Too Tall: Hi Tom, what is your opinion/understanding on progressive windowed analyzers that let more reflections in as you go down in frequency?

Tom: I suppose it would depend on what one was trying to do. If finding the transfer function of the speaker itself was the goal then having the reflections is not a good thing. Even the TEF machine will let in some corrupting information if you are not in a large enough space or outside.

Hellsgate: Hi Tom. What are your current opinions of the (EAW) KF940, it's spec' and performance, vs. the BT7. John Halliburton and I have been having some discussion over at AAPLS, and it seems to be a lot of marketing fluff/bashing, rather than mathematics and facts.

Tom: I can say that all of the specifications for the BassTech 7 are repeatable measurements that have been verified by independent labs. I have not on the other hand, had a chance to measure any 940s myself and can't speak of them from a position of first-hand knowledge.

Too Tall: I know gated is better for speaker design. I was just wondering what failings it might have if you used it for looking at room interaction.

Tom: Well, room acoustic measurements are more of a Syn-Aud-Con kind of thing - and to be honest I don't remember any details about the differences in measuring in that application.

Steve Gray: What happens to a sound wave as a horn's circumference begins to exceed a frequency circumference of the wave?

Tom: The critical distance you refer to is the point in the horn where the acoustic transformation is pretty much over. On the other hand, the horn past that point can still control the directivity of the radiation pattern.

Steve Gray: Are there reflections and/or cancellations?

Tom: If the horn has reached that dimension, it should be pretty much free of any cancellations or reflections. However, at the mouth of the horn there is a sharp dis-continuity, which does radiate some energy- the only cure is making the mouth larger.

Charlie Hughes: If the directivity is being controlled, isn't the driver still being loaded? And if so, isn't the horn still operating as an acoustic transformer?

Tom: In terms of looking at the radiation resistance on the driver impedance - I believe that part is pretty much over at the critical distance and beyond, while there is no doubt that part of the horn governs directivity and contributes to the overall on axis SPL.

Weogo: I used td-1s as monitors recently. Band was impressed with how clear they are.

Tom: Yes, actually that was what prompted the development of the SPL-trik monitor. I had a pair of td-1s at the house, and I measured them laying on the floor and thought HEY - this is cool. It is the same boundary compliance that lets them operate on a physical boundary, like the floor, as well as an acoustic boundary, like the acoustic mirror of an adjacent speaker.

chmed: Do you plan to release a studio version of the td-1?

Tom: The closest thing right now is called the C3, which is not boundary compliant, and is made for use where one speaker per location is appropriate. They do sound like all the other Unity horn systems.

Grampa: Have you looked at the Nexo Geo waveguide and what do you think?

Tom: I have seen drawings of it. It seems like a clever idea and is a good example of altering the curvature of the exiting wave in a way that makes it more compatible for arraying. Again, I have not actually measured one but the picture looks cool.

Too Tall: Any chance the full-range speaker you designed that used the two swinging doors might come back from the dead?

Tom: We are probably within a year or so of materials and manufacturing technology allowing us to build them (we're a small company, ya know). I always liked that line source driver and haven't forgotten about it.

Too Tall: Did they end up with a lens to widen hi frequency?

Tom: They use a reflector to make the effective origin further away than the driver position would normally allow it to be.

JimG: How much further do you think the technology can go in regards to low end, as in going lower and being able to handle loads of power as well as a reasonable size package?

Tom: The wall of science does dictate a maximum efficiency given the box and low cut off. That will always be a problem. On the other hand, there is no doubt that one's hearing extends further than the 40 or 50 hertz that most music systems can go down to.
Traditionally, manufacturers have told people how low they need to go based on the technology they were selling. Personally, I think eventually sound systems will cover the entire audible spectrum.

Steve Gray: From me, and I'm sure other LAB readers thanks for your objective information sharing, and scientific "spirit".

jack arnott: I was wondering about odd number of speakers, because is seems that one speaker needs the other speakers "pressure" to exit smoothly. Is this true, or could you have one speaker attached to the side of a horn?

Tom: I did make several horns with only two mid drivers - they did not work quite as well (frequency response) as the ones with four, but I'm not sure that one couldn't make one that was acceptable with two or three. There are some details where the sound comes in that need to be addressed.

JR: Hi Tom: Have you ever played with exotic box materials, like the carbon fiber Sound Image boxes?

Tom: I have drooled over the boxes - but us doing that right now is bit out of our reach.

Grampa: Well, if you patched things up with QSC, I understand their reps smoked your Threshold amp, maybe you could work something out ;-) You have expressed doubts about their new powered carbon fiber sub.

Tom: No, I don't have any doubt about QSC - they're a good company. On the other hand, if you take something the size of a 4-inch voice coil and put 1500 real watts into it - it ought to be bright enough to read by after a short period of time.

Grampa: Which is why Meyer's processor limits the voltage sent to their subs.

Tom: That sounds like a good idea

Charlie Hughes: Have you been involved in any hi-fi (home) projects?

Tom: Yes, I would like to think that our business is a blend of hi-fi and concert sound. Certainly hi-fi was my interest for many years.