Which drivers for BFM designs?

Configuring your Home Theater
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mga2017
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Location: Santiago, chile

Which drivers for BFM designs?

#1 Post by mga2017 » Wed Dec 04, 2019 11:15 am

Hi,

I am new in the forum, but not kind of new in the DIY sound world... I've built some DIY speakers designs, but never a BFM design.

I do not live in USA so most of my build are with local sourced drivers (imported) and some I bought online.

Now I am looking to upgrade my little home theater setup, and I am willing to try a BFM design, but I don't know which to buy as I don't know which drivers are used and in consequence I don't know if I can get them locally... One thing is to import a tweeter or even a compression driver, but another thing is to import a 15" driver, that would cost an eye and a half on shipping and import duties...

So, I am interested in getting a nice speaker for left, center and right channels, most probably powered from a standard AVR. Listening levels are around 80-85db, so not reference level at all. I do have 2x 15" sealed subwoofers (Dayton Ultimax 15) so low extension is not essential. The room is not big at all, at around 1.000 cubic feet. Also, if there is a SW design that's fits the bill (no pun intended) is size and it has a better performance than a sealed box, I am also interested.

From the designs of BFM i assume I am looking for these designs:

-. SLA Hometheater
-. TLAH and TLAH Pro
-. Tuba 18
-. Table Tuba
-. Wedgehorn 6
-. Any other suggestion?

So, which drivers are recommended for these designs? Locally I can get some of Eminence, Faital, PRV, Celestion and B&C (although too expensive)

Thanks in advance for your help!

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Bill Fitzmaurice
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Re: Which drivers for BFM designs?

#2 Post by Bill Fitzmaurice » Wed Dec 04, 2019 11:37 am

While each plan lists suggested drivers you are not limited to them. What matters is the Thiele/Small specs and frequency response. The usable range of T/S specs and frequency response is listed in every plan, so you may choose from what's locally available to you. Speaking of locality, you shouldn't keep yours a secret. Other members close to you can't help you if they don't know they're close to you.
Beating a sealed sub isn't difficult. All of our horn loaded subs do. I don't see any application for Wedgehorn 6 in a home theater.

mga2017
Posts: 8
Joined: Thu May 04, 2017 9:12 am
Location: Santiago, chile

Re: Which drivers for BFM designs?

#3 Post by mga2017 » Wed Dec 04, 2019 12:57 pm

Bill Fitzmaurice wrote:
Wed Dec 04, 2019 11:37 am
While each plan lists suggested drivers you are not limited to them. What matters is the Thiele/Small specs and frequency response. The usable range of T/S specs and frequency response is listed in every plan, so you may choose from what's locally available to you. Speaking of locality, you shouldn't keep yours a secret. Other members close to you can't help you if they don't know they're close to you.
Beating a sealed sub isn't difficult. All of our horn loaded subs do. I don't see any application for Wedgehorn 6 in a home theater.
Bill,

thanks for your reply.

Not a secret at all! I live in Santiago, Chile and here there isn't much DIY audio community... maybe a little hifi-audiophile community but not much on the DIY world...

Anyways... I know that each plan have the recommended drivers, but that does not solve the problem that I need to buy the plans to know which drivers do I need. For example, the SLA HT use the Faital Pro 5FE120 right? (I know this because there is thread from you that states that change from the Eminence 6") but I can't get the 5FE120 locally, I might get the 5FE100 in Argentina (which means importing them), which has different T/S parameters (not by a big margin thou) but I don't know which tweeter is used.

Also, regarding the subwoofer, the Simplexx 15 is a sealed/ported so not much improvement from what I have, you would recommend going to a horn loaded one?

Thanks in advance!

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Tom Smit
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Re: Which drivers for BFM designs?

#4 Post by Tom Smit » Wed Dec 04, 2019 11:43 pm

mga2017 wrote:
Wed Dec 04, 2019 12:57 pm
Not a secret at all! I live in Santiago, Chile and ....
You can add this in your "profile" so that it will always appear when you post. Not everyone will look at this particular post to see where you live, so, if it's in your profile,whether you post now or later, others will see at a glance.
mga2017 wrote:
Wed Dec 04, 2019 12:57 pm
Also, regarding the subwoofer, the Simplexx 15 is a sealed/ported so not much improvement from what I have, you would recommend going to a horn loaded one?

Thanks in advance!
The THT isthe one to give you the most reward. That, and you could repurpose an Ultimax possibly.
TomS

Grant Bunter
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Location: Ilfracombe Queensland Australia
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Re: Which drivers for BFM designs?

#5 Post by Grant Bunter » Thu Dec 05, 2019 4:17 am

Hello, and welcome to the forum :)

It can be really difficult to take a leap of faith, and accept that Bill's designs work.
For the rest of us around the world, we see these crazy low prices for drivers that the US members just accept, and struggle to take that leap.
It is so worth it!
As long as you can find something near enough in terms of TS parameters ( within 10% will work), even if it's not perfect, it's still much cheaper, and often better performing, than local commercial equivalents.
And that, and building, is why you DIY.

So, keep asking questions until you have enough information so you can decide which plans to buy, buy the plans, source the drivers, ply, PL premium, screws etc.
Build the cabs.
Reap the benefits...
Built:
DR 250: x 2 (melded array) with March 2012 plans. 2 more under way with CD horn
T39's: 4 x 20" BP102 , 2 x 28" 3012lf.
WH8: x 3 with melded array.
Bunter's Audio and Lighting "like"s would be most appreciated...

mga2017
Posts: 8
Joined: Thu May 04, 2017 9:12 am
Location: Santiago, chile

Re: Which drivers for BFM designs?

#6 Post by mga2017 » Thu Dec 05, 2019 9:03 am

Thanks all for your replies...

So, back to getting close to the info I need for my L-C-R channels, it seems SLA HT and TLAH are the way to go, but I have some questions:

1-. My room is very small and the MLP is around 1.8 meters from L and R channels, and less to the center, and I've heard line arrays are only beneficial if the MLP is further than that distance.

2-. The TLAH Pro uses 8" drivers, but IDK the size of standard TLAH drivers, is it same as the SLA? (4" - 5" midbasses?)

With that info I can search for the available drivers and post the respective T/S to see if would work.

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Bill Fitzmaurice
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Re: Which drivers for BFM designs?

#7 Post by Bill Fitzmaurice » Thu Dec 05, 2019 11:53 am

TLAH and SLA use the same midbasses. You don't need TLAH in a room that small, use SLA. The recommended four inch midbass driver is the Goldwood GW-4028. For driver substitution acceptable T/S specs are Fs 80Hz-110Hz, Qts 0.6-1.1, minimum xmax 1mm, impedance 8 ohms. Vas is not important with drivers this small. There are many similar drivers out there, and many sources often have some on closeout. You may go smaller than a four inch if the specs are OK, but don’t go any larger with a round frame driver. You may go larger with a ‘pin cushion’ style squared-off frame, so long as the outside edge to edge dimension is not more that 4½ inches. Be sure your drivers are 8 ohms impedance, and have flat response to at least 6kHz.
The recommended tweeter is the Goldwood GT-302. For substitution use a ⅜ to ½ inch dome tweeter, with a frame no more than 2½ inches diameter. The tweeters must also be 8 ohms impedance. The recommended drivers as well as crossovers for them are available at www.speakerhardware.com.

mga2017
Posts: 8
Joined: Thu May 04, 2017 9:12 am
Location: Santiago, chile

Re: Which drivers for BFM designs?

#8 Post by mga2017 » Fri Dec 06, 2019 8:06 am

Bill Fitzmaurice wrote:
Thu Dec 05, 2019 11:53 am
TLAH and SLA use the same midbasses. You don't need TLAH in a room that small, use SLA. The recommended four inch midbass driver is the Goldwood GW-4028. For driver substitution acceptable T/S specs are Fs 80Hz-110Hz, Qts 0.6-1.1, minimum xmax 1mm, impedance 8 ohms. Vas is not important with drivers this small. There are many similar drivers out there, and many sources often have some on closeout. You may go smaller than a four inch if the specs are OK, but don’t go any larger with a round frame driver. You may go larger with a ‘pin cushion’ style squared-off frame, so long as the outside edge to edge dimension is not more that 4½ inches. Be sure your drivers are 8 ohms impedance, and have flat response to at least 6kHz.
The recommended tweeter is the Goldwood GT-302. For substitution use a ⅜ to ½ inch dome tweeter, with a frame no more than 2½ inches diameter. The tweeters must also be 8 ohms impedance. The recommended drivers as well as crossovers for them are available at www.speakerhardware.com.
Bill, thank you very much for your help and information!

I will search for 4" drivers here and in Argentina. I know in Argentina Faital Pro is available, but drivers are expensive and in an array cost can build up very quickly.

Thanks again, and I will keep you posted with my findings!

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Bill Fitzmaurice
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Re: Which drivers for BFM designs?

#9 Post by Bill Fitzmaurice » Fri Dec 06, 2019 8:12 am

You may find that even with shipping costs the drivers from speakerhardware.com are the least expensive choice.

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