slovell Posted July 18, 2012 Share Posted July 18, 2012 Has anyone tried putting insulation in their 5.5's? I know they came with a loose piece just stuffed inside that kept falling down and blocking the port in mine. I eventually took it out. I wonder if it was meant to isolate the tweeter inside the cabinet? Has anyone tried installing a baffle between the tweeter and woofer sections? Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 18, 2012 Share Posted July 18, 2012 your horn is a closed back device there is no radiation into the inside of the cabinet therefore no need of a baffle. a baffle would reduce the volume your woofer sees which is not a good idea. a little adhesive or a staple will keep the foam damping where it needs to be up in the top portion of the cabinet. you don't want damping in the bottom section of the cabinet as you want resonance down there because that is what drives the reflex vent into action. If you want to try something try blocking off the vent to see what you think of the woofer in a sealed box. Give it a little time so you can adjust to the difference. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 19, 2012 Author Share Posted July 19, 2012 Thanks for the reply. I wasn't sure where the stock foam was supposed to be located as it had fallen down in both speakers. I'm going to try the sealed box trick and hear what happens. When I discovered the fallen foam, which was dry rotted and unusable, I was installing Crites crossovers and titanium diaphragms. While I had the drivers out I lined the insides of both cabinets with a layer of thin acoustic foam. If I'm understanding you correctly I should remove that material from the area around both woofers and leave it in the upper portion of the cabinet? Or should I try to cut a piece of foam that compares to stock and put it back where it was located originally (which I'm not sure of) and go from there? Best Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 19, 2012 Share Posted July 19, 2012 Sam: my guess is that a thin layer of foam on the inside walls will not be a problem as that will still allow for cavity or volume resonance which will be sufficient to drive the reflex vents. Please keep us posted as to your experiment with the vent and tell what you think about the sopeaker as a sealed design. You may well lose a little output level at the vent frequency but you will gain significant bass extension as a vented cabinet rolls off at twice the rate of a sealed design below resonance.If you decide that you like the cabinet sealed and decide to keep it that way then you can experiment further with volume damping to increase the apparent volume of the cabinet and perhaps extend your bass response further. fiberglass is your best and least expensive option for volume damping the cabinet. You will have to experiment with quantity to see what works and when you have added too much and you actually start to lose bass. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 19, 2012 Author Share Posted July 19, 2012 I used sleeping bag matress foam which is fairly dense and about a half inch thick trying to keep the internal volume of the cabinet close to factory specs. I was trying to deaden the cabinets a bit to lessen their hollow sound. It does seem to improve that somewhat. I also filed away some of the plastic material on the tweeter diaphragm baffle to open up the highs more, they always sounded too diffuse and unfocused to my ears and it did improve the top end focus. I've considered removing the tweeter baffle altogether but thought this might introduce more of the shouting effect inherent to the horn than would be desirable. I'm assuming the easiest way to plug the port would be with a piece of foam rubber which would be easily reverseable. I love these old speakers, I bought them new in '96. The Crites upgrades are a definite improvement but I want to get everything I can get out of them. I was chasing a pair of KLF-20's recently but nothing came of it, the seller stopped replying to e-mails concerning shipping. I'd really like to find an affordable pair of these and restore them, I've read they're like 5.5's with midrange. Best Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 19, 2012 Share Posted July 19, 2012 Just a spot check on the foam that you are using, is this open cell or closed cell? sleeping bag and camping sleeping rolls are usually closed cell. If this is closed cell remove it and replace it with open cell foam otherwise you are only eating valuable cabinet volume and not damping. Internal side to side front to back bracing is the best way to clean up the sound of your speaker. Can you post a picture of what it is that you did with your horns? A solid block covering the vent hole with some sort of thin gasket is your best bet. I will guess thet with a seaed box you will lose some of the jack hammer impact the 5.5 has but you will trade that for a smoother more extended bass which rolls much more smoothly. Which you like will be up to you. I would suggest that you keep your eyes open for a pair of CF3. the other possible option would be to find a larger CD horn and build a pair with the parts that you have now, something to consider. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 20, 2012 Author Share Posted July 20, 2012 This is what i did to the tweeter baffle. I filed away about 50% of the plastic covering up the diaphragm. Quote Link to comment Share on other sites More sharing options...
