m8o Posted December 28, 2006 Share Posted December 28, 2006 Has anyone ever tried an acoustical lens on a mid hor on the La Scala? Specifically, the JBL 2310 Lens, which is 20x7 ??? http://www.jblpro.com/pub/obsolete/Acoustic_Lens_Family1.pdf I have a day to decide how bad I want it. Would love to hear your thoughts on how the Klipsch horn mates to an acoustical lens. If it's a good match, I have to of course consider one on the tweeter then too... [] EDIT: corrected the title (I hope that changes the title on the main thread too) Quote Link to comment Share on other sites More sharing options...
ZAKO Posted December 29, 2006 Share Posted December 29, 2006 I have a pair of JBL serpintine acoustical lens...It works very well...But by todays standards its a klunky way to Spread high frequencies.....Its amazing putting your ear to the side of the unit & hearing the very high frequencies.....No you dont need to place one on a tweeter.....But may be i,ll try that stunt today as an exercize in futility.....The new CD horns have replaced that type of design.....If the cost is low buy them...But you just cant expect good results putting them in front of a Klipsch designed horn. Quote Link to comment Share on other sites More sharing options...
m8o Posted December 29, 2006 Author Share Posted December 29, 2006 Thanx very much. I decided I'm going to go for it. Yes, reading up on the technology I believe it would not work well in front of the K701 and I need a Potato Masher horn with it, as the concentric circle screen they employ enters into the dispersion through the lens --- but I've still wanted one for a long long time for some unexplainable reason so I think I'll pull the trigger. Thanx again. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted December 29, 2006 Share Posted December 29, 2006 The potato masher achoustic lens is not as effective as the slant plate shingle type lens. At some point it acts as a achoustic filter. I believe the ring that holds the perferated elements together are interfering. Try www.jamminjersey .com for pricing. Quote Link to comment Share on other sites More sharing options...
ben. Posted December 29, 2006 Share Posted December 29, 2006 I sold a couple pairs of JBL 2395 at a previous job. Never had time to listen to them, but would really have liked to take a pair and a few drivers for a while. I think they went for around $400/pr. One pair went to Taiwan (surprise) so I had the task of disassembling the unit for flatter shipping. From old JBL literature: <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /> The JBL family of acoustical lenses was originally designed for stereophonic audio systems for motion picture theater application. They were first presented to the industry in 1954. The acoustic lens, which had been described by <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Bell Laboratory scientists Kock and Harvey in 1949, had not previously been applied to commercial sound reproduction. The acoustic lens, as engineered by JBL, was the first real innovation in high-frequency sound reproduction since the early 1930s. The JBL 2395 is a slant-plate acoustic lens for use above 800 Hz. Sensitivity 108 dB. The horizontal pattern of 140 deg is determined by the shape of the plates. The lens is backed up by a 300 mm (12 in) elliptical exponential horn. The 45 deg vertical pattern is closely controlled by the shape of this horn. The lens does not require additional baffling for use above 800 Hz. To insure proper high frequency operation the ends of the lens plates must not be obstructed Operation down to 500 Hz is feasible in motion picture sound systems or where vertical pattern control is not essential, provided a baffle is provided in the vertical plane. The 50 mm (2 in) entry may be reduced with a Model 2327 throat adaptor to accommodate 25 mm (1 in) drivers Nominal Q=3.6 (2 kHz octave band). www.jblpro.com/pub/obsolete/Acoustic_Lens_Family1.pdf Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 The potato masher achoustic lens is not as effective as the slant plate shingle type lens. At some point it acts as a achoustic filter. I believe the ring that holds the perferated elements together are interfering. Try www.jamminjersey .com for pricing. Yes, I've been reading and learning a lot today, from JBL literature and a sister board to this one for JBL: http://www.audioheritage.org/vbulletin/index.php I was mistaken, the Potato Smasher horns and Acoustic Lenses are mutually exclusive. Thanx for the link. Does Jersey have a monopoly on JBL stuff? [] Another place was recommended to me from the AudioHeritage board also in NJ. Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 Unlike the K-horns, I don't see a lot of customized La Scalas. FYI, if I win this and another auction, my La Scalas are going to be transformed. a) I'll replace the existing tweeter with a JBL 077 slot horn tweeter I'll have a 2310 lens over the K701 horn ; will change to a matching horn if the Lens and K701 don't couple nice. c) I'll be tri-amping with active x-over (of course) and custom designed and built transconductance amps made individually to match each horn. [H] Quote Link to comment Share on other sites More sharing options...
ZAKO Posted December 30, 2006 Share Posted December 30, 2006 Yes I too triamp...Electronic crossovers make for quick adjustment Of xover points & slopes...I dont believe the 2310 lens will work on the K701 horn...The JBL 2307 horn & L91 lenz is best .. The round perferated horn/lenz is less popular...The slant plate design lenz is most effective...I have both & measured the results. Remember the Lenz must be mutch mutch wider than the mouth of the horn. Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 ...I dont believe the 2310 lens will work on the K701 horn...The JBL 2307 horn & L91 lenz is best ...... Remember the Lenz must be mutch mutch wider than the mouth of the horn. [:'(] I haven't come across by how much yet, but I'll be looking. Do you happen to have a link to where I might learn the theory about "by how much"? Looks like I'll have to change the horn then too if I want to use a lens; Didn't want to do that. Or maybe use the 2395 lens? . Thanx for the info. (as I sulk away with the wind taken out a bit [:$] ) Quote Link to comment Share on other sites More sharing options...
ben. Posted December 30, 2006 Share Posted December 30, 2006 My recollection was that the mouth of the horn on the 2395 was maybe 10" wide, with the lens portion about 36". I hate to discourage experimentation, but the contour of the front edges of the lens seemed to be suited perfectly to the shape of the horn mouth they're mated to. You may get good results on-axis, but the dispersion characteristics will llikely be pretty wacky. Nothing ventured, nothing learned... Quote Link to comment Share on other sites More sharing options...
TBrennan Posted December 30, 2006 Share Posted December 30, 2006 Why not build your own lenses? The slats can be made of stiff cardboard, Janszen put cardboard slat lenses in front of their electrostatic elements. Quote Link to comment Share on other sites More sharing options...
TBrennan Posted December 30, 2006 Share Posted December 30, 2006 The elements sans lenses Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 Yes, it's interesting to compare polar plots between the 2395 and 2310. Based on just observation from the doc I linked to in the OP, it seems if you just want 1K Hz and up control, a bit under 2:1 lens/horn width ratio or is enough (the lens & horn you mention). If you want wide WIDE dispertion in the 1K Hz or below range, you need the 3:1 ratio of the 2395 lens. Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 Why not build your own lenses? The slats can be made of stiff cardboard, Janszen put cardboard slat lenses in front of their electrostatic elements. ...that's cardboard? ...outside? I'm hoping those are brought in in the rain. [] That is an interesting proposition. The thing that comes to mind about cardboard tho is I think the 'soft' material would result in a lot more loss of the signal then steel slots through resonation and dampening. JBL states only about 1% is lost through their lens. From page 3 here: http://www.lansingheritage.org/html/jbl/reference/technical/lens.htm It's a great read on the theory. I wish for more. I'm just wondering if as cardboard is not as rigid while being transparent to sound, there would be more loss. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted December 30, 2006 Share Posted December 30, 2006 You dont have to go overboard on the size of the lens...36 inch is too big.....I have one set at 10 inch wide & another set Used on the JBL Harstfiend that is about 17 inches wide... Try Jamminjersey.com again he also gives prices on horns like 2307 & 2308 & 2309 etc Plus lens prices.....Now the Hartsfield horn/lens is pricy you dont want to open your wallet that wide. Quote Link to comment Share on other sites More sharing options...
ben. Posted December 30, 2006 Share Posted December 30, 2006 We should point out that you're talking about the mid horn on the Scala (K400/401) and your title has the PN for the HF horn (K700). Quote Link to comment Share on other sites More sharing options...
TBrennan Posted December 30, 2006 Share Posted December 30, 2006 McCauley made horn-lenses too, I used the ones pictured with an 800hz crossover with JBL drivers. They were 130 degree jobs, too wide a pattern to work wellas front speakers in my room but excellent for surrounds, as shown. Though I must admit the main thing was that they looked cool. Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 We should point out that you're talking about the mid horn on the Scala (K400/401) and your title has the PN for the HF horn (K700). I'm in your debt. What a dingaling, and neophite I am. I'll see if I can edit the 1st post and change it. ( edit: I can't [] ) I actually though the K40x is what's used in the Bells and the 70x is in the La Scala; embarrasing. [:$] Quote Link to comment Share on other sites More sharing options...
m8o Posted December 30, 2006 Author Share Posted December 30, 2006 ...p.s. based on what I learned thanx in part to you all, I gave up the fight and let the other bidder who wanted it win the auction.... [li] Quote Link to comment Share on other sites More sharing options...
Guest " " Posted December 30, 2006 Share Posted December 30, 2006 ...p.s. based on what I learned thanx in part to you all, I gave up the fight and let the other bidder who wanted it win the auction.... [li] Yo were probally bidding against the seller..... Quote Link to comment Share on other sites More sharing options...
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