I believe the current crop of powered professional speakers are all about size and weight.
I remember many decades ago, some friends who had a band lugged around the classic 2 way powered Altec speakers; big horn + 12" or 15" woofer and if I remember correctly, about 60 watts of power each. They were loud with clean sound, but they were big and heavy.
Now with the current high powered plate amps, the speakers can be small and light weight. One person can lift them onto the tripod post stand. They fit in a subcompact car instead of requiring a full size van. They are as loud as the large, old speakers, but in my opinion, the sound quality is terrible.
Yes, but getting accurate TS parameters for compression drivers is difficult, and Hornresp only predicts round horns.
That said, fairly easy to see that depth makes less difference than the flare rate for exponential types or sidewall angle for conical horns.
Thanks! The flare rate on the current crop of horns is rapid, if that makes a difference.
Ed. You're thinking of the Altec A7. That would be no fun to haul around for a band. I don't even move mine out of the listening room! But at work we have subwoofers that weigh 400 lbs each.
Thankfully, they live on casters.
Ed. You're thinking of the Altec A7. That would be no fun to haul around for a band. I don't even move mine out of the listening room! But at work we have subwoofers that weigh 400 lbs each.
Thankfully, they live on casters.
That depends on how well it handles HOMs. As the horn flares out more rapidly there is an increase in the HOMs and they drop in frequency to the point where they can begin to affect the directivity (in my waveguides, for example, the HOMs are so weak that they have no effect on the directivity). I asked once how Hornresp handled this problem but never got an answer.
And if the contour is deliberately sharp then the resulting diffraction would also be very hard to model well. Hornresp, if I understand how its done, would work very well for an OSWG or a slowly flaring device, but a rapid flare and/or large diffraction adds a whole other layer of complexity. Basically the "better" the horn the "better" a simple model is going to be.
The first problem is that you can't use a TS model for a compression driver so the TS parameters don't really apply. But you can get a valid T-matrix, which is more generic than the TS approach. Its also possible to write out a chain of T-matrices of simple form - I've done that before and even my SPEAK program can model a compression driver with this approach. But its still complicated to get the parameters right because you can't access the diaphragm directly. It takes a different approach - which I defined in another thread.
Entire bureaucracys have been set up to install that decoder ring into everyone for eons. No one wants to admit it can't always be installed sometimes its just there. Let's all be comfortable with " abstract instead" Is this coded? (-:
Ok, it seems that I and likely others do not quite follow this.
A highly exaggerated example, for clarity, might be the case where the same compression driver is measured without any horn, and with a high quality suitable horn.
At say 10dB down from the max rating, but near the specified LF xover point, IF we measure the distortion - if you like, mix two freqs for IMD, but keep one where there will be significant excursion - is it being said that there will be an insignificant difference in the measurement for these two conditions?
Will the excursion for the two cases at the lower freqs be similar or very different?
_-_-
Bear
We did this study about a decade ago at B&C. In that test the nonlinearities were not statistically significant in about 25 listeners. Measurement wise the levels were near 20% THD. But the point is that listeners could not detect it. So yes, you can measure it, but you can't hear it. People just do not understand nonlinearities and perception. They somehow think that "Wow 20% THD that's awful!" No its inaudible. Point isn't that nonlinearities are not audible but loudspeaker nonlinearities are very low order. Basically THD and IMD as numbers are meaningless.
We did this study about a decade ago at B&C. In that test the nonlinearities were not statistically significant in about 25 listeners. Measurement wise the levels were near 20% THD. But the point is that listeners could not detect it. So yes, you can measure it, but you can't hear it. People just do not understand nonlinearities and perception. They somehow think that "Wow 20% THD that's awful!" No its inaudible. Point isn't that nonlinearities are not audible but loudspeaker nonlinearities are very low order. Basically THD and IMD as numbers are meaningless.
Many people cannot tell the difference between 16bit/44,1KHz CD quality and MP3 or FLAC. We mau agree there are many plausible reasons for this I have to say that for me distortion numbers sensitivity thing has to be my direct comparison and not heresay. You may well have been convinced, but I may be more sensitive to it. What was the composition of the THD and what frequencies. I presume you had all this. I assume a wide mix of music and speech. How many listeners in the total trial and how were they selected. Were they allowed to hear various types of distortion before making an assessment and so on. What sound levels.
20% THD is considerable.
Quite frankly I can not imagine the situation where 20% THD would not be audible. Well, perhaps if the test situation was set up in such a way that the distortion was masked and made essentially undetectable.
