| Romy the Cat wrote:|
| Make an experiment, and I will simplify the case quite assertively. Take a typical compression driver, cross it at 800Hz, second order and load it into a proper contemporary horn (Tratrix or JMLC) of 300Hz. Listen that horn, you will get some sort of sound that let accept as OK Sound. Now begin to very slow lower the crossover point and keep listening the channel. While you lowering the crossover point, somewhere around 550Hz (I took this number purely arbitrarily as it would depends from VERY MANY circumstances) the horn will begin to demonstrate what I call “choked sound”. The “choked sound” is HOW HORNS SOUND IN 99% OF ALL HORN INSTALLATIONS OUT THERE – people just too damn to deal with it. The “choked sound” is the satiation when Sound produced by a driver can’t be “processed” by horn. In this “choked mode” a horn produces the “sonic boom” that was made by the horn’s bell and that “sonic boom” screw up the enter band-pass of the channel - the game is over. Increasing of the crossover point for ¼ octave (for instance) will fix the situation - so we have approximately one octave between horn’s rate and mix crossover point…|
| Romy the Cat wrote:|
| The Upper Bass 115Hz Tractrix. That is another candidate to employ the Exponential “thump” but let look deeper. In the Jessie’s case the Upper Bass will be the only properly implemented Upper Bass that I ever seen. No one, including me, can afford to have 115Hz Tractrix and to cross it at 240Hz. All our horns are fundamentally compromised because we are trying to push more bass out of our horn running them the last “octave down”. Jessie has no need to push the “last drop” from his Upper Bass horn as he has his Mid Bass horns. |
Well, I was dreaming to play with it for years and now it is the reality. With the new 6-channel Super Milq the Macondo’s UpperBass is driven with own amp with over 14 attenuation, that means that I might use in the UpperBass channel any driver I wish – I have power and gain to drive it.
My UpperBass horn is John Hasqiun made, glued SDF, heavy, 4” into 35”, fully Tratrix, tunes for 115Hz, floor-sitting, “Macroimbedded” in the room, pushing at listening spot ~95Hz-100Hz at 109dB sensitivity. It crossed from 70Hz to 500Hz – first order of course. It uses 103dB sensitive Fane Studio 8M (paper- clothe, long external spider), used as a compression driver. Years ago when I researched the subject of the drivers for my UpperBass horns and when I was trying many alternatives I was restricted by sensitivity (6db was coming from horn and I was targeting for 109dB). Now I do not restricted by sensitivity. The channel does very-very nice, without exercising the unnecessary humbleness I would testify that it does better then any other front-loaded upperbass I have heard. Still, it is not the perfect upperbass as I feel that I cross it too low. I do not want to rise the crossover point at my woofers towers – which is 65Hz and I have no midbass horn.
So, I slowly begin to think what kind drivers, loading methods, of anything else I might use it order to tune off the crossover proximity effect in the direction I envision. My primary route of exploration, as I see it now, will be going away from the compression driver topology as I feel it is not right direction for bas. I feel that the bass cones should not be dumped too much as it takes place in a compression drivers. Perhaps a different dumping model, or perhaps some help from amp’s output impedance, of perhaps to drive a driver with an idle plate might do the trick - will see… I very much open to try other drivers as well – anything from 4” to 10”… as long they will handle my TTH demands.
In future when I finish the Second Super Melquiades and will set my playback up as it should be I will be slowly experimenting with my Upper Bass drivers… If you have any interesting ideas on your radars then feel free to dump them in this thread. I will slowly update the thread with my progress…Rgs, Romy the Cat
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche