I'm not sure if I get you right. But better is to minimize reflection as any reflection/diffraction must be accounted for in the design (and many skip that). A "pyramid" shape (like OP's new speaker) has better chance for good imaging. The tweeter panel MUST not vibrate during reproduction, so the narrow panel also help with this. When the tweeter is on the same (large) panel with woofer, special reinforcement must be done with the tweeter panel part.
Some people think that "pyramiding" is not effective because the troubles to create the enclosure and the often not so artistic look do not worth the "small" improvement when the reflection is really accounted for in the design.
Under or over damped is a simple mater of measuring the Q. It can't be done visually. My experience would not blame a flimsy box with poor imaging, but crossover and driver design. Muddy, ill-defined bass yes. Imaging, no.
Steve, I would have to take exception to just about all your observations. You are just guessing. There are quite a few speakers out there designed for flush mount. Quite popular in home theater. Most mini-monitors are designed to be away from boundaries as you can get better imaging. One has to play with the speakers in the room to see what works. As an example, I had Ditton 44's for years. If standing on flat stands, imaging was fair. Sitting on the floor tilted back about 10 degrees, imaging was very good. ( I did have a modification to deal with the raised edges )
I build my subs to take advantage of two surface boost. I have no idea where your "most modern" statement comes from except cheap subs or boom-boxes. I find most modern mid-price and up speakers to be surprisingly well balanced; over bright if anything. Your "large speaker in small room" makes no sense to me at all. True, you are not going to set up a pair of Maggies in a 10 x 12 foot bedroom very easily and Klein horns would kind of take up the room. I can get very clean 30Hz bass in small rooms with very little effort. If you want very loud movie effects, then you need to build bass traps into the walls or ceiling. This is DIY after all.
I go back to the room. I built a pair of inexpensive (DatonRS/Vifa) monitors to sit, yes, right against the wall. Top notch cabinet, fair crossover. Imaging was very poor. I placed a 4 x 5 foot absorber I built behind each one. What a surprise when the soundstage was larger than the room and I even get small 3D effects. Serious, almost like surround sound, but this is only two speakers. I was expecting to to be better, but not vastly better. So much so, I have not bothered to replace them yet.
In other words, don't blame the speaker first. Yes, modern speakers can be vastly better than some old ones. Imaging is a system problem. Take a systems approach.
Steve, I would have to take exception to just about all your observations. You are just guessing. There are quite a few speakers out there designed for flush mount. Quite popular in home theater. Most mini-monitors are designed to be away from boundaries as you can get better imaging. One has to play with the speakers in the room to see what works. As an example, I had Ditton 44's for years. If standing on flat stands, imaging was fair. Sitting on the floor tilted back about 10 degrees, imaging was very good. ( I did have a modification to deal with the raised edges )
I build my subs to take advantage of two surface boost. I have no idea where your "most modern" statement comes from except cheap subs or boom-boxes. I find most modern mid-price and up speakers to be surprisingly well balanced; over bright if anything. Your "large speaker in small room" makes no sense to me at all. True, you are not going to set up a pair of Maggies in a 10 x 12 foot bedroom very easily and Klein horns would kind of take up the room. I can get very clean 30Hz bass in small rooms with very little effort. If you want very loud movie effects, then you need to build bass traps into the walls or ceiling. This is DIY after all.
I go back to the room. I built a pair of inexpensive (DatonRS/Vifa) monitors to sit, yes, right against the wall. Top notch cabinet, fair crossover. Imaging was very poor. I placed a 4 x 5 foot absorber I built behind each one. What a surprise when the soundstage was larger than the room and I even get small 3D effects. Serious, almost like surround sound, but this is only two speakers. I was expecting to to be better, but not vastly better. So much so, I have not bothered to replace them yet.
In other words, don't blame the speaker first. Yes, modern speakers can be vastly better than some old ones. Imaging is a system problem. Take a systems approach.
A flimsy box will make a proper design harder. Especially in a 2-way floorstander with large woofer, we have too many issues to solve (and often we have to sacrifice something). It will be easier for example if the tweeter is close to one side than in the center of the panel.
I have mentioned 2 factors affecting good image:
1) There should be no non-signal sound coming from speaker (cone, mechanic, enclosure, port, etc)
2) The intended sound must come to ears completely and timely. This is why positioning etc affect "stereo" imaging.
Point #2 can be worked around, but point #1 is NOT.
Many ways to skin a cat, of course. But the two best imaging systems I've ever heard were both bookshelf designs. One was a simple Goodmans two-way closed box built flush into a library wall in a well damped room. The other was the mini-monitor BBC LS3/5A mounted up on the wall.
Steen Duelund explains:
Phase is easy enough to get near-perfect with established BBC/KEF R101 techniques. Here's one I simmed using paper bass and tweeter:
Is there anything hard about speakers? Not really. 😀
Steen Duelund explains:
An externally hosted image should be here but it was not working when we last tested it.
Phase is easy enough to get near-perfect with established BBC/KEF R101 techniques. Here's one I simmed using paper bass and tweeter:
An externally hosted image should be here but it was not working when we last tested it.
Is there anything hard about speakers? Not really. 😀
@ Jay, I believe that jitter's speakers image well and sound good, but I disagree on why.
My first point would be that reinforcing the tweeter panel is a matter of construction. On a larger panel we may need to try harder... so we do.
Regarding the 'reflections', a baffle is really just a wide waveguide. A sound wave will radiate outward like a dome and continue to do so while the baffle is there. It is untroubled because it is not changing it's shape or direction. Untill it reaches the edge, of course.
These problems can all be treated on various baffles but assuming no treatment, the more sound that radiates around the baffle, the more diffraction and the more reflections (from the walls etc behind the speakers).
Which promotes spaciousness, and can be a good thing.
But on the other end of the scale with more and more directed sound the room is systematically toned down and it tends to approach the cleanness of headphones. The spaciousness is reduced.
I don't know if I've heard the official definition of imaging, but I think it means the successful reconstruction of the intended space protrayed in the recording. Headphones can image. The spaciousness is a bonus, if done well, or a hindrance if not.
My first point would be that reinforcing the tweeter panel is a matter of construction. On a larger panel we may need to try harder... so we do.
Regarding the 'reflections', a baffle is really just a wide waveguide. A sound wave will radiate outward like a dome and continue to do so while the baffle is there. It is untroubled because it is not changing it's shape or direction. Untill it reaches the edge, of course.
These problems can all be treated on various baffles but assuming no treatment, the more sound that radiates around the baffle, the more diffraction and the more reflections (from the walls etc behind the speakers).
Which promotes spaciousness, and can be a good thing.
But on the other end of the scale with more and more directed sound the room is systematically toned down and it tends to approach the cleanness of headphones. The spaciousness is reduced.
I don't know if I've heard the official definition of imaging, but I think it means the successful reconstruction of the intended space protrayed in the recording. Headphones can image. The spaciousness is a bonus, if done well, or a hindrance if not.
Hi Steve. The traditional view doesn't account for the limited mode coupling of 2π radiation below the schroeder frequency AFAIK, which of course could benefit from some subs or it may be lumpy.
What about when you walk to the rear of your speakers, trip over your soldering station and have a cranial rear wall reflection?
I don't know what jitter's tweeter is but I cannot see where we have disagreement.
Of course I understand these theories regarding reflection/diffraction and so on, but I put higher value on the "pure" imaging (point #1 in my previous post) so it might look to you as if I disregarded the issue you raised.
Some here might find difference in the quality of imaging from active and passive crossover. This better image is related to factor #1. Good speaker will image well even in mono. The sound will float. The tweeter and woofer will blend. You cannot see the woofer and especially the tweeter. This is not 100% electronics but mechanics included.
What about when you walk to the rear of your speakers, trip over your soldering station and have a cranial rear wall reflection?
If you can achieve factor #1 well, i.e. your speaker images well in mono, your speaker will sound good from anywhere.
These days I regard the room as a speaker cabinet too. It needs damping and has a fundamental resonance just like the speaker. Interestingly, the professionals use proper inset boxes, as well as nearfield monitors (Yamaha. isn't it?) to simulate the sort of bright and boomy rubbish most of us have at home:
This picture of Aretha Franklin "'AVING A FAG!" between takes of "Say a little prayer" which I found on my image search made me laugh for some reason. 😀
'Spect she likes a slug of whisky too.
An externally hosted image should be here but it was not working when we last tested it.
This picture of Aretha Franklin "'AVING A FAG!" between takes of "Say a little prayer" which I found on my image search made me laugh for some reason. 😀
An externally hosted image should be here but it was not working when we last tested it.
'Spect she likes a slug of whisky too.
Resonances may or may not be significant. They amount to a build up and decay, over time, of something that is part of the signal, but they will sometimes amount to sounding nothing more than an increase in response, but other times... 😉
Still a cabinet should be solid, but there is a limit to how far you need to go, which can be measured.
By the way, to answer your question I began disagreeing with you on your assessment of wider baffles.
The tweeters in my new speakers are Scan Speak R3004/602010.
I must say that these do a very good job but I was wondering if the grille protecting the cone doesn't get in the way of even better imaging...
Those in the old speakers are from ATL themselves according to the sticker on the magnet (see the pictures in this thread on a German forum). But a search on the woofer's type (M17W07) leads to a Vifa unit, so I doubt ATL actually made their own tweeters, but who knows?
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I think what Jay means is that the sound should come from the middle, as if there were only one speaker.
First, the drivers must not produce mechanical sound of their own. Paper cone is the best candidate for possible low distortion. Crossover must not put the drivers under stress (you cannot see it from simulation). The signal from 2 drivers in crossover frequency must be perfectly in phase.
Of course, mono image is different with stereo image (this is I believe is your concern). But mono image ensures best stereo image, without sweet spot. And mono image is not just about image itself but about low distortion non fatiguing speaker. Its the only way you can feel the singer standing in the room, not that kind of headphone image.
The only way a crossover will help, or effect the problem is if you are using one to keep the speaker from vibrating at the box at it's resonance.
If the box's resonance is within the audio band of the speaker, then the box must be built rigidly to resist vibrating.
As I mentioned earlier, if you look at your old speakers, they have a fairly large thin baffle with a speaker vibrating in the middle of it. That is just like an acoustic guitar with the strings mounted to a "bridge" in the middle if a thin baffle.
The box will create local noise, just like tapping on it. with your knuckle.
As another poster mentioned the tweeter is effected by this moving baffle.
I did not notice if the drivers were the same size, but it would be interesting to switch them to verify if it's the box or the driver having the biggest impact. You could cut a doughnut adapter to fit the new speaker to the old cabinet.
If the box's resonance is within the audio band of the speaker, then the box must be built rigidly to resist vibrating.
As I mentioned earlier, if you look at your old speakers, they have a fairly large thin baffle with a speaker vibrating in the middle of it. That is just like an acoustic guitar with the strings mounted to a "bridge" in the middle if a thin baffle.
The box will create local noise, just like tapping on it. with your knuckle.
As another poster mentioned the tweeter is effected by this moving baffle.
I did not notice if the drivers were the same size, but it would be interesting to switch them to verify if it's the box or the driver having the biggest impact. You could cut a doughnut adapter to fit the new speaker to the old cabinet.
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I don't think I have assessed any baffles. I have read enough that I don't need to invent my own assessment. Baffle theory is the basic in understanding speaker design. What I am trying to point out is my "discovery", not theory that we all have read. "Discovery" is not the theory but how to relate theory with perception.
No, the crossover is crucial with boomy bass. In practise you can reduce the size of the bass coil and increase the bass capacitor accordingly. Coils are not hard to unwind and reduce. People buy boom and bright treble, but then weary of it. 😎
You can then place the speakers closer to the wall. Placing the reflex port somewhere else might help, or you plug it altogether since they tend to boom too. Even cut the box down to about a third size since reflex Qts =0.38 usually works out that way, and make it closed box. All good fun, all very DIY.
The devil's in the details. Bracing is best done with the same material for less colouration, so that means chipboard here. I see some rather hopeless non-polar capacitors in there too. 😀
You can then place the speakers closer to the wall. Placing the reflex port somewhere else might help, or you plug it altogether since they tend to boom too. Even cut the box down to about a third size since reflex Qts =0.38 usually works out that way, and make it closed box. All good fun, all very DIY.
The devil's in the details. Bracing is best done with the same material for less colouration, so that means chipboard here. I see some rather hopeless non-polar capacitors in there too. 😀
What do the tweeters look like? How low do the tweeters go?
BTW, that foam damping is near the driver and it's on a wall surface (which is worse). That portion of the cabinet also looks "cramped" for space (..even if it does expand into the lower portion of the cabinet).
Paper cones self-damp their resonances (under break-up) better than most, but, for a truly high-fidelity set-up, the speakers should not be operated under those conditions: they're another set of resonances that you don't want.
So long as the cone is operating as a piston, the distortion's in the motor and suspension. The cone material has nothing to do with it.
I still don't understand how you can have any image from only one speaker. IMO, a stereo image is where you can say or point to where all the instruments are. With only one speaker, they're all coming from the same place, so there's no stereo image to it.
Chris
Jay is saying if a pair of speakers can't even image a centre properly, say due to phase anomolies, there is no hope for the rest of the imaging. He is right.
Paper cones break up pretty badly, but have more self damping than kevlar, glass fibre and aluminium. Polypropylene is possibly the most overdamped material.
You can see some huge resonances in these (rather well phase matched) paper cones around 5kHz and 14kHz, but in fact breakup starts around 750 Hz!
Piston-like respionse in speakers is a wrong design target. You hope for a gaussian response where the centre moves more than the edges. Otherwise you will get huge diffraction effects in the far field. The same goes for crossovers. You want smooth curves, not step-like ones:
Hope that clears that up. There is so much WRONG thinking in this branch of engineering. Life is too short to be muddled in the head. 😀
Paper cones break up pretty badly, but have more self damping than kevlar, glass fibre and aluminium. Polypropylene is possibly the most overdamped material.
You can see some huge resonances in these (rather well phase matched) paper cones around 5kHz and 14kHz, but in fact breakup starts around 750 Hz!
An externally hosted image should be here but it was not working when we last tested it.
Piston-like respionse in speakers is a wrong design target. You hope for a gaussian response where the centre moves more than the edges. Otherwise you will get huge diffraction effects in the far field. The same goes for crossovers. You want smooth curves, not step-like ones:
An externally hosted image should be here but it was not working when we last tested it.
Hope that clears that up. There is so much WRONG thinking in this branch of engineering. Life is too short to be muddled in the head. 😀
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