I've seen several designs like this. What is the advantage or disadvantage of having no compression chamber (neither front nor rear)? I've only seen it this way on big horns. Can the same approach be beneficial on smaller bass horns, since it obviously makes construction much easier, just build a horn and fire the driver directly into the throat? Are there situations or driver specs that make it the optimum route?
Compression chambers vs free air:
A front compression chamber is not linear. At low sound levels it seems like the sound will not come out of the horn, at a certain sound level the sound is really good (before compression occurs) and at high sound levels the sound will be compressed.
The compression is why you often cannot hear a deep note on the bass guitar simultaneous as a kick drum. The attack of both instruments transforms into a common compressed mud bath without transients.
David Lee of Bassmaxx gave me a good description of disadvantages of rear compression chambers. At low sound levels the cone movement is linear with a rear compression chamber. At higher levels the spring effect of the air in the chamber damps the cone movement more and more as the sound pressure differences in the chamber grows. Let us try one example: when you give your driver 2,83Volts, the cone movement should have been 0,5mm @ 40Hz, and this is also what you can measure. When you give your driver 28,3Volts @ 40Hz the cone movement should have been 5,0mm and when you measure it you get only 3,6mm because of the spring effect in the chamber.
A front compression chamber on a basshorn can work as a lens when you move your crossover point up in the mids where the diameter of the cone is large compared to the wavelength around the crossover frequency (like in the Altec A7 system). This can help a designer to have a more similar polar pattern in the crossover region (beaming will occur on a higher frequency).
A rear compression chamber will make the driver work as if it where in a closed box at frequencies with wavelengths larger than four times the length of the horn. You get extended bandwith and protection.
If you try to drop the rear compression chamber on a short horn, you will processing or at least a hp filter to protect the driver from large excursions.
The most important factor of choosing to drop compression chambers would be linear sound at all levels (if designed right of course
The drawback with an open design is more impact because one side of the cone does not have any damping except for free air. Then the ultimate solution would be to build two similar horns and load each side of the cone with one of them, and of course you'll need a bigger house.....hehe
My ears like the sound of open back horn designs much better than traditional horns containing compression chambers, but you will have to check it out yourself to find your own preference
Driver specs for open back design:
Same as for traditional horns pluss you can use drivers with higher QTS and lower Bl and of course high excursion drivers.
A front compression chamber is not linear. At low sound levels it seems like the sound will not come out of the horn, at a certain sound level the sound is really good (before compression occurs) and at high sound levels the sound will be compressed.
The compression is why you often cannot hear a deep note on the bass guitar simultaneous as a kick drum. The attack of both instruments transforms into a common compressed mud bath without transients.
David Lee of Bassmaxx gave me a good description of disadvantages of rear compression chambers. At low sound levels the cone movement is linear with a rear compression chamber. At higher levels the spring effect of the air in the chamber damps the cone movement more and more as the sound pressure differences in the chamber grows. Let us try one example: when you give your driver 2,83Volts, the cone movement should have been 0,5mm @ 40Hz, and this is also what you can measure. When you give your driver 28,3Volts @ 40Hz the cone movement should have been 5,0mm and when you measure it you get only 3,6mm because of the spring effect in the chamber.
A front compression chamber on a basshorn can work as a lens when you move your crossover point up in the mids where the diameter of the cone is large compared to the wavelength around the crossover frequency (like in the Altec A7 system). This can help a designer to have a more similar polar pattern in the crossover region (beaming will occur on a higher frequency).
A rear compression chamber will make the driver work as if it where in a closed box at frequencies with wavelengths larger than four times the length of the horn. You get extended bandwith and protection.
If you try to drop the rear compression chamber on a short horn, you will processing or at least a hp filter to protect the driver from large excursions.
The most important factor of choosing to drop compression chambers would be linear sound at all levels (if designed right of course
The drawback with an open design is more impact because one side of the cone does not have any damping except for free air. Then the ultimate solution would be to build two similar horns and load each side of the cone with one of them, and of course you'll need a bigger house.....hehe
My ears like the sound of open back horn designs much better than traditional horns containing compression chambers, but you will have to check it out yourself to find your own preference
Driver specs for open back design:
Same as for traditional horns pluss you can use drivers with higher QTS and lower Bl and of course high excursion drivers.
It depends on the SPL levels you need.
If you need realistic concert levels a two ways system should be concidered.
Example: Frontloaded horn for the "fullrange" driver and a sideloaded horn for the bass driver. Crossover below 150 Hz.
I have tried a frontloaded horn with a 4" fullrange driver and a Waves Maxxbass processor with excellent results. The horn had frequency responce down to 80 Hz and the processor made it go down to 50 without problems
The Maxxbass processor is a diamond that for most people seems undiscovered. Try it out if you have the chance.
When I have tried the fullrange 4" driver in larger front loaded horns I have got problems with the high frequencies (beaming) because of the "large" diameter of the driver. Maybe that could be better with a compression chamber, but then low frequencies would make distortion and compression of the sound.
Both calculations and real life also shows that high freguencies will be decreased in many large horn designs....hmmmmm this is difficult.
If you need realistic concert levels a two ways system should be concidered.
Example: Frontloaded horn for the "fullrange" driver and a sideloaded horn for the bass driver. Crossover below 150 Hz.
I have tried a frontloaded horn with a 4" fullrange driver and a Waves Maxxbass processor with excellent results. The horn had frequency responce down to 80 Hz and the processor made it go down to 50 without problems
The Maxxbass processor is a diamond that for most people seems undiscovered. Try it out if you have the chance.
When I have tried the fullrange 4" driver in larger front loaded horns I have got problems with the high frequencies (beaming) because of the "large" diameter of the driver. Maybe that could be better with a compression chamber, but then low frequencies would make distortion and compression of the sound.
