35 on:** 21 Nov 2007, 06:03 am »

Quote from: jkelly on 21 Nov 2007, 05:51 am

I settled in on my Jolida 102b amp driving both the B200's open and the Alphas
with the 12MH coil (for now). ......

So I do have the 4.7 coils on order to get more of the Alpha into the mix, hopefully
I will have them for the weekend.

Right now, feeling much better and like the fuller sound.

Jeff

A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.

this is useful, as you would not be keeping expensive inductors in boxes which you will never use.

-Richard- · « **Reply #36 on:** 21 Nov 2007, 06:20 am »

Hi JKelly ~

Your target inductor value is what I am currently working with... 4.70 inductor translates to a 275 cycles cross-over with a minus 6db per octave fade above that. The Alpha's in the same baffle with the B200's sounds seamless to me. I am also using the same amp/preamp for both speakers right now hooking them up in parallel.

I am most interested to read what you will hear when your new inductors arrive.
What CD player/dac/hard drive (whatever) are you currently using with your OB's? Keep in touch.

Warm Regards ~ Richard

Michael V · « **Reply #37 on:** 21 Nov 2007, 01:54 pm »

Quote from: ttan98 on 21 Nov 2007, 06:03 am

A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.

this is useful, as you would not be keeping expensive inductors in boxes which you will never use.

Great idea, thanks for posting that!

Best,
Mike

ttan98 · « **Reply #38 on:** 21 Nov 2007, 10:24 pm »

Quote from: Michael V on 21 Nov 2007, 01:54 pm

Quote from: ttan98 on 21 Nov 2007, 06:03 am

A good trick I read somewhere is to use a multitaps power transformer(cheap), that will give you various values of inductance, once you determine the value, then get a high quality type.

this is useful, as you would not be keeping expensive inductors in boxes which you will never use.

Great idea, thanks for posting that!

Best,
Mike

You are welcome, I learn many tricks/facts/ideas from visiting various forums, the key is to use those which apply to you. There are many people contributing for the benefit of people like us. I am just doing my part.

Some care must taken as some of them are not quite accurate/true/misleading.

Wind Chaser · « **Reply #39 on:** 21 Nov 2007, 10:39 pm »

Quote from: ttan98 on 21 Nov 2007, 10:24 pm

I learn many tricks/facts/ideas from visiting various forums, the key is to use those which apply to you. There are many people contributing for the benefit of people like us. I am just doing my part.

Some care must taken as some of them are not quite accurate/true/misleading.

How do you sort that out? You're stating there are ideas that are true and applicable to one's specific application. Okay, I can grasp that. But then for the benefit of others, how do you sort out the ideas that are true but not applicable to your specific situation vs. the ideas that are bogus?

John