No hard feelin's, Ed. Just had to say that, just for fun.

Bob

So very true! Heres a quicky method (accurate, no way, but it gives an idea of a basic BLH low FR concept). Take the tuning length until just before the final flare section. Calculate the TL response based on 1/4 wave action(straight TL), add 10 Hz. This will give the lowest frequency (approx) when wall/floor loaded. Corner loading will mean subtracting 10 hz.(given the proper room dimensions). Even Dr Bruce has stated that 1/8 mouth size had never given the calculated response when corner loaded.
Yea, its a rough silly Kentucky windage/SWAG type calculation, but i have found it to be very close in many horn designs.
In my designs and sims i see that 1/4 wave gives the lowest initial boost then horn action kicks in then the compressed 1/4 wave action (harmonics) enters into the picture(later in frequency). Thats the upper ripple that so many see at the limits of the horns BW. The 1/4 wave action (upper harmonics) and the horn action combine. And if its designed correctly there will be minimum ripple.
ron

Bob Brines made a statement of fact. He said, "Single-driver full-range speakers have a limited dynamic range." This is true of all speakers, but I think what he meant is that single driver speakers are limited more because of their unique characteristics. It wasn't about a particular implementation, it was about any speaker with a single driver.

By the way, what was used to come up with those SPL figures you quoted? There is a lot of specific information in your post, so I'm sure you must have this information handy. Point source sound falls off at the rate of 20 log d1/d2, so you can see that 108dB at 14 feet is about 120dB/M - pretty strong stuff. Those are prosound levels, amazing from a 4 inch full range speaker.

Seriously though.....I hope like Hell you guys know that was not the point! He did just "verify" the numbers I have claimed from the beginning! Getting Larry to say something "not true" would be like pulling a donkey down the street by his tail! He would not give his "opinion" on the system....he just reported the readings and what he heard.

And yes, Wayne, that was funny to me! You've at least talked with me enough to know for sure that was not the intent of my posting his comments...(he actually typed it all)..I hope everyone else does as well!

Ed

My post was to a specific speaker, not a generalization. The statement "some folks give opinions based on theory instead of experience" is based on 25 years of high end audio interactions. Like anything else, you find armchair experts that have not experienced what they are commenting about. I try to keep an open mind and realise that even if something does not make sense from a theory standpoint it does not make that something untrue. The measurements were taken with a Radio Shack analog spl meter at couch level 14 feet from the speakers. Anything over 100db and I had to plug my hears to protect my hearing. I like listing in the 80's to low 90's tops to all types of musics. Concert level playback is not my normal mode of operation, but if you want it - these speakers can do it with that 7 WPC 300B amp. The room size was approximately 17' by 15' - I did not measure the room so this is an approximation. Let me make something perfectly clear - this post was meant to convey a listening experience with the Horn Shoppe Horn speakers from a 4 hour listening session. It was enough to convince me of the special nature of these speakers. Will they work for everyone? I doubt it. Are they worth a try? Absolutely, if your in the market for some phenominal point source speakers that are open, 3 diminsional, and rather dynamic. It was amazing to me how well they worked at Ed's place with basically no tweaking to positioning and cabling.

Bob

Could you tell us what frequencies you measured the 108 db peaks at, and what the distortion was at the 108 db peaks? When you say the amps sounded a bit strident, are you sure it was not distortion on the part of the driver? It's unreasonable to expect a 4 inch driver to do 108 db bass peaks (say in the 50 HZ region) without significant distortion, in general. So i don't think anyone would fault Ed's design (which I am sure sounds wonderful, and we would all LOVe to hear) if it "only did 102 db peaks in the 50 Hz region". Doing 102 db peaks with a 300B amp (about 8 watts max) leads me to believe the efficiency of the hornshoppe speaker is around 94-95 db. It is reasonable to expect the driver to do undistorted peaks of frequencies above 100 hz upto maybe 105-110 db, depending on the wattage of the driver.

Overall, I don't think Bob Brines & Ed are disagreeing a whole lot. I have actually heard Bob Brines's speakers (almost all his models) and they are very nice. I think they will do 105 db peaks as well, above 100 hz. below that, no, and in fact most single driver systems won't, at least not without increasing distortion.
Again, I reiterate, a single drive comparo between bob brines's speakers (based largely on Martin's designs) and Ed Schilling speakers will be awesome. Based on reviews I have read of Horn Shoppe speakers, they probably sound very good too. It will be a real treat to hear a comparison, and to see the differences between them. Again, ED, PLEASE do ship a pair of speakers for the next GPAF, even if you cannot make it.

-akhilesh

Bob