tagger Posted March 21, 2012 Share Posted March 21, 2012 Anyone have a clever way to mount a tweeter horn on top of an Altec multi-cellular horn without building a motorboard? Quote Link to comment Share on other sites More sharing options...
juniper8 Posted March 21, 2012 Share Posted March 21, 2012 How about a wedge and some heavy duty velcro? It might make it easier if you post some pictures. I have used this type of velcro, and it has substantial holding power. Quote Link to comment Share on other sites More sharing options...
tagger Posted March 21, 2012 Author Share Posted March 21, 2012 I'm using 1003b's but I think all the Altec multi-cells have a similar concave top slope. If it helps I can post a photo tonight. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 21, 2012 Share Posted March 21, 2012 if the tweeter is small enough put it inside the horn as in this example with a k-5-j Quote Link to comment Share on other sites More sharing options...
tagger Posted March 21, 2012 Author Share Posted March 21, 2012 if the tweeter is small enough put it inside the horn as in this example with a k-5-j That was my first instinct, which would also get them much closer to co-axial, but the tweeter I'm using (APT-50 with either the baby cheeks horn or a small Dayton waveguide horn - I have both) would almost completely block the horn cell it's mounted within. And the middle cell it would occupy fires right towards the listening sweet spot. I'm afraid that would negatively alter the response when listening on-axis. For those that aren't familiar with the Altec multi-cell horns, here's a photo of a 1003b I grabbed from a google search: Quote Link to comment Share on other sites More sharing options...
tagger Posted March 22, 2012 Author Share Posted March 22, 2012 How about a wedge and some heavy duty velcro? It might make it easier if you post some pictures. I have used this type of velcro, and it has substantial holding power. I kind of like this idea. It may be tricky adhering the velcro to the top of the 1003b horns due to the dimpled exterior surface, but I think I could make it work. What about wedge material? It would be easiest to determine the correct angle and make it out of wood, but should I be concerned with decoupling the two horns? Maybe some sorbethane or other elastomer between the wedge and tweeter? Quote Link to comment Share on other sites More sharing options...
juniper8 Posted March 22, 2012 Share Posted March 22, 2012 How about a wedge and some heavy duty velcro? It might make it easier if you post some pictures. I have used this type of velcro, and it has substantial holding power. I kind of like this idea. It may be tricky adhering the velcro to the top of the 1003b horns due to the dimpled exterior surface, but I think I could make it work. What about wedge material? It would be easiest to determine the correct angle and make it out of wood, but should I be concerned with decoupling the two horns? Maybe some sorbethane or other elastomer between the wedge and tweeter? After you configure the size and the shape of the wood, you could do the super ball trick? Cut in half and screw them in the bottom of your board with dywall screws, flat side down and then velcro. Paint and you should be good to go. You can get what is called "industrial strength" Velcro, comes in a 4ft X 2in roll it is very strong, make sure it is the original Velcro brand. I am sure it would stick to your Altecs. Quote Link to comment Share on other sites More sharing options...
djk Posted March 22, 2012 Share Posted March 22, 2012 I would suggest mountint the tweeter to a tall bracket attached to the horn throat mounting bolts. Quote Link to comment Share on other sites More sharing options...
tagger Posted March 23, 2012 Author Share Posted March 23, 2012 I would suggest mountint the tweeter to a tall bracket attached to the horn throat mounting bolts. That would solve the problem of decoupling the horns, but how would you design the mount to keep the tweet and mid horn mouths in the same vertical plane? The tweeter mount would need hold the horn a couple feet in front of the mid horn throat mounting bolts. If you look down upon a multi-cell horn, you can see gaps between the horn cells. I suppose I could have some support brackets come up through there... Quote Link to comment Share on other sites More sharing options...