Both calculations and real life also shows that high freguencies will be decreased in many large horn designs....hmmmmm this is difficult.
Skramstad,
Thanks again, but I was talking about a rear loaded horn, so efficiency in the horn isn't the goal, since I'd want that to match the front output above the horn cutoff.
Also, thanks for the feedback about BassMaxx. Maybe that's the way to go to extent bass on a full ranger without going with rear horn loading. Also, I need to try BassMaxx with my dipoles and get the extra extension for free. Of course nothing beats the physical impact of the real fundamental, even if you trick your ears into hearing it.
Thanks again, but I was talking about a rear loaded horn, so efficiency in the horn isn't the goal, since I'd want that to match the front output above the horn cutoff.
Also, thanks for the feedback about BassMaxx. Maybe that's the way to go to extent bass on a full ranger without going with rear horn loading. Also, I need to try BassMaxx with my dipoles and get the extra extension for free. Of course nothing beats the physical impact of the real fundamental, even if you trick your ears into hearing it.
Oh, I see.
Would not recommend rear loaded horn.
There will always be a bandpass of ugly stuff in the region where the horn takes over.
If your horn is long, you'll also get the car effect where you get the attack of the bass sounds first, and a little bit later you get the thunder....
Just have to clear up some confusion:
Bassmaxx = horn subwoofers with open back design
Maxxbass = processor from Waves in rackformat (really worth trying)
The physical impact of the real fundamental would always be the best (Good point you got there, really liked it!)
Would not recommend rear loaded horn.
There will always be a bandpass of ugly stuff in the region where the horn takes over.
If your horn is long, you'll also get the car effect where you get the attack of the bass sounds first, and a little bit later you get the thunder....
Just have to clear up some confusion:
Bassmaxx = horn subwoofers with open back design
Maxxbass = processor from Waves in rackformat (really worth trying)
The physical impact of the real fundamental would always be the best
(Good point you got there, really liked it!)Skramstad,
It sounds like you've used the MaxxBass hardware. Have you used the software. I think that's the route I'm more interested in. With the software version I'll avoid putting extra electronics in the signal path. Plus I won't need 3 pieces of hardware. I'll just convert recordings for main system use, car use, and office use to match each set of speakers. Also, the software version uses the improved version of the MaxxBass algorythm. Any thoughts?
It sounds like you've used the MaxxBass hardware. Have you used the software. I think that's the route I'm more interested in. With the software version I'll avoid putting extra electronics in the signal path. Plus I won't need 3 pieces of hardware. I'll just convert recordings for main system use, car use, and office use to match each set of speakers. Also, the software version uses the improved version of the MaxxBass algorythm. Any thoughts?
two sources more than a wavelength apart will start doing funny
polar patterns
Just,in this case its many metres rather than 30cm distance for a midrange
The horn mouth has to be quite large to load the bass and keep it directive-the mouth has to be >1 CIR - so the mouth circumference must be SEVERAL times larger than the lowest frequency to be 'directive' .
Just imagine an HF horn but scale it up in size
the owner of the 6080 horn could measure it I guess,roughly
ultrasonic weapons could probably be made using a horn which could make a beam of ultra intense sound in the ultra high frequencys.
On the isue of simultanuis front and backloaded horns
What if there were no distance between the two horn mouths? what I mean is if you folded the horns so that the mouths were placed very close together, but facing opposite directions. As the distance gets smaller it might become more dipolar
On the isue of simultanuis front and backloaded horns
What if there were no distance between the two horn mouths? what I mean is if you folded the horns so that the mouths were placed very close together, but facing opposite directions. As the distance gets smaller it might become more dipolar
Sonic weapons use destructive ultra low frequencies. If I remember correctly 7hz is the bad one. The best idea I've seen for using sound as a weapon (other than for psychological use) is to use 2 high output sound sources of higher harmless frequencies directed at the target from 2 directions so that at that point the 2 sets of waves combine to create a destructive tone only in the target location.
I read somewhere that 5 - 7 Hertz is the resonant frequency of the Earth.
Seems to me that there is a big problem with using ultra-low frequency bass cannons as a weapon. The omni-directional infrasonic sound would propigate back on those individuals attempting to use the weapon, redering them as helpless as the intended victims of the sonic device.
So, what would be the point of incapaciting every soldier on the battlefield regardless of which army they belong are in? Hummmmmm.
Larry
Seems to me that there is a big problem with using ultra-low frequency bass cannons as a weapon. The omni-directional infrasonic sound would propigate back on those individuals attempting to use the weapon, redering them as helpless as the intended victims of the sonic device.
So, what would be the point of incapaciting every soldier on the battlefield regardless of which army they belong are in? Hummmmmm.
Larry
I recall reading that the military implementation of infrasound utilized two high-frequency drivers a certain distance apart driven with very slighly differing frequency sine waves to create infrasonic beats. This method is very directional, due to both the directionality of the high frequencies and the narrow line perpendicular to the two sources where the interference patterns occured.
Edit: Oops... this is what johninCR said, isn't it!
Edit: Oops... this is what johninCR said, isn't it!
Lsharptec1 said:
I read a story (one of those internet things that may be fiction but is plausible enough that it could be true) about a French scientist who experimented with LF for use as a weapon decades ago and one or more of his assistants died trying to turn the thing off because they hadn't properly considered the omnidirectional nature of the sound waves they were creating.
sonic weapons here!
http://www.borderlands.com/archives/arch/gavreaus.htm
who's building one of these then?
gazza
http://www.borderlands.com/archives/arch/gavreaus.htm
who's building one of these then?
gazza
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