It's pretty easy to hear 20% THD in a tweeter that is off due to a slight misalignment in the gap. The sound of an impure sinewave is rather obvious once it gets beyond a certain %.
I am not an advocate of distortion "numbers" being directly correlative to audibility, so let's not drag out that horse to beat upon. I am aware of your work on the subject and that of D.E.L. Shorter.
I have found it rather trivial to hear the differences between very low distortion HF drivers and let's say "standard" high quality HF drivers. And not merely frequency response differences being at play, nor absolute level differences.
As far as what "people" hear, there's so much stuff that I would consider to be in the general category of "unlistenable" that passes for acceptable or better that I at least have to question just how wide is the range of perceptions and where is the mean exactly?
I suppose if the THD was in the form of "nice" (like a good combination of 2nd, 3rd and not much higher stuff) then it might be quite difficult to hear on many types of common "program" material. But that is not the same as saying it is inaudible.
Signed,
_-_-highly skeptical
Quite frankly I can not imagine the situation where 20% THD would not be audible. Well, perhaps if the test situation was set up in such a way that the distortion was masked and made essentially undetectable.
It's pretty easy to hear 20% THD in a tweeter that is off due to a slight misalignment in the gap. The sound of an impure sinewave is rather obvious once it gets beyond a certain %.
I am not an advocate of distortion "numbers" being directly correlative to audibility, so let's not drag out that horse to beat upon. I am aware of your work on the subject and that of D.E.L. Shorter.
I have found it rather trivial to hear the differences between very low distortion HF drivers and let's say "standard" high quality HF drivers. And not merely frequency response differences being at play, nor absolute level differences.
As far as what "people" hear, there's so much stuff that I would consider to be in the general category of "unlistenable" that passes for acceptable or better that I at least have to question just how wide is the range of perceptions and where is the mean exactly?
I suppose if the THD was in the form of "nice" (like a good combination of 2nd, 3rd and not much higher stuff) then it might be quite difficult to hear on many types of common "program" material. But that is not the same as saying it is inaudible.
Signed,
_-_-highly skeptical
Let's see now, (and I'm going to try to make this Forrrest Gump clear)
We can't easily hear up to 20% THD and IM distortion, which is simple to measure, but this other distortion (which we have named "HOMs") is difficult to measure, does not readily show up as THD or FR irregularities, yet is audible enough that we should trade vastly decreased driver excursion (which simple physics dictates *will* radically increase measurable THD etc) to eradicate it?
Got it. Having a hard time with it, greatly appreciate your study, wish thee were much larger ones including audio pros as well.
We can't easily hear up to 20% THD and IM distortion, which is simple to measure, but this other distortion (which we have named "HOMs") is difficult to measure, does not readily show up as THD or FR irregularities, yet is audible enough that we should trade vastly decreased driver excursion (which simple physics dictates *will* radically increase measurable THD etc) to eradicate it?
Got it. Having a hard time with it, greatly appreciate your study, wish thee were much larger ones including audio pros as well.
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How in the hell did those guys get it all so damned right with speakers nearly a century ago? My premise in this thread is now ridiculous to me, but verifying the true genious of those people really is priceless. Smaller, cheaper, more forgiving but not really better. Amazing.u
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I can save you a lot of time.
If your room is not the size and dimension (approximately) of a small barn (literally) you are sunk, there is nothing you can do to a smaller space that will be equivalent, nor as good.
_-_-
Well they did IF and to the extent that you happen to be situated in one of those aforementioned barn sized spaces (aka a theater)!
Putting full size horns into your average size living room is not really a viable approach. Also they were unable to conquer the time delay between the ranges of horns. But even if you accept this point, in reality these early designs were not perfect at all. However the 555 driver is very good, if you understand what it does and does not do well.
Assuming you are referring to WE Theater horns, or perhaps Klangfilm?
_-_-bear
Funny but true. I now can save my people from playing "The Speaker Game" since I see plainly that once you get it, you understand it is not very nice to play. Individual room acoustics in real depth is a worthy goal I think. People are stuck with theur spaces.
Bear, respectfully disagree about theater size rooms. My room is 16x30. Zero cohesion issues with "DSPed" Peavey Sp1, (think Lascala with EV/Keele style CD horn). pretty good sized horns. These speakers walk all over all of my ref monitors, and I know with the right driver they could be better still. I stand by the compression driver horn combo as having the least compromise for most of us. I think a 2 way such as Geddes, QSC K12, Etc would close the gap in smaller rooms too. I can't see using direct radiation tweeters again once I have this down. And if Danleys speakers work, then it is all over, but here I am playing "the speaker game" when I know better. (-:
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