moray james Posted July 20, 2012 Share Posted July 20, 2012 Sam without a berore and after picture it is had to know what was removed. I assume that you opened up further the existing open ares which cover the diaphragm ? Not sure I would have done that but if you are happy with the results? How are they at levelnow? I would be concerned that you have removed necessary load from the diaphragm. I have kept my horn modifications to dealing with smoothing sharp edges removing casting flanges making openings which are not round but which are supposed to be round round and damping under the diaphragm and in the throat of the horn with 15 ppi open cell foam.I suppose if you wanted to replace the filed out material it would not be all that difficult to do so no harm done either way. Glad you like the results. Thanks for thepicture. If you have some open cell foam try lining the front edge of the horns on the left and right side vertically with a slice of foam about 1/2 inch thick and about an inch deep into the horn from the mouth edge and see what you think. You can also try this along the two horizontal edges of the mouth. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 20, 2012 Author Share Posted July 20, 2012 I've got a couple of unmodified tweeter baffles around somewhere, if I can find them I'll take a photo and post it later today. I like the sound from the modified baffle, it sounds more focused in the soundstage to my ears. Best regards, Sam Quote Link to comment Share on other sites More sharing options...
slovell Posted July 20, 2012 Author Share Posted July 20, 2012 It doesn't show up as well against the poly diaphragm but this is the best I can do. Best Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 20, 2012 Share Posted July 20, 2012 thst's good it is cler to see what you did tanks for making the effort to post I am suer it will help others to see too. The poly diaphragms are not very good when compared to a phenolid and even worse when compared to a titanium. What about your foam in the cabinet open or closed cell? you can damp the body of your horn with dynamat which will sound good and you can slap a layer of dynamat on the back side of the horn driver as well which you should notice. Then it's time to brace your cabinets. Have you tried blocking the vents yet? Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 20, 2012 Author Share Posted July 20, 2012 The foam I used is closed cell. You're correct about the titanium diaphragms, the others don't even compare. I tried the rope caulk trick once on the horns but did'nt care for it, it sounded a bit too dull for me. I'm going to close off the ports later tonight and give it a go, should be interesting. I'm going to try this and see what effect it has before I pull all the speakers to replace the insulation. Best Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 21, 2012 Share Posted July 21, 2012 Did you try the rope caulk lenses with poly or ti diaphragms? Damping the horn lense damps its physical resonances so they generate less output. That has to be good as the ohly thing that you want to hear is the diaphragm moving air. Resonant vibrations are noise. You can't fix the sound of your speaker by adding noise.Felt daming at the horn mouth can be very benificial as can subtle damping in the throat of the horn How did things go with the vents blocked off? Looking forward to your comments. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
slovell Posted July 21, 2012 Author Share Posted July 21, 2012 It was a mixed bag, improvement in the midbass but a definite loss in low bass. At low to medium volume it sounded pretty good but when I turned up it sounded degraded with a bit of distortion like the enclosures were trying to do something they were'nt designed for. OTOH just closing off the port doesn't exactly make it a sealed enclosure, one would have to chase down and eliminate all leaks. If memory serves, sealed enclosures are generally much less in internal volume (at least in subwoofers) than ported ones. In this vein, adding extra insulation would only make matters worse. I tried the rope caulk with the poly diaphragms. I'm going to Dynamat the horns and try your suggestions with the foam or felt in the throat first. Cheap and fun. Best Regards, Sam Quote Link to comment Share on other sites More sharing options...
moray james Posted July 21, 2012 Share Posted July 21, 2012 Well with a speaker with such solid bass impact at the tuned frequency you know that will go away as soon as you block the venting. Sealed cabinets have to be large if you want bass extension and that is why you normally see them fully stuffed to maximize apparent volume to the woofer. I would say pull the closed cell foam as it is not doing you any favors and fill the inside of the cabinets with good old fiberglass pink. Dont over stuff just fill the box vloume and see what that gives you for bass extension If you finf the filling has overdamped and that you have lost bass extension remove about 25% and listen again. You should be bery close with a full box not packed or stuffed just taking up the volume there with the pink. You should be able to block off the vents with a small piece of sheet stock odf any kind handyIf you use a simple piece of strapping inside longer than the width of the vent cut out then you can use a long screw and tuck the strapping in to the cabinet across the holed and tighten up the screw to hold it tight to block off the vent hole. Felt works great in the horn mouth and large open cell foam works well in throats you can also use a small piece of poly batting in the throat just enough to lightly fill the first 3 inches will do well. the best felt is 100% wool synthetic felsts are very poor. The best felt is SAE rated F11 acoustical felt which has the widest absorption coefficient and the greated amount of damping, it is not expensive and worth every penny. Improvement in the midbass is well worth it as these speakers need a sub anyway and the exagerated bass of the vented version is well lost if you combine the speakers with a quality pair of subs. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
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