Right 🙄.....gotta remember the fast driver/ fast magnet thing..........
Don't get addicted to drinking.
343m/s x 0.000 046 s = ~0.016m - MY BAD, lost zero in calculations...
On the 2500-2800Hz, which may be suitable crossover freq, the difference - I guess is less
Vituixcad simulation shows around ~2.5cm for perfect match on ~3400Hz . This is physical build of speaker + electrical(electromechanical?) difference, as speaker and mic is not moved between measurements, and I have no idea where are exact acoustic centers of speakers as they are built in and if I take tweeter apart, I still have no idea where center is.
Probably there you will find more about this... http://www.troelsgravesen.dk/stepped-baffle.htm
Yes, most likely the better way is to tilt your speaker back (it has to be built to be listened in that way) or build stepped baffle - again, it has to be built from ground up for this.
Not trying to be too picky here but not one component or element of the original 604 can be found on the 604 8K, that you show. The only thing that didn't change was the concept.
Nope. I had in mind that tweeter is "faster" to produce sound from electric impulse than woofer. That's it. It is more or less the same as making Z offset (positive) to it.
If you can hear it and how much you can hear it at which frequency - that is another question.
Do you mean it reacts faster, or do you mean it's closer and arrives sooner.. or perhaps you mean the impulse is more compact and reaches a peak earlier.
I suggest that all these things can be shown in a plot of response/phase so that we don't need to know the details when doing our electrical manipulations.
Yup. I worked in automotive aftermarket for a long time, and every coax/triax had a phase problem between woofer and tweeter(s).* You couldn't fix it with the simple 1-capacitor crossover often dictated by cost.
*Triaxials do NOT have a "midrange." They have a tweeter, and a tinier tweeter...which is sometimes just a little silver piezo button doing nothing much.
It may be both. Cone mass is definitely variable. You can expect tweeter cone with mass of 0,5g to arrive at peak MUCH faster than midwoofer with 10-20g. Physics confirms that. But here is the variable of magnet strength too. It is a drag race between a sportsbike and LeMans series car - have no idea at which conditions who wins. Simple logic from indirect measurements show that tweeter is faster.
Personally I would like to see this measured at the same freq of the crossover, like 3000Hz, at the same mic distance from voice coil center. You need to take apart driver to see where exactly coil center is. I have lots mid range-fullrange of the driver pairs to commit to this experiment, need just some cheap tweeters. But still have no idea how to setup REW of other program to do that at single freq.
So if both drivers produced a continuous 3000Hz, what would be the difference between them at -say- 2 meter distance from both acoustic centers?
Distance???? If 2 or more drivers are coax - distance is the same at 1m, 2m or whatever. We are non-English speakers, perhaps you had in mind another word? In non-coax drivers placed on baffle you can count with Pythagoras theorem yourself, but if you move a small amount of Z distance one of the drivers, lets say 20mm, what is 1% of distance - sound will change. You can simulate this in any program of your choice. And the change is substantial
What I wanted to say, that we need to measure 2 different drivers, with very different Mms, lets say tweeter and woofer at the same mic distance from the moving cone at the same freq, the crossover frequency being the most important. Simple simulations show 16-25mm difference for coax. As I haven't taken apart coax and cannot say if tweeter and woofer voice coils are aligned center-center.
You could measure that with dual channel standard equipment. Lot of us here do when designing systems.
Well I tried to do this for some limited range (lets say 2950-3050Hz), but got nonsensical results. Yes, I have 2 channel interface. Yes, it works well with full sweep.
Perhaps someone can write gating, IR windows and other parameters so we can all recreate?
If we eliminate this making sweep in only crossover region - the conditions are the same for both.
EDIT: if someone posts results here and all the REW file somewhere, we will all see what is exact difference in "speed". My prediction is that this is in the 0.04ms range, because when we measure tweeter and woofer - we do it with full sweep, in my case 5Hz - 48kHz
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Am I correct when I assume you’re searching for the so-called acoustic center of a driver? Well, that can be somewhere between the back end of the voice coil (not so likely) and the suspension roll of the cone or top of the dome (also not that likely).
It varies with frequency btw. Speed of sound in the applied materials of the cone/dome assembly and the geometry are dominant factors. I’m not sure what your point is or what it is you are after. These things can almost always be solved by using the right and tailor-made crossover.
It varies with frequency btw. Speed of sound in the applied materials of the cone/dome assembly and the geometry are dominant factors. I’m not sure what your point is or what it is you are after. These things can almost always be solved by using the right and tailor-made crossover.
Ok, lets take aluminum 19-25mm tweeter and aluminum 3-4' midrange. Frequency, where both of them are working in pistonic mode, not breaking up or entering any of the "weird" modes, like 2500Hz in this case. Speaker works in this principle: wire in magnetic (electric? electromagnetic?) field is wrapped on the hard surface, which is the part of the cone (cone itself, but hidden from outside view) which has rigid "connection" to the outside cone part. As it is from aluminum, it is pretty rigid and the speed of sound, which is also the speed of mechanic impulse, in aluminum depending on the conditions, shapes and so on should be around 6000m/s, which is non-factor here, so we can assume, that the search for acoustic center is not required, we need just to put mic to the exactly the same distance from the cone of each speaker. 5mm can be reasonable distance. Then measuring setup should be to see the delay to the impulse peak and also till impulse "start" or bottom. I am non-english speaker, so it is hard to express a little scientific things.
There is no need to search for acoustic center.
Are there logic mistakes?
Then I have no clue what it is you are looking for. Speed of sound = speed of sound, whether tweeter or woofer. Higher acceleration of cones/domes = higher frequency reproduction and/or higher level (it’s the same in fact). Nothing more, nothing less. There is no such thing as speedier loudspeaker units in any other sense.
Do not agree on this one. Some subwoofer drivers also can play 2-3kHz, sound will be anything but listenable, but I cannot agree that they are "fast" at that freq.
Don't put everything into one: mechanical impulse travel speed is speed of sound IN the material. Aluminum is not air. Speed of impulse is different. But this is not the case.
We need measurements to finish all the discussions about "fast/slow" drivers. My bet is that first impulse peak is faster on the typical tweeter than the woofer.
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