D-MAN Posted October 12, 2006 Author Share Posted October 12, 2006 It's says 14" x 1/2" or 7 sq. inches total as seen in Fig. A (it's only a 12" driver). Interesting, the Klipsch Shorthorn uses a 36 sq. in. slot! Didn't it also use a 12" driver? Something's fishy! Well, not really, this is a much smaller cabinet than the Shorthorn. However, the drawback to the "shorthorn-type" corner rear-loaded enclosures is that the horn itself is very short compared to LF wavelengths, so naturally, it was not as good as some of the other designs that used a longer horn pathway. This isn't altogether bad, though, as mentioned previously, peaky LF response can be exploited or controlled usefully. Unfortunately not in this type of design which cannot take any channel "stuffing" to lessen the reactance. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 There are a bunch of scoop designs, but I find them to be limited to around 50Hz due to horn mouth size and exhaust route (1/4 placement is typical). Here's one... Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 One of the drawbacks of a LF scoop is the footprint tends to be large being that it is a PA-type design, and for domestic use, if it is larger in footprint (say 24x24) than the La Scala, again, is the extra 10Hz of LF extension worth the size and trouble? Here's another of the smaller footprint variety, which I call "full-range small-signal" types, rightly or wrongly... I am very suspicious of the actual LF response of this type of design. Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 H. F. Olson's 1940 patent compound horn... Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 One of the drawbacks of a LF scoop is the footprint tends to be large........ is the extra 10Hz of LF extension worth the size and trouble? YES.... mine at 40 watt's ... wil make you feel like you have to .....[+o(] Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 Duke, that's exactly what I said a ways back - the PUNCH of a cone-in-your-face combined with the LF efficiency of a bass horn! Bass players seem to love the scoops for exactly that reason - well that, and a reasonable SPL+performance-to-footprint ratio! But for domestic use, a scoop design of an appropriately low Fc is likely to be a bit large and will therefore most likely lack the appropriate WAF that a smaller enclosure MIGHT. I guess what I'm saying is that alot of very smart people spent their time designing rear-loaded horns instead of front-loaded designs, ranging from very complicated to the extremely simple, and there must be a reason beyond the historical time-and-place. Evidence points to the fact that the performance is better with a horn hanging off the back than a port, duct, or laborynth, etc. I understand the goal of enhanced horn-loading on the LF response in a smaller package than required for a front-loaded design. The trend towards smaller cabinetry has always been a driving force behind loudspeaker development, and the rear-loaded designs seem to dominate the horn portion of the market, both historically and presently. This is most likely due to the smaller footprint size. I tend to regard the footprint as being the all-important feature rather than the enclosure volume, due to the trend towards the "tall and skinny" direct radiators that abound in the present loudspeaker market. Nobody seems to care how tall they are, they are more concerned with the footprint, in particular with 1/2 or 1/4 space placement currently in vogue. I think that Klipsch-fans tend to ignore the rear-loaders as being some sort of a poor-step-child of the front-loaders, being that the Khorn has apparently outlived all of the large commercial DOMESTIC horn enclosures (with the notable exception being the Altec A7). I think we are needlessly dismissing a whole avenue of potentially good audio if we don't explore the rear-loaded bass horn designs too. Frankly, I have never heard one. Not even one! As far as summarily dismissing horn enclosures due to their large size, I'm already well beyond that consideration, having front-loaded corner horns. So I'm ready to explore the bare-faced cone side of things as long as there is a horn attached! One exciting ascpect is that the modern small-Vas driver available today open up some design possibilities not available in the past. A revisit of some of the better designs of the past seems to be in order... I'm excited about my new design because it is has a footprint of 18x25 - that's slightly larger than the CW. It's alot taller though, but I personally think taller is a good thing. I also show the driver mounted high on the baffle for a 15" coaxial driver, another thing that I have no experience with, but I like the simplicity. DM Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 I have always viewed the RLH enclosure"s ..as the best performers ... the reason I have mine ... well, the scoop peter's out around 150 Hz ... just n time for the Direct Radiator ... to punch you in the gut ....[] i don't see how you can go wrong .. the exact same radiateing frequency's .. come off the back of the speaker, as the front.. why throw it away .. ala KH....[:^)] Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 Do you have any pics or plans to post? As an aside, note in all of the above plans and such that there are no folding treatments employed; this is because you specifically don't want the high frequencies going through the horn. The tortuous folds are used as upper frequency limiters, the more the better. In particular, as seen in the Olsen patent, the use of extra capacitance and losses due to viscosity are purposely employed to limit the upper frequency band pass through the horn. Some employ a felt lining in the horn, as did the JBL Hartsfield in the rear-loaded embodiment (attached). DM Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 A related rear-loaded application... Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 This unusual device is the Helffrich Catenary rear-loaded wall horn in what appears to be a push-pull (isobaric) LF driver configuration... This is a 1/4 space horn (wall), somewhat unusual, as is its expansion type. The picture is shown sideways. DM Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 here'a a small clone of the # 4530 enclosure .. single 15 Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 We have barely scratched the surface of the small-signal variety... Here is an example. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 Saaay .... you wanted tall 'n narrow .....there ya go ......[] 22 X 23 ... smaller than a 'scala my 18's .. are pretty wide, and deep I LIKE Scoop's .... au contrare .. I find them ideal for home use, as they suffer from short throw in commercial .. all done with L.F. at 35 > 40 feet Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 These are Lowther/Fostex, etc. full-range driver rear-loaders... There is a great deal of new horn design activity in this particular market niche. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 I think ya oughtta build that .. single 15 scoop, Dana ... and stop dickin' around with all them complicated design's .....[] Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 Pretty complicated for what it does, of course, but the full-range crowd is pretty devoted to a different sort of audio if I may say so, i.e, these are NOT going to thump you. That isn't what they do. These are not going to be "rockers". Most of the designs are clearly geared towards extreme WAF rather than response, seems to me. Still very nice to look at regardless. I don't necessarily have a problem with that, but think "better than CW" means rocking when desired, which I don't think any of the Lowther-types can actually do. So I think somewhere between the large rear horns of the past and the small-signal types as seen above is an appropriate size to fit between the 40Hz corner horns and the "small-mouth bass" variety seen above. DM Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 and, Yes ... they do fall off rapidly at 40-50 Hz ..... but .... so ... do all those other design's .... Quote Link to comment Share on other sites More sharing options...
D-MAN Posted October 13, 2006 Author Share Posted October 13, 2006 Duke, yeah, I've got my design finished, it just needs to be built. It is roughly around the size you suggest. Comes out approx. 41" tall x 25 w x 18 d with a single 15. I just want to share some of the thinking that went into it with others who might be interested. There is alot to think about. DM Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted October 13, 2006 Share Posted October 13, 2006 Aaaaaahhh... why .. re-invent the wheel ... there's nothin' a few more Watt's can't fix . with any Scoop ....[] Quote Link to comment Share on other sites More sharing options...
jwc Posted October 13, 2006 Share Posted October 13, 2006 I read throught this. Maybe I missed it. Dana, which one is your rear loaded design? Dukester. What is the external dimensions of the 18" scoop? You say it dies in the 40-50Hz? Quote Link to comment Share on other sites More sharing options...
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