moray james Posted March 23, 2012 Share Posted March 23, 2012 if you made a vertical bracket which attached to the two motor bolts showing on the front top side of the motor (the ones DJK pointed out) and went up vertically and set the tweeter there you could position at any height you like and at the same time align the tweeter diaphragm with the mid diaphragm. That will sound much better than having the mouth of the tweeter and mid in the same palin. I would guess that was the point of DJK's suggestion. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
tagger Posted March 23, 2012 Author Share Posted March 23, 2012 I've got an active crossover to take care of phase alignment, so no need to keep the drivers in the same vertical plane. I wanted to keep the horns in the same vertical plane to avoid early reflections from the tweeter off the mid horn. The Dayton horn has a 80 x 40 dispersion and so might not pose a problem mounted back there, but the baby cheeks horn is 90 x 90. Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 23, 2012 Share Posted March 23, 2012 MJ, I believe is correct. Mounting on the throat mounting bolts would put the two drivers close to being in alignment and imaging will be greatly improved over the tweeter mounted on the front edge of the multi-cell. Bruce Quote Link to comment Share on other sites More sharing options...
tagger Posted March 23, 2012 Author Share Posted March 23, 2012 MJ, I believe is correct. Mounting on the throat mounting bolts would put the two drivers close to being in alignment and imaging will be greatly improved over the tweeter mounted on the front edge of the multi-cell. Bruce I would agree if I was using a passive crossover. My digital crossover takes care of time alignment. If I were to mount the tweeter directly above the 1003b throat mounting bolts, I'd have to raise the tweeter up higher to make sure the tweeter's dispersion pattern can clear the mid horn. But since there's no concern with time aligning the drivers, I'd prefer to mount the tweeter up front, keeping the horn mouths aligned, and allowing me to mount the tweeter lower. Ideally I'd do as Speakerfritz suggested and mount the tweeter coaxial to the 1003b, but it's just not practical with this horn. Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 23, 2012 Share Posted March 23, 2012 My digital crossover takes care of time alignment. I guess we all missed that... [] Quote Link to comment Share on other sites More sharing options...
moray james Posted March 23, 2012 Share Posted March 23, 2012 Sorry I did miss the digital crossover. Have you considered using domr high quality neo magnets to mount the tweeter? You can epoxy some steel washers (or neo magnets) to the horn and make a simple bracket for the tweeter and fit that with neo magnets. If you use a thin vinyl or neoprene disk on the washer and the magnet they will not slip and are rasy enough to remove if you have to. Just a thought. No drilling holes just a little epoxy. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted March 23, 2012 Share Posted March 23, 2012 Not sure what your project is but could you place the tweeter below the Altec Horn or is their a specific reason you want the tweeter mounted above the Altec? Here is an example. I really like the way cut-throat did his Altec/KHorn modification. mike tn Quote Link to comment Share on other sites More sharing options...
djk Posted March 23, 2012 Share Posted March 23, 2012 " Sorry I did miss the digital crossover" Was not mentioned at first, but they don't work the best for people off-axis and for reverberant sound (the mechanical apexes of the drivers being different). Quote Link to comment Share on other sites More sharing options...
tagger Posted March 25, 2012 Author Share Posted March 25, 2012 " Sorry I did miss the digital crossover" Was not mentioned at first, but they don't work the best for people off-axis and for reverberant sound (the mechanical apexes of the drivers being different). Can you explain this a bit more? Do you mean that despite time-aligning the drivers, the apexes of the wave forms will still not be aligned? Quote Link to comment Share on other sites More sharing options...
djk Posted March 26, 2012 Share Posted March 26, 2012 "Do you mean that despite time-aligning the drivers, the apexes of the wave forms will still not be aligned?" Correct. It will not be time-alligned for off-axis listeners, and the reflected sound. Search the JAES for " Apparent Apex" "the apparent apex,https://en.wikipedia.org/wiki/Horn_loudspeaker#cite_note-20'> the focal point of pattern dispersion, was not the same for every frequency " PS Unless you subscibe the the JAES their papers cost a fortune to read online, and are expensive even if you do subscribe. A university library usually has the back issues, I visit U of I or ISU when I need to read the JAES. Quote Link to comment Share on other sites More sharing options...
garyeanderson Posted March 26, 2012 Share Posted March 26, 2012 "Do you mean that despite time-aligning the drivers, the apexes of the wave forms will still not be aligned?" Correct. It will not be time-alligned for off-axis listeners, and the reflected sound. Search the JAES for " Apparent Apex" "the apparent apex,https://en.wikipedia.org/wiki/Horn_loudspeaker#cite_note-20'> the focal point of pattern dispersion, was not the same for every frequency " I think this diagram may help explain what Dennis is getting at. Quote Link to comment Share on other sites More sharing options...
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