Highish Q FR speaker in BLH enclosure?

[Mosquito]

Hi,
For sentimental reasons, and just for fun, I want to use a pair of ancient full range drivers, that someone give me for very little money...
I haven't yet measured these, but I suspect this 8 " inchers to have a 60/70 Hz free air resonance and Qts around 0.8 / 1.0.
Will be possible to mount them in a BLH type enclosure, in order of avoid the use of any baffle step correction circuit ?
I prefer an efficient thing, to be driven by a very low wattage tube amp, so, I'm prepared to sacrifice the low end response (< 50Hz)...
Thanks for any input

 

[Chaz H]

According to an MJK article I read, the higher the driver Qts, the more bass output from a BLH (in terms of volume, not depth). The output will certainly compensate for baffle step, but .8-1 might be a little boomy; the ideal range seemed to be around .6-.7.

 

[CLS]

Why not make some simulations yourself?

Hornresp

 

[GM]

According to an MJK article I read, the higher the driver Qts, the more bass output from a BLH (in terms of volume, not depth). The output will certainly compensate for baffle step, but .8-1 might be a little boomy; the ideal range seemed to be around .6-.7.

Absolutely! Reverse engineer one of these essentially open back FLHs and you'll be surprised at how high the driver's effective Qts is to achieve this plus get a 1:1 CR to maximize efficiency with a ~transient perfect response: http://www.audioheritage.org/images/lmco/photos/products/shearer/shearer1.jpg

Right, such systems as this can't be used wide range due to its high gain without horn loading the front of the driver too, so increasing the BLH's filter chamber from the ideal and starting with a smaller than ideal throat to 'shrink' the horn, hence its gain, is required.

Basically, you wind up with what I call a big vent reflex [BVR] since its actual horn [as opposed to TL] loading is limited to a narrow BW above ~ 70-80 Hz.

GM

 

[Mosquito]

Ok, thanks, once I get the units effectively measured, I'll decide for some kind of BLH or a BVR type.
CLS , I don't have a clue on how this software works, there is a step -by - step worked example somewhere?
Anyway you guys already answered my question: "...in order of avoid the use of any baffle step correction circuit ?" and the answer is "yes"
Thanks again

 

[freddi]

if the mids and highs are strong enough then they would probably "work" in a 12" Karlson enclosure.

 

[Mosquito]

Hi Freddi, this idea crossed my mind, but the complexity exceeds my woodworking skills...

 

[freddi]

Karlson = probably easier than some blh. Wings can be radial arc drawn with a stick-compass and cut with a jigsaw. Two internal baffles: the speaker baffle and the port panel. Use cleats, screws and glue to hold the baffles in proper position. A rear shelf can be added as a lowpass filter in conjunction with a bonded dacron or fiberglass pad. One 4 foot by 8 foot sheet of plywood or particleboard could yield both enclosures.

 

[Mosquito]

Ok, I think I got somewhere in my notebook the K-12 plans, and I'm aware that this box likes to some particular 8" drivers.. let me think about it... mmmm
In the neighbourhood there is a home depot-like store, that I believe, carries 16mm and 20 mm plywood, will see..

 

[Mosquito]

I must confess that my first thought was something ultra-simple, like this one:
Do it yourself Voigt Hifi horn loudspeakers!
Yeah , I'm lazy...