I ordered a thruster overnight from Amazon, so I replaced the underperforming unit and sure enough, problem solved, all 4 speakers sound good, so the first test with all 4. I have a little dayton 30w driving one set and Fosi "100w" driving the other, I'll probably buy another Fosi over the weekend just to have something and then think more about amps.
It's definitely the wall of sound I was hoping for. I'm going to be doing a hell of a lot of relaxing over the weekend and listening.
I have an idea for a simple wall mount, maybe will even finish it this weekend. But the wall is secondary now after having listened from my recliner. The only bad thing about them is they block the view of the tv.
Maybe will work on getting my recording set up for a sample.
It's definitely the wall of sound I was hoping for. I'm going to be doing a hell of a lot of relaxing over the weekend and listening.
I have an idea for a simple wall mount, maybe will even finish it this weekend. But the wall is secondary now after having listened from my recliner. The only bad thing about them is they block the view of the tv.
Maybe will work on getting my recording set up for a sample.
Attachments
If one understands the phrase "IN PRINCIPLE" then that's EXACTLY the point!
(see, we can all do emoticons. Impressive eh? 🤦♂️)You measure the straightness of a row of bricks with a calibrated spirit level and a plumb line, not with your eyes.
You measure the accuracy of TV system colour with calibrated sensors and spectrophotometers, not with your eyes.
You measure the trueness of an audio reproduction system with a calibrated microphone and response graphs, not with your ears.
Anybody who says they can judge the accuracy of any physical system by eyes or ears alone is hopelessly over-estimating their abilities.
Obviously there will always be those who prefer things like, for example, KFC and MacDonald's to real food; and there will always be those who prefer a skew line of bricks to well-built architecture; and there will be those who prefer the sound of a cheap boom box to a concert-quality sound system. Unfortunately one cannot argue against such personal, subjective preferences.
This is why we have calibrated measuring systems.
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Again how does measuring sound tell you if it sounds good? Only your ears can tell you that as its subjective.
Again how does measuring the TV tell you if the picture is better then another? Only with your eyes can tell you that as its subjective.
Anyone that says they can judge how a speaker sounds or the quality of a picture by measurements is an idiot. Nobody buys audio gear without listening to them , the same goes for a TV. Its like asking Stevie Wonder which TV has the better picture quality.
Food is no different as you cant tell how a food taste UNLESS you actually taste it as no amount of measurements can tell you other wise as its once again subjective. This is why we have 5 senses.
Calibrated measurements are to measure thats it , it wont tell you how GOOD or BAD it sounds, looks or tastes. You have to be a special person to think otherwise. Hows that for usage of emoticons, impressed?
Only your ears can tell you that as its subjective.Again how does measuring the TV tell you if the picture is better then another?
Only with your eyes can tell you that as its subjective. Anyone that says they can judge how a speaker sounds or the quality of a picture by measurements is an idiot.
Nobody buys audio gear without listening to them , the same goes for a TV. Its like asking Stevie Wonder which TV has the better picture quality.Food is no different as you cant tell how a food taste UNLESS you actually taste it as no amount of measurements can tell you other wise as its once again subjective. This is why we have 5 senses.
Calibrated measurements are to measure thats it , it wont tell you how GOOD or BAD it sounds, looks or tastes. You have to be a special person to think otherwise.
Hows that for usage of emoticons, impressed?
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A classic trick as a sound engineer when you run out of aux channels on the mixer to give each musician the mix they want, is to make use of how easily one can fool our ears. Say the bass player wants more drums, but is on the same aux as another musician who you just turned down the drums for.
The easy solution is to just pretend turning up the drums for the bass player until he says they are loud enough. Works every time
We don't hear with our ears, we hear with our brain, and what we think we hear is extremely susceptible to suggestion and preconceptions. So it is just a fact that non-blind listening tests are nearly useless, and all manufacturers of audio equipment and software has to be aware of that to not waste time chasing ghosts.
The easy solution is to just pretend turning up the drums for the bass player until he says they are loud enough. Works every time
We don't hear with our ears, we hear with our brain, and what we think we hear is extremely susceptible to suggestion and preconceptions. So it is just a fact that non-blind listening tests are nearly useless, and all manufacturers of audio equipment and software has to be aware of that to not waste time chasing ghosts.
This does indeed work every time! Two of the many tricks I've learned from being a stage performer as well as a live-sound engineer...
