Greets!
Absolutely! The original Bell Labs/W.E. 50-10 kHz horn had a ~15.6 ft pathlength IIRC and when soundtracks were developed with a wider BW, they found that supplementing it with a simple baffle mounted dipole woofer on the low end and a super tweeter on the high end 'echoed' horribly, to the detriment of speech intelligibility. There were also huge problems with off axis response due to the radically different polar responses.
This is why W.E. et al, switched to dual and quad driver LF/midbass horns and separate sectoral or multicell mids/HF horns, first with 'W' fold basshorn designs that only partially solved the problem, and finally with truncated straight reflex loaded midbass horns once more powerful amps became available to boost the low end.
With the advent of multi-channel concerts and movies, B*** developed driver arrays that quite frankly 'blew away' the horn 'status quo' in both venues, but their pricing was prohibitive so few systems were sold AFAIK. While HI-FI line arrays have some benefits, they don't 'translate' as well in a small space as they do in a space large enough to be considered a point source, except down low with a low XO point, and why a manifold IB loaded with multiple low Qts drivers is a viable, and maybe even better, choice overall since it will go lower in a high SAF configuration, with the trade-off of course being more expensive.
GM
Absolutely! The original Bell Labs/W.E. 50-10 kHz horn had a ~15.6 ft pathlength IIRC and when soundtracks were developed with a wider BW, they found that supplementing it with a simple baffle mounted dipole woofer on the low end and a super tweeter on the high end 'echoed' horribly, to the detriment of speech intelligibility. There were also huge problems with off axis response due to the radically different polar responses.
This is why W.E. et al, switched to dual and quad driver LF/midbass horns and separate sectoral or multicell mids/HF horns, first with 'W' fold basshorn designs that only partially solved the problem, and finally with truncated straight reflex loaded midbass horns once more powerful amps became available to boost the low end.
With the advent of multi-channel concerts and movies, B*** developed driver arrays that quite frankly 'blew away' the horn 'status quo' in both venues, but their pricing was prohibitive so few systems were sold AFAIK. While HI-FI line arrays have some benefits, they don't 'translate' as well in a small space as they do in a space large enough to be considered a point source, except down low with a low XO point, and why a manifold IB loaded with multiple low Qts drivers is a viable, and maybe even better, choice overall since it will go lower in a high SAF configuration, with the trade-off of course being more expensive.
GM
Hi rick,
I'm hoping for 20Hz to 150Hz with flare cut off at about 15Hz.
Initially I'll use DCX2496 to set up the crossovers, with and without delay on the upper drivers.
Then use these numbers to generate a discrete opamp based set of active crossover filters.
150Hz might demand too strong a motor from the sub driver/s and/or crossover/delay anomalies may tempt me to change to somewhere closer to 100Hz. Very much an experiment. My main stereo speakers go down to about 40Hz and the 5.1 speakers down to about 50Hz so a fair amount of leeway (1 to 1.8 octaves) for crossing over lower.
I do not want big powerfull vented boxes or IBs for the bottom end. I was hoping for single driver mono horn, but seems that multi driver has some advantages. Pity about the expense and potential waste (power and electronics).
I'm hoping for 20Hz to 150Hz with flare cut off at about 15Hz.
Initially I'll use DCX2496 to set up the crossovers, with and without delay on the upper drivers.
Then use these numbers to generate a discrete opamp based set of active crossover filters.
150Hz might demand too strong a motor from the sub driver/s and/or crossover/delay anomalies may tempt me to change to somewhere closer to 100Hz. Very much an experiment. My main stereo speakers go down to about 40Hz and the 5.1 speakers down to about 50Hz so a fair amount of leeway (1 to 1.8 octaves) for crossing over lower.
I do not want big powerfull vented boxes or IBs for the bottom end. I was hoping for single driver mono horn, but seems that multi driver has some advantages. Pity about the expense and potential waste (power and electronics).
Hi Andrew
> hoping for 20Hz to 150Hz with flare cut off at about 15Hz
> the flare doubles in area each 1.4m along the centre line.
I’m only looking at a 50 to 200 Hz, with JBL 2202Hs.
Using (in Volvotreter’s Tractrix spreadsheet) the Midbass Fronthorns sheet for hyperbolic exponential horns, placement factor est @ 6.5, I need a mouth 1.0 *0.57 m (39 * 22”); and it’s 2.25 m (89”) long.
What are you modelling with, and how long would a 15 Hz be?
> 150Hz might demand too strong
What’s the Fmh?
Cheers
> hoping for 20Hz to 150Hz with flare cut off at about 15Hz
> the flare doubles in area each 1.4m along the centre line.
I’m only looking at a 50 to 200 Hz, with JBL 2202Hs.
Using (in Volvotreter’s Tractrix spreadsheet) the Midbass Fronthorns sheet for hyperbolic exponential horns, placement factor est @ 6.5, I need a mouth 1.0 *0.57 m (39 * 22”); and it’s 2.25 m (89”) long.
What are you modelling with, and how long would a 15 Hz be?
> 150Hz might demand too strong
What’s the Fmh?
Cheers
Hi Rick,
I have started using hornresponse but I cannot get rid of the ripples unless I select an infinite horn.
Most of my design is based on formulae that I found on the web.
A single driver (15inch) and throat = 400sqcm giving a compression (Sd/Tharea) of about 2, mouth = 3.6sqm gives a length of about 8m+, much >20Hzwavelength/4. That's why I can afford to chop the throat end. But a bigger decision yet to be made is whether to load the rear. They will be enormous box/es if needed and I would rather avoid the space, effort and resources.
Mouth is corner loaded for 8times area. My hope is that the resistive load due to adequate length and effective mouth should not require back loading to correct the response in band.
I have started using hornresponse but I cannot get rid of the ripples unless I select an infinite horn.
Most of my design is based on formulae that I found on the web.
A single driver (15inch) and throat = 400sqcm giving a compression (Sd/Tharea) of about 2, mouth = 3.6sqm gives a length of about 8m+, much >20Hzwavelength/4. That's why I can afford to chop the throat end. But a bigger decision yet to be made is whether to load the rear. They will be enormous box/es if needed and I would rather avoid the space, effort and resources.
Mouth is corner loaded for 8times area. My hope is that the resistive load due to adequate length and effective mouth should not require back loading to correct the response in band.
AndrewT said:
Greets!
There's a number of suitable drivers available, with the late, great Altec 515-8G probably being the best known and available new under the Iconic brand. Then there's JBL's low Vas variant, the 2226H and the various brand's clones of these, so plenty to choose from.
The delay will be impossible to correct enough AFAIK, so a better solution IMO would be a BLH with a flare frequency = Flm, which will dictate a hyperbolic flare rate, then terminate it at whatever frequency best blends with the room's gain curve. Note that using the entire corner from floor to ceiling as the mouth is best since it will reduce reflections back to the throat (passband 'ripple') due to it acoustically appearing to be an infinite mouth.
GM
catapult said:
Greets!
Thanks for the update! I knew I was somewhat behind the times WRT electronics, but not this far.
The Rane, dbx, etc., units I'm familiar with are limited to a few ms. In doing a quick search, I see the BSS OmniDrive has a staggering 2.6 sec of delay available (~895.5 m), but the trade-off is an 11 ms minimum adjustment step (~3.79 m), so not practical for a typical HI-FI app. Regardless, for typical HI-FI apps, the BLH is IMO a better solution when this low/wide a BW is desired.
As always though, YMMV.
GM
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