What would you do with these 10 " woofers if you would be me ?

[kanaddict]

The question is not how low they go, but how low loudly.

The twin focals will reach the 20s, but not really with enough volume to run them full range, especially with the active EQ I use, I needed the twin Adire DPL12s for that.

I would say a single Focal might get you to 40Hz if you weren't going especial loud. Steve

😕 Sorry if I was not clear in my post, but I was not asking how low the Focal can go, I was asking about the SEAS mid/woofer. I was wondering if one SEAS used on an open baffle could make it to let say 50 HZ. It could be interesting for me to try an open baffle for the mid/woofer and tweeter and use the focal in a TL configuration (tube or not).

regards,

 

[sfdoddsy]

Sorry I misunderstood, but the answer is probably not. I have tried the Seas mids down lower than 100Hz when setting them up, but two don't really have the SD or Xmax to give a decent volume level at 50Hz let alone one.

One is fine in my center to 100Hz or even 80, but the extra excursion demands from then on are too much, I think.

Steve

 

[planet10]

What is the formula to calculate the diameter of the tube I would have to use ?

The Q on these is a low for doing a straigh el pipe-o (these work best if 0.5<Q<1.0). For low Q drivers a ML-TL (mass-loased TL ie restricted port) is probably the ticket. This could be done in an el pipe-o style but you would need a restrictor plate at the top.

To figure out the detail you would need to some modeling in Martin King's TL SW

dave

 

[planet10]

The tube diameter is related to the parameter Sd of your driver. Normally if you have a 10'' driver, you use a 10'' tube.

Actually the tube diameter is only indirectly related to Sd -- it is actually related to Vas (which tends to get bigger with bigger drivers). If you want to use Sd you can get a reaonable ballpark by using a tube of x-section area of 3 Sd. Sd is far to restrictive for almost any driver and you won't get anywhere near the driver's potential.

dave

 

[kanaddict]

The Q on these is a low for doing a straigh el pipe-o (these work best if 0.5<Q<1.0). For low Q drivers a ML-TL (mass-loased TL ie restricted port) is probably the ticket. This could be done in an el pipe-o style but you would need a restrictor plate at the top.

To figure out the detail you would need to some modeling in Martin King's TL SW

dave

Thanks Dave !

Do you think that a ML-TL would sound better then a regular ported box ? Do they provide the same benefit as TL design ?
On my B&W P4, the exit of the TL is about 2" H x 5" w, is it a ML-TL ?

I'll read all I will find on your web site (Jonh R. writing sound good) and other site related to TL.

I will probably ask more question within the next weeks !

Stay tuned !

Actually the tube diameter is only indirectly related to Sd -- it is actually related to Vas (which tends to get bigger with bigger drivers). If you want to use Sd you can get a reaonable ballpark by using a tube of x-section area of 3 Sd. Sd is far to restrictive for almost any driver and you won't get anywhere near the driver's potential.
dave

I want to use the drivers full potential and if I have to do ported boxes for this, then I'll do it. But.....if the ML-TL can get me a more natural Bass, then I'll take that road. These bass speakers will be use for music only, no HT 😉

Regards,

 

[planet10]

Do you think that a ML-TL would sound better then a regular ported box ? Do they provide the same benefit as TL design ?

I'm not a big fan of ported boxes. My BD-Pipes with are ML-TQWTs were a relevation to me.

An ML-X looks similar to a bass reflex except that one dimension is long to support a 1/4 wave resonance, and the restricted port acts as a low-pass filter. FEA shows that the behaviour of an ML-x is significantly different than a ported box of the same volume and port size. They do give you the benefits of a TL.

How tall are your B&Ws?

dave

 

[kanaddict]

How tall are your B&Ws?

dave

Thanks for the information about the ML-TL ! I'll download the MATHCAD software and try to figure out how it work

The B&W P4 are 32.5" tall. They are little floor standing speaker. When I bough them in 1998 they were the best in their price range. The bass of the P4 sound a lot better then many actual speakers made by B&W.

I scanned some documents for you :

http://photos.yahoo.com/bc/daniel_si50mkii/lst?.dir=/BW+P4&.view=t

Best regards,

 

[FrankDIY]

B&W are great speakers. I like them.

 

[planet10]

Thanks for the information about the ML-TL ! I'll download the MATHCAD software and try to figure out how it work

Make sure you read thru the Focal TL and ML-TQWT articles as they are as close to instruction manuals as you can get. Also a read thru Bob Brines site.

I scanned some documents for you

A little hard to read at that size, but the pic clearly shows a heavily tapered TL, with a slightly restricted port.

These never showed up at my B&W dealer here in Canada. Too bad. I do like my DM302s thou.

dave

 

[kanaddict]

Make sure you read thru the Focal TL and ML-TQWT articles as they are as close to instruction manuals as you can get.

Could you tell me where I can find these articles ?

I just read that speakers with a big Vas should be avoid for TL.
The Focal I have are 10" and have a Vas of a bigger woofer. So, that make me wonder if I follow the good road

Also a read thru Bob Brines site.

OK, I'll try to find this site

A little hard to read at that size, but the pic clearly shows a heavily tapered TL, with a slightly restricted port.
These never showed up at my B&W dealer here in Canada. Too bad. I do like my DM302s thou.
dave

They were retired in 1998. I got the last "new in the box" pair my dealer had. If you like TL, I'm sure that you would had prefer them to the DM302

I want to build speaker that will be better then the P4 and it's a good chalenge in many way 😉

Regards,

 

[planet10]

Could you tell me where I can find these articles ?

My site: URL in the sig

Martin King's Site

Bob Brines Site

dave

 

[kanaddict]

Dave,

thanks a lot !

I'll now read & read again all these articles. I'll ask questions when needed.

Carry on ! (I'm a Kansas fan 😉 )