1. When you're on stage asking for the monitor mix to be adjusted, then you close your eyes and listen for the difference. hehehe... it buggers up the sound engineers most of the time.
2. When working at the desk, mixing live or for recording, then again, close your eyes and mix by ear, not by sight. I've had to teach many youngsters this trick many times. Once your eyes are out of the "mix" so to speak, then ears become paramount. I'm sure this is why double-blind listening tests are so important for sound systems.
The elephant in the room as far as system quality is concerned is, of course, that one cannot hope for a decent sounding system if it has a ragged frequency response. This is pretty obvious. But arrogant amateurs will usually insist that their untrained perceptions are all that matter when auditioning systems. The preceding comments are all the proof you need. This is why one can go to almost any hi-fi shop populated by such buyers and, as long as something LOOKS good and costs a lot of money, then they think it apparently sounds good too. This is also why clever marketers will compress the dB resolution to 10db/division on the y-axis, and apply 1/3rd-octave smoothing to the reading, and then display this as an "acceptably flat" response. Why display such info? Because some of those buyers have heard something about it somewhere in a hi-fi magazine, and they believe that they look intelligent when discussing it. The eyes, of the pimply youth with the fat wallet in the sales room, will lead the ears and will follow the red herring no matter how crappy the system is that he's listening to.
Working in high-end hi-fi shops in MY youth I've seen this happen sooo many times.
Well, as long as there are gullible buyers out there who believe that their limited perceptions will actually differentiate better than a professional measuring system will, then manufacturers will happily take their money away from them.
So what does happen if you measure a frequency response using a mic very close to the panel, and move the mic across the surface of the panel? With one exciter? With two? Easy enough to see....
The attached videos show exactly that. In all three videos, the panel is a 4 mm thick, 0.36x1.2 meter plywood panel, mounted to a wood frame with Poron foam around nearly the entire perimeter.
The first video is with a single exciter, mounted about 15 cm left of dead center. Second is with an additional exciter mounted 5 cm closer to the center than the first. And third with the second exciter moved to 5 cm right of dead center.
Using REW I played pink noise and used the RTA feature in spectrum mode to monitor the frequency response. I started with the mic near the far left edge, and moved the mic slowly across the full 1.2 m width of the panel. I kept the mic along the center of the 0.36m dimension of the panel and about 3 mm from the panel face during the entire test. I took about 3 minutes for the entire traverse of the panel, but recorded the video in time lapse mode, so each video is only about 12 to 15 seconds long.
For the RTA I used a short FFT (128k) to avoid too much smearing of the data, with 1/48 smoothing and 4 averages. This gave pretty good results, especially for frequencies between about 100 and 1000 Hz. At lower frequecies the FFT has poor reslution, and at high frequencies the panel's natural frequencies are too close together to be distinguished, but the results between 100 and 1000 Hz show pretty clearly what is actually happening.
Here's the video with a single exciter.
If you examine the video closely, it shows exactly the response we should expect from modal panel. The response at each instant reflects how near the mic is at that moment to each of the antinodes of the natural frequencies. Hence the response at any natural frequency will be at it's maximum response as many times during the video as there are antinodes for that mode.
For example, the 1,4 mode, with a natural frequency of about 150 Hz, peaks exactly four times, because there are four antinodes across the panel for that mode. Likewise, the 1,12 mode (880 Hz) has 12 antinodes across the panel, and peaks 12 times during the video.
The in-between modes are at
202 (1,5)
261 (1,6)
336 (1,7)
422 (1,8)
519 (1,9)
626 (1,10)
750 (1,11).
And each of these frequencies will have a peak in their response exactly as many times as there are antinodes of that frequency.
Also it's worth noting that the frequency peaks don't actually move. For example, if you look at the response at say, 300 Hz, which is about halfway between the 1,6 and 1,7 modes, you will see that there is never a peak there, rather, only peaks on either side that move up and down.
Now here is the video with 2 exciters, close together. You can see that while there are some differences, they are basically the same. The peaks are at the same frequencies, and they all act in bacially the same way regardless of whether there is one exciter or two.
And here, with the exciters spread farther apart. You will see my hand waving across the screen as the mic passes over each of the exciters. As far as I can tell there is nothing particularly different happening when the mic is between the two exciters, but judge for yourself.
Eric
Thