Re: Re: Change of plans?
Please help me out, Earl, because I'm not fully understanding the attraction of Abbey_plus. I'm guessing that a fair approximation of the Abbey_plus performance can be made by essentially grafting the <1kHz portion of the ESP12 measurements to the >1kHz portion of the ESP15 measurements. Close enough, or am I missing something? If that is the case, then it seems clear to me that Abbey_plus will not measure equal to or better than Lidia15, and may also sound perceptibly inferior. To me that means that the significant potential advantages of Abbey_plus are predominantly in size and price, not sound quality when compared to Lidia15. That, of course, raises two immediate questions: 1) Will a 15" waveguide paired with a 12" woofer really result in a package significantly smaller than a 15" waveguide paired with a 15" woofer? 2) Will a 15" waveguide paired with a 12" woofer really result in a package significantly less expensive than a 15" waveguide paired with a 15" woofer?
I'd appreciate it if you could answer those questions with some real numbers, because without those numbers it is hard to evaluate just how much is being traded-off in going from Lidia15 to Abbey_plus, whether Abbey_plus really makes sense, or whether Lidia15's better measured performance is actually worth a little more size and a little more expense.
gedlee said:
Please help me out, Earl, because I'm not fully understanding the attraction of Abbey_plus. I'm guessing that a fair approximation of the Abbey_plus performance can be made by essentially grafting the <1kHz portion of the ESP12 measurements to the >1kHz portion of the ESP15 measurements. Close enough, or am I missing something? If that is the case, then it seems clear to me that Abbey_plus will not measure equal to or better than Lidia15, and may also sound perceptibly inferior. To me that means that the significant potential advantages of Abbey_plus are predominantly in size and price, not sound quality when compared to Lidia15. That, of course, raises two immediate questions: 1) Will a 15" waveguide paired with a 12" woofer really result in a package significantly smaller than a 15" waveguide paired with a 15" woofer? 2) Will a 15" waveguide paired with a 12" woofer really result in a package significantly less expensive than a 15" waveguide paired with a 15" woofer?
I'd appreciate it if you could answer those questions with some real numbers, because without those numbers it is hard to evaluate just how much is being traded-off in going from Lidia15 to Abbey_plus, whether Abbey_plus really makes sense, or whether Lidia15's better measured performance is actually worth a little more size and a little more expense.
Re: Re: Re: Change of plans?
You are mostly correct, but posting real numbers is not something that I am prepared to do for a hypothetical situation. I can mate the twelve with 15" waveguide in a simulation, but its different than simply matching the ESP15 > 1 khz to the ESP12 < 1 kHz. Thats only a rough approximation of what really happens.
The Abbey_plus WOULD NOT BE significantly smaller than a Lidia15. The Abbey_plus would be a little less expensive than the Lidia15. The actual numbers here are irrelavent until such time as I decide to actually make a 15" mold. The 15" waveguide is a lot bigger than the 10" and much more difficult to fabricate. The ability to do it myself within my resources is questionable. Having it done elsewhere makes the cost prohibitive.
I ruined my first 10" mold and now I am making two more. But that delayed me a couple of weeks.
The biggest problem with the ESP15 is its size, and the narrowing of the polar response at 1500 Hz. The 12" woofer in a new enclosure helps out both these problems a great deal. But yes, the 12" woofer has some problems that we don't see in the 15". Which is the better tradeoff is not clear and I would not do an Abbey_plus if it is not better than the Abbey. But the bottom line is that the Lidia15 is unlikely to have much appeal to most people. My idea is to keep the Summa available for those people who really want the best - and are willing to pay for it. Maybe a kit - but the enclosure price quadruples when it molded in glass.
MEH said:
You are mostly correct, but posting real numbers is not something that I am prepared to do for a hypothetical situation. I can mate the twelve with 15" waveguide in a simulation, but its different than simply matching the ESP15 > 1 khz to the ESP12 < 1 kHz. Thats only a rough approximation of what really happens.
The Abbey_plus WOULD NOT BE significantly smaller than a Lidia15. The Abbey_plus would be a little less expensive than the Lidia15. The actual numbers here are irrelavent until such time as I decide to actually make a 15" mold. The 15" waveguide is a lot bigger than the 10" and much more difficult to fabricate. The ability to do it myself within my resources is questionable. Having it done elsewhere makes the cost prohibitive.
I ruined my first 10" mold and now I am making two more. But that delayed me a couple of weeks.
The biggest problem with the ESP15 is its size, and the narrowing of the polar response at 1500 Hz. The 12" woofer in a new enclosure helps out both these problems a great deal. But yes, the 12" woofer has some problems that we don't see in the 15". Which is the better tradeoff is not clear and I would not do an Abbey_plus if it is not better than the Abbey. But the bottom line is that the Lidia15 is unlikely to have much appeal to most people. My idea is to keep the Summa available for those people who really want the best - and are willing to pay for it. Maybe a kit - but the enclosure price quadruples when it molded in glass.
gedlee said:
If we accept that as true, I guess I'm having a hard time figuring out why Abbey_plus would be any more appealing. You say there would be no great difference in size between Lidia15 and Abbey_plus, and only a small difference in price, so just what consumer fault does Lidia15 suffer from that Abbey_plus does not? Why might you choose to offer an Abbey_plus kit and not a Lidia15 kit? I just don't get it.
MEH said:
If only one of the two is offered, as is likely, then the one with the greater appeal makes the most sense. Thats going to be the smaller and cheaper one. Whats hard to understand?
And, as I said, I have molds for the full Summa if thats what a customer wants, but then its a big jump in size and price.
Here's some food for thought.
The Summa uses a 15" woofer and a 15" waveguide because this combination is ideal when crossing over from the waveguide to the woofer. The ESP10 uses a 10" waveguide and a 10" woofer for the same reason. Yet there's nothing to stop you from putting the *woofer* in a waveguide. For example, you could use a 15" waveguide with a 12" woofer which is ALSO mounted on a waveguide.
One option I'd considered was an eight inch woofer in a 15" waveguide, paired with a compression driver on a 15" waveguide. This combination wouldn't have the sensitivity of the "real" Summa, due to the inefficiency of the woofer. But the use of an eight inch woofer would simplify the crossover, and would be significantly cheaper. (The woofer in the Summa is uber-expensive.)
The Summa uses a 15" woofer and a 15" waveguide because this combination is ideal when crossing over from the waveguide to the woofer. The ESP10 uses a 10" waveguide and a 10" woofer for the same reason. Yet there's nothing to stop you from putting the *woofer* in a waveguide. For example, you could use a 15" waveguide with a 12" woofer which is ALSO mounted on a waveguide.
One option I'd considered was an eight inch woofer in a 15" waveguide, paired with a compression driver on a 15" waveguide. This combination wouldn't have the sensitivity of the "real" Summa, due to the inefficiency of the woofer. But the use of an eight inch woofer would simplify the crossover, and would be significantly cheaper. (The woofer in the Summa is uber-expensive.)
Patrick Bateman said:
John
The part of this that doesn't work for me is that the waveguide would be very short in your example. That makes it kind of unpredictable. The idea could work, but I would suspect that the development to successful implimentation would be massive.
A direct radiator on a waveguide does not have a match to the wavefront that the waveguide wants to see so there will be a lot of HOMs generated. Now in a long horn the HOM do not propagate very far if they are below cutoff. So in a long waveguide the HOM fall off below cutoff to zero, but in a short horn they could reach the mouth as what is called evanescent waves (which deacy exponentially). Bottom line here is that it is just not prediactable what the directivity of a short waveguide on a smaller direct radiating driver would be. A piston driver is highly predictable.
Trial and error could develop this to being a viable approach, but I suspect that it would be a lot of iterations to get it right. First pass success would be shear luck. Development time for a product is the single biggest cost, although the costs of making all those waveguides would also be substantial.
I've thought of this concept myself before, but the development issues scared me away.
I also know how to correct the axial hole in the waveguide, but once again development costs prevent my pursuing that.
A classic example is the new "Arial", its been over a year and nothing has yet been built and tested. I suspect that with usual development iterations it will be another couple of years before we have succesful results from this endeavor.
There is no end of the things that we can "try", but the smart engineer stays fairly close to what he knows "works". Each modification is one step better and in that way we can get to an ideal. The problem here is that big companies, who can readily do this kind of advanced development, don't take any risks and aren't really interested in progress, only profits. The very real problem is that development in a product like loudspeakers is not going to be very fast and sometimes not even at all.
Elliminate the Summas and how much change has there been in the loudspeaker market? Not much. Does that imply that they can't be improved. Hardly. It implies that there is no interest in improving them.
gedlee said:
What is hard to understand is that when I previously asked you whether Abbey_plus would be significantly smaller or cheaper than Lidia15, you said "Abbey_plus WOULD NOT BE significantly smaller than a Lidia15" and "Abbey_plus would be a little less expensive than the Lidia15." As I said before, it is very hard to get a sense of the relative trade-offs with no numbers to work with, but the preference for Abbey_plus over Lidia15 still remains hard for me to understand. If the customer/DIY-builder wants smaller and cheaper, there's Nathan10. If he wants something else, it seems to me most likely that he is willing to accept larger size and somewhat higher price in order to get better sound quality. If Lidia15 is comparable in size to Abbey_plus and not significantly more expensive than Abbey_plus, it doesn't make sense to me that the better measuring Lidia15 would be much less attractive to that I-don't-want-Nathan10 builder than would be Abbey_plus.
At this point I can only make sense of your claims with some combination of the following four: 1) My own sense of value is wildly at odds with most other DIY builders; 2) Abbey_plus really would be significantly smaller than Lidia15; 3) Abbey_plus really would be significantly less expensive than Lidia15; 4) Lidia15 really wouldn't measure any better than Abbey_plus; rather, the two would have similar magnitude variations in frequency response and directivity, just at different frequencies. I must confess that I don't have much of a clue which of these four is the dominant factor making Abbey_plus more attractive than Lidia15 in your estimation of likely customer preferences.
MEH said:
Its 1) and 4). I already said that 4 would likely be the case. 1) comes from experience - what customers say they want and what they will actually put down their money to get are usually two vastly different things. I am not willing to take the financial risk on the Lidia15s until I know that I won't be loosing money. DIYs don't particularly care about loosing money - especially not mine.
Thanks, Earl, now it makes better sense. If, in terms of sound quality, Abbey_plus isn't so much inferior as just different from Lidia15 while at the same time being a bit cheaper, then it finally makes sense to me to bias your decision toward Abbey_plus.
Two last questions, then I promise I'll shut up for a while. 1) What do you anticipate that the sensitivity of Abbey_plus will be? 2) Is there anything to be gained in a Nathan_plus (12" waveguide/10" woofer) or Nathan_minus (10" waveguide/8" woofer)?
Two last questions, then I promise I'll shut up for a while. 1) What do you anticipate that the sensitivity of Abbey_plus will be? 2) Is there anything to be gained in a Nathan_plus (12" waveguide/10" woofer) or Nathan_minus (10" waveguide/8" woofer)?
Just a random thought...a bit OT, but not too much...
Ever considered making a milled throat piece for your waveguides out to say 4" (or whatever gets you to say some episilon from 45º)? The throat piece could be milled from aluminum or something of that nature and have ready made driver attachements. Then the throat could match up to whatever size waveguide you wanted. You'd still need a mold but it would be more interchangeable, etc.
Ever considered making a milled throat piece for your waveguides out to say 4" (or whatever gets you to say some episilon from 45º)? The throat piece could be milled from aluminum or something of that nature and have ready made driver attachements. Then the throat could match up to whatever size waveguide you wanted. You'd still need a mold but it would be more interchangeable, etc.
chrismercurio said:
While I tend to agree with Chris, for those feeling cheated by missing the full home theater multi-channel experience, there is another option.
If the room is wide enough, run an identical pair of enclosures immediately flanking the screen, and wired in mono. The phantom image created will be centered both horizontally and vertically. The trick of course is to maintain the same timbral and dynamic characteristics of the mains, while avoiding the temptation to downsize this pair to fit the room aesthetics / space.
Of course it would be nice to have a pro-grade projector and acoustically perforated screen to allow placement of the entire audio front row out of sight, but few of us have that option.
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