Definitely not !
A frequency multiplied by 1.5 gives a perfect fifth (Quinte in German). The interval between our new tone and the next octave would be a perfect fourth (Quarte).
Regards
Charles
A frequency multiplied by 1.5 gives a perfect fifth (Quinte in German). The interval between our new tone and the next octave would be a perfect fourth (Quarte).
Regards
Charles
So when we have for example 1kHz as "source", the third harmonic will be 3 kHz.
To go down an octave from 3 kHz will get us to 1k5.
So we need another 500 Hz to get back to our source frequency.
500 Hz is one sixth of 3kHz.
Agreed Charles yours is the musical approach.
I was calculating in Herz after having my morning coffee 😉
Squirrel,
thanks Pano, it would have been interesting to see what you came up with for that combination. If it wasn't for leaving those speakers original I'd coat the back side of the horn with a damping material and perhaps put some foam inside the mouth. Those aluminum castings do ring a bit untreated.
thanks Pano, it would have been interesting to see what you came up with for that combination. If it wasn't for leaving those speakers original I'd coat the back side of the horn with a damping material and perhaps put some foam inside the mouth. Those aluminum castings do ring a bit untreated.
Truck bed liner works well on baffles. You can get it in a spray can at NAPA. I used a 3M spray on sound deadener for my turntable platter. Worked great.
3M Sound Deadener
As for the crossover, I probably settled on 2nd order Bessel circa 900Hz with a shelf filter boost over about 3K. I also used 3rd order high pass near the same frequency and found it works well, probably because it became 4th order acoustic. The shelf is mandatory.
3M Sound Deadener
As for the crossover, I probably settled on 2nd order Bessel circa 900Hz with a shelf filter boost over about 3K. I also used 3rd order high pass near the same frequency and found it works well, probably because it became 4th order acoustic. The shelf is mandatory.
yes, but isn't the SPL diminished (attenuated) 1.5 octaves higher from the fundamental?
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Or, like some people says, "you cannot correct time with amplitude"!
In some if not most cases, the corrected driver will continue to ring/act bad at "corrected" frequency, only a little less perceptible due to "normalized"/corrected amplitude. Better is to use better driver IMHO
Thanks Pano. I don't want to spray anything on the horn, collectors would not like that but I like your xo ideas.
Nuconz,
The point I think we are trying to make is that a device that has a real mechanical resonant problem really can't be corrected by electrical means. You may be able to attenuate it by using multiple notch filters but why should you have to cut holes in the program material to do that. The resonance will still show up in a waterfall plot as a hanging frequency in time.
Nuconz,
The point I think we are trying to make is that a device that has a real mechanical resonant problem really can't be corrected by electrical means. You may be able to attenuate it by using multiple notch filters but why should you have to cut holes in the program material to do that. The resonance will still show up in a waterfall plot as a hanging frequency in time.
Collectors? I had to GIVE away my 811 horns. 🙁 If they are like new, then they may fetch a little money.
Get them bolted down tight to the baffle and that will help a lot. Wrap an Ace bandage or two around the throat, that will kill ringing there. Hard to do perfectly removable damping. Wrap them in cling wrap, put them in a box and fill the box with sand?
Get them bolted down tight to the baffle and that will help a lot. Wrap an Ace bandage or two around the throat, that will kill ringing there. Hard to do perfectly removable damping. Wrap them in cling wrap, put them in a box and fill the box with sand?
Pano,
The Barcelona cabinets are so different than most of the Altec industrial designed versions of the A7. The wood is real Walnut and the grills are nicely molded urethane I think and look like wood with the cloth backing. I do believe that there are collectors for these types of older equipment that doesn't look like it belongs behind a movie screen where you can't see it. Sort of like the collectors of older McIntosh tube gear, I sold mine years ago for some nice change, they were damned ugly industrial grey finished.
The Barcelona cabinets are so different than most of the Altec industrial designed versions of the A7. The wood is real Walnut and the grills are nicely molded urethane I think and look like wood with the cloth backing. I do believe that there are collectors for these types of older equipment that doesn't look like it belongs behind a movie screen where you can't see it. Sort of like the collectors of older McIntosh tube gear, I sold mine years ago for some nice change, they were damned ugly industrial grey finished.
Oh, sorry. Yeah. If they are part of a nice cabinet then OK. I don't think spraying the out of sight parts would hurt the value, but I'm not a collector!
Kindhornman,
I do know those Barcelona cabinets, my next door neighbor had a set of those.
GM said they had the Altec 411 woofers. Do yours have the original woofers?
I tried to get them for my workshop when my neighbor decided to sell them. But they ended up being a bit too pricy (for a garage) and the surrounds (which had been fixed before) were completely shot. He used them in home coupled with a modern surround system and subs 😱. I really liked the look of the cabinetry. his horns were treated though. Sadly I haven't heard any variant of the A7 yet.
They sure don't look like Altec's, they look more like something JBL would have done back in the day of large console systems.
Altec Barcelona - Google Search
Wesayso, yes they still have the original air suspension 411 woofers, never been touched, surrounds are still perfect. I think since they have never been exposed to any sunlight and have been covered all these years they have survived without the foam falling apart. I do understand what people are saying about foam surrounds, it is a shame really as all it took was some UV additive to take care of that problem. JBL had that problem with some of their molded eggcrate grills on many home models, they just crumbled.
Altec Barcelona - Google Search
Wesayso, yes they still have the original air suspension 411 woofers, never been touched, surrounds are still perfect. I think since they have never been exposed to any sunlight and have been covered all these years they have survived without the foam falling apart. I do understand what people are saying about foam surrounds, it is a shame really as all it took was some UV additive to take care of that problem. JBL had that problem with some of their molded eggcrate grills on many home models, they just crumbled.
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