gibber

Hi, sorry for a very late addition to this series of posts. I just "recovered" the first of two HR9040a's i recently bought sprayed black (way back when) to glorious & shiny White Whale attire. I believe the shiny surface is part of the success this horn had (& has). Staring down into the flare makes me think even the "A" version of these just about justify calling them slot radiator, if the Smith horn is accepted as being one, having (as the HR6040a/9040a has in part) parallel side walls. The HR 6040/9040 i would class as slot radiators without even the slightest doubt, as they narrow the 1.3"/33mm driver entrance dia to something like a 18mm --well-- slot. The Westlake versions of the Smith horn would add a short non-parallel expansion at their mouth. The EV HR "A" version offered this part after the paralell entrance section in the mid 70's already and didn't need the vanes to achieve broad horiz. dispersion, not even the HR120 had them. The HP series used vanes, and i'd lke to tune in with the recommendation for HP640 as the best of the HP bunch (i tried 2/3/4 digits after the "HP" and prefer HR overall). I still have to listen-compare a HR9040/6040 to "A" series, as the non-"A" are difficult to get over here in Germany. Interesting to read Jim Long's inputs on the White Whale production history. And given my horns were black when received, i have to say they look just like JBL2360's when standing vertically on your workbench with your head in their mouth while scaping away that old nitro-based black paint Both EV original and JBL "adaptation" need a heavy-ish coat on their outside in order to sound good at home when crossed over low, see pic with the author busy on a brace of (good sounding, too!) 2360A's. JBL2360 and 2360B are less in need of this coating, btw -- look for them if you loathe sticky stuff on your fingers

Just stumble overr this thread, @Horatio & rgd the ETF.10 shootout, the meas taken by JMLC at the time were erroneously marked. The driver used was of own composition, mating Altec290 core with 288C diaphragm. In essence, a 288-8G. I took, perhaps unusually, a second horn/driver combo into that 2010 shootout with JBL2353+288-8K and perhaps caused Jean Marie's (may he rest in peace) mix-up of the comp driver names. Pretty evident in the photos the Melaudia / French ETF team took and published. EV's HRx040 and HRx040A series differ significantly in lower mid freq response, see exchange on their history in AudioKarma between AK member abez0 and myself. Those posts were commented on by former EV staff elsewhere and provided here on this forum pointing to the possibility the changes were in fact mainly made due to easier manufacture (this was my initial guess, but the "A" series advantages then led me to believe otherwise). Positive (mid/treble) and negative (lower cutoff) side effects of changing the HR series' initial expansion were maybe overlooked at launch as the majority of the horn bell, the parts facing the listener, stayed unchanged in expansion/shape. My (unconfirmed) guess is that when launching the "A" series, these went out from EV with data sheets previously compiled by Don Keele and actually show the non-"A" series radiation pattern details. Can some light on this be shed by someone more knowledgeable here, maybe?

Thanks for the clarification, Greg. Your findings were further followed up by member Horatio and help to get a clearer picture regarding the white whales. Special thanks for the tip-off regarding the non-"A" response graph in the 1975 Keele paper (driver equalized flat in plane wave tube) : ( hope the picture appears here, upload seems a little tricky on this site ) I have not come across a HR9040 data sheet, whereas the one for the HR9040A is readily available. Form discussions elsewhere it is apparent that the HR9040A initial exponential expansion has twice the cutoff of HR9040A. What doesn't make it's way into the horn won't make it through to the exit, so clearly a HR9040 is preferable in applications where low cutoff is a goal. But this advantage comes at the price of the narrow (18mm only) slot feeding the 40deg angle the side effects of which may warrant a seperate tweeter in demanding applications. The pressure results in the graph above seem to confirm this in the range 2 to 7 kHz, more so from 7 to 10 kHz). I suspect the 38mm wide "slot" in HR9040A won't cause side effects so severe. What's still needed for completeness is a response comparison between the versions, big Q : is there someone that measured both horns with the same driver? -- or did anyone come across a response graph for HR9040A taken with a driver that was equalized flat on a plane-wave tube prior to measurement on the horn... Ralph

Very inviting photo of a comfy-looking setup. The white whales look great. Don't know why Jim Long's HR9040A horns don't have the central fin ... where the white whales ever sold that way or did he take them from the production floor before the center brace was glued in? They look better this way. There's not much below 500Hz in the "A" versions of the 90 or 60 deg whales. For two way use, the early producion version without the "A" allows lower cut-off with the trade-off that the diffraction slot is acting more prominently. HR6040 or 9040 have the 1.5" high but 4" wide sticker (the "A" versions have the upright sticker) For those that are sensitive to apparent apex shift and/or distortion effects associated with narrow slot fed CD expansions: HR6040A sports the most gradual opening and in my view is the best of them all by a narrow margin (plus added WAF - it's 7" less wide than HR9040A). Another way of expanding bandwidth (both upper and lower freq) is to follow Keele's 1973 AES paper and go for lowest Qes drivers you can find. DL10X as used in the H11 are a good starting point. These drivers are actually used for midrange typically and this path, if taken to the extreme, can lead you to finding even better drivers. Why not go for pro mid ranges and get more low extension while doing so, just as Keele's TSP-based write-up of classic horn theory predicts. Avoid highish Fs, though. Beyma 102Nd (or 122Nd if space allows 12") offer Q values below 0.1, but there are others and most are cheap enough if anyone just wants to give it a try. greetings !