BSC question

[Klimon]

Hi folks,

I just purchased a pair of Tangband W5-1611 to fit into existing TL cabinets that used drivers with similar T/S parameters. There's a kit with the TB's called Flat 5, a ~40cm (1,3feet) wide BR or TL (two versions IIRC) that claims, as do many of it's owners, it doesn't need BSC by virtue of it's wide baffle.

I'ld prefer not to use BSC either, so will add a frugelhorn-style suprabaffle on my cabinets, BUT: using trueaudio's formula, a 40cm baffle translates into 285Hz baffle step f3.....

How is it that the ~2 remaining octaves that still are -3db cause no annoyment, or is this countered by room interaction?

Muchos gracias compadres,

Simon

[ScottG]

Originally posted by Klimon
Hi folks,

I just purchased a pair of Tangband W5-1611 to fit into existing TL cabinets that used drivers with similar T/S parameters. There's a kit with the TB's called Flat 5, a ~40cm (1,3feet) wide BR or TL (two versions IIRC) that claims, as do many of it's owners, it doesn't need BSC by virtue of it's wide baffle.

I'ld prefer not to use BSC either, so will add a frugelhorn-style suprabaffle on my cabinets, BUT: using trueaudio's formula, a 40cm baffle translates into 285Hz baffle step f3.....

How is it that the ~2 remaining octaves that still are -3db cause no annoyment, or is this countered by room interaction?

Muchos gracias compadres,

Simon

The problem here is we won't know how the driver + T-line will effect the response in the baffle step region.

If you knew that then you could just sum it with modeling on the Edge and the Room Response Calculator.

http://www.tolvan.com/edge/help.htm

http://www.pvconsultants.com/audio/reflection/rrc.htm

[Klimon]

Thanks for the links Scott. I forgot about the edge but playing with it already revealed me some info; I'll probably settle on a 50cm suprabaffle. BS drops from f0 to f3 between 200 and 100hz.... I think there'll always remain a gap between TL output and BS drop but as such it seems acceptable.

Listening area is too changing now to simulate room interaction so I'll prep the cab and hear what it gives.

Cheers ,

Simon

[ScottG]

Originally posted by Klimon


Listening area is too changing now to simulate room interaction so I'll prep the cab and hear what it gives.

Cheers ,

Simon

True, but at some level there will be room-gain. In other words cut-out the boundary and modal (gains and losses), and you'll be left with some room gain.

Martin Colloms generated a generic room-gain curve that basically stated that you'll have +2 db for every halving of Hz starting at 200 Hz. (i.e. from the average 200 Hz near 0 gain, 100 Hz +2db, 50 Hz +4db, 25 Hz +6db..) It certainly isn't accurate - but it's something to work with.

[Klimon]

Martin Colloms generated a generic room-gain curve that basically stated that you'll have +2 db for every halving of Hz starting at 200 Hz. (i.e. from the average 200 Hz near 0 gain, 100 Hz +2db, 50 Hz +4db, 25 Hz +6db..) It certainly isn't accurate - but it's something to work with.

Very interesting, that would almost exactly (keeping in mind the simulatory and rule of thumb character of the data) counter the BS in the case in question. This could also explain why with the Flat 5 people don't complain about a low-midbass hole.

Regards,

Simon