FranJ Posted January 10, 2011 Share Posted January 10, 2011 This will be my summer project. My LS are very much beaten up and old. They've been transformed to a split industrial-like design. I'm thinking of refurbishing them, and add something over-the-top to the design: what about doubling all external sides of the bass bin, leaving a free space between the wooden panels and filling up that empty space with sand? it's sometimes done on high-end bass bins incl. Onken and others. Of course the weight is gonna be a problem. Otherwise, I guess it could make the most neutral sounding LS bassbin ever. Any thoughts? here's some drawings i've made. please notice that this is just primary drawing, likely to evolve into something different, but I thought I'd share it and see what you guys thinks about it. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted January 10, 2011 Share Posted January 10, 2011 An easier and probably more effective strategy is to 1) add bracing, and/or 2) adhere a 1/2 inch panel to the top and sides (look up constrained layer dampening - CLD) Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 10, 2011 Share Posted January 10, 2011 a common belief is that if you stiffen the cabs you will get more bass out of them....problem is it's not efficent bass....your better off redirecting your efforts into building a sub like the klipsch kp-480. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted January 10, 2011 Share Posted January 10, 2011 a common belief is that if you stiffen the cabs you will get more bass out of them....problem is it's not efficent bass....your better off redirecting your efforts into building a sub like the klipsch kp-480. SF, you are of course correct that a sub is a better solution. However, I disagree about the the consequence of stiffening up the cabinet. The energy from the transducer can either produce SPL or it can vibrate the cabinet. So a more solid cabinet is still a good idea, if there is a drop out in the bass. BTW, the OP never said he was worried about a lack of bass. The lack of bass in the LS is a consequence of the horn's design (compromises on the flare, length & mouth). That can not be changed. However it can have a larger back volume and be ported if you want to augement the cabinet. Plenty of threads on that topic. 1 Quote Link to comment Share on other sites More sharing options...
Islander Posted January 10, 2011 Share Posted January 10, 2011 One member posted in the last few months how he'd built altogether new bass horns for his La Scalas. They were deeper and flared out at the front, so they were also wider than the originals. The bass curve he posted did look like an improvement. If you're going to do a bunch of woodworking anyway, it might be something to look into. Quote Link to comment Share on other sites More sharing options...
FranJ Posted January 10, 2011 Author Share Posted January 10, 2011 I'm not looking for more bass. I'm using an active sub to cover the lower frequencies. however, my ears are sensitive to some resonances at some frequencies -my guess is between 60 and 150Hz- that I would like to eradicate. Plus my LS bassbins have seen better days and need some youth cure... Quote Link to comment Share on other sites More sharing options...
Islander Posted January 11, 2011 Share Posted January 11, 2011 That's not a resonance you're hearing, it's a peak in the 145-150Hz range due to the geometry of the bass horn. You can EQ it down to get rid of it, but stiffer or braced sidewalls won't change it. The sidewalls of the bass horn do move with the music, but I don't think you can hear that. Quote Link to comment Share on other sites More sharing options...
justinsweber Posted January 11, 2011 Share Posted January 11, 2011 I have a split LS now. Started life as a La Scala. I added 1/2 baltic to the whole bass cab... sides were 1/2 longer ... so the bottom became keyed in. I then added a 3/4" cutout for the doghouse... thus making the bottom keyed a second way as well. All these efforts were a bit much, but I did think the bass response was cleaner... No vibration from the cab. Many feel that if you thicken the cab, you will not need to brace the mouth of the horn too. I think the sand idea is a waste... but adding material will let you stiffen it... and help you refinish the look of the speaker. Quote Link to comment Share on other sites More sharing options...
FranJ Posted January 11, 2011 Author Share Posted January 11, 2011 I wouldn't brace the horn like i've seen it many times. IMHO it doesn't damp the vibrations, it just displace them to HIGHER FREQUENCIES where they're even more nasty on the ear... At least, the one braced LaScala I heard had a resonance peak that really sounded like cardboard. Maybe the work wasn't done properly, and probably if you add material around it then works good; maybe i'm just being over-picky... Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 11, 2011 Share Posted January 11, 2011 I sat in front of mine once with my head almost in the bin. I could take my hands and press inwards on the outside of the bins and could hear the bass become more defined. At that point I knew what all the fuss was about concerning bracing the cabinet. I took a more passive approach and crossed them over at 70Hz. Everything from 70 Hz down goes to a small horn loaded sub. I got to keep my stock cabinets and tighten (and extend) the bass. The Lascala bass bin sides don't vibrate a fraction of what they once did. Quote Link to comment Share on other sites More sharing options...
FranJ Posted January 11, 2011 Author Share Posted January 11, 2011 Makes sense, yes, and I thought about that; but I'm a "straight wire with gain" guy, so the less things in the way of the signal the better I feel. I don't want to put an active crossover in front of my amplifier just to send the low bass away. Would consider doing it if I had a small amp, to release it of some stress,or if I was considering a true active system -in wich case the plus points of having no passive crossovers in the speakers, and no intermodulation, overcomes the minus point of having an active device between preamp and amp... The problem with dampening is that, done wrong, it gets worse, not better. Some materials just have a higher resonance frequency, and the more you go into the mid frequencies, the worse it is, and the mor difficult it gets to annihilate. (I'm just quoting things I've read on DIY loudspeakers forums and magazines...) Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted January 11, 2011 Share Posted January 11, 2011 Fortunately for me, my preamp has 2 sets of outputs. One normal (full signal), and one with a set 70 Hz crossover. It's just a matter of which signal you send to your amp(s). There's corresponding subwoofer outputs. Quote Link to comment Share on other sites More sharing options...
vindeville Posted January 10, 2012 Share Posted January 10, 2012 I am hearing this in my LaScalas that I have recently been upgrading the cabinets on. I hear a resonance on some material like Kralls voice sometimes and some guitar/upper bass guitar gets a little hooty or resonant sounding. When I listen to Metallica I get some strange resonance happening with the thick upper guitar sounds...almost sounds like an issue with sound reflections within the bass horn. I have added 3/4" more material to the bass bin sides as well as the typical wing brace inside the horn. I am also inclined to think the wing brace does tighten up the bass/mid bass but the resonance frequency is moved up higher and may make things worse in other ways. I am thinking oI may remove the wings and listen without them for a while...I was also thinking of a paintable sound deadener within the bass horn or part of it. I love my LaScalas with the exception of this issue on some material that i listen to. I also have had issues with the bass quality of klf 20's prior so some of this may be room related...although my Fortes were never as much of an issue. Would like to add that I have ALK universals and crites tweeter in these. Again they are fantastic sounding most of the time and If I could get this issue under control I would be floored by them( I am going to get Daves Fastracs for them soon though). Any thoughts or ideas on getting this resonance under control would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted January 10, 2012 Share Posted January 10, 2012 Any thoughts or ideas on getting this resonance under control would be greatly appreciated. a lascala cab is a 51hz hi pass horn. you should send frequencies below 51hz to a subwoofer if you need deeper bass rather than trying to force the driver into greater excursion in an attempt to extended the frequency response below 51hz. The impedance of the lascala bass bin rises to 16 ohms at 35hz. it's never going to keep up with the efficiency of the reset of the system. Your just generating a lot of heat and resonance. Adding braces or filling the cab with sand won't extend the frequencies below 51hz and won't lower the impedance below 16 ohms. Quote Link to comment Share on other sites More sharing options...
vindeville Posted January 10, 2012 Share Posted January 10, 2012 My reasoning for beefing up the cabinets was to improve bass/midrange quality...which has worked for the most part. I have/had no notion of getting more or lower bass from my LaScalas. I run a quality subwoofer with my La Scalas for bass extansion below 50hz. I do not use tone control or augment bass in any other fasion, I think the LaScalas bass is phenominal in its quality with power thats comparible to live music, The sub just completes the package. My only issue is with some upper bass/lower midrange resonance I cant put my finger on that some listening material stimulates...like the lower register of Dianna Kralls voice (girl in the next room cd) sometimes....it may be something I just have to live with but am hoping someone here relates and has found a solution if any exist. Quote Link to comment Share on other sites More sharing options...
Quiet_Hollow Posted January 10, 2012 Share Posted January 10, 2012 My only issue is with some upper bass/lower midrange resonance I cant put my finger on that some listening material stimulates...like the lower register of Dianna Kralls voice (girl in the next room cd) sometimes.... Cross check this with multiple playback devices first (someone elses stereo system, heaphones, etc...) It very well could be in the source material. I also happen to own this album. What particular passages are giving you "the sound"? I'd like to investigate this too. Quote Link to comment Share on other sites More sharing options...
vindeville Posted January 10, 2012 Share Posted January 10, 2012 on the Krall cd its very noticable on track 5 when her vocals come in at start of song...less so on track 2 beginning and very slightly track 1 as well as some other spots in other couple of tracks on cd...its funny this is a great sounding cd to me, especially piano tones which you would think would show the resonance also . I do see where the energy at the frequencies in question could give a speaker some trouble and i do notice it on my fortes but in a more natural way...just seems too excessive and weird on my LaScalas....or I'll say it sticks out to me as odd sounding on the ls. Thanks for you interest and looking forward to your further thoughts. Quote Link to comment Share on other sites More sharing options...
Islander Posted January 10, 2012 Share Posted January 10, 2012 On the DVD The Strat Pack, I heard an upper-bass peak that accentuated drum beats in an annoying way. After I converted the La Scalas to JubScalas, the Dx38 settings got rid of that peak and everything sounds smoother and more realistic now, with no mods to the cabinet. The time-alignment provided by the delay units in the Dx38 helps the clarity of the sound, too. Quote Link to comment Share on other sites More sharing options...
kg4guy Posted January 10, 2012 Share Posted January 10, 2012 I recently put braces in my La scalas and am pleased with the results they do have a little more punch . Quote Link to comment Share on other sites More sharing options...
sootshe Posted January 10, 2012 Share Posted January 10, 2012 I've been through pretty much what has been covered here, in terms of the resonance coming from the bass bin and this is not in relation to getting the LS to play lower, but rather to get the best sound from what is there. .................Let me say first that if you haven't converted to one of the more popular mid range horn options & another alternative crossover, then the resonance from the bass bin might be the least of your troubles........................................................Once I'd cleared up those 2 issues, I realized that the bin braces just weren't stopping these resonances & I firmly believe that they are coming from the cabinet.................................................It shows up as others have described, in voice reproduction & was most sensitive to me with some styles of electric & acoustic guitar, at particular frequencies, making the speakers almost unlistenable to my ears...............................so, what to do...............................because I could feel & hear the resonance coming from the actual cabinet & to a certain extent reduce it by putting pressure on the side walls, I took the approach of adding mass to both the side walls & also the rear of the cabinet where the sound pressure is likely to be at it's greatest................where the 15 inch woofer pushes that huge amount of air out into the rest of the cabinet.....................I did this by adding another layer of 18mm ply to both sides & the rear with constrained layer damping of "Green Glue" between the panels & about 50 screws to hold each panel.......................................then the complete cabinet was totally re veneered again to preserve the finish ( a real pain to do....but worth it).................................and the result?.....................I couldn't be more pleased....................maybe I was lucky, but this has transformes the sound of these bass bins............the bottom end is soooo clean & powerful ........and the resonance? ........completely gone......................has it shifted to a higher frequency?............don't know, don't care..........they just sound soooo good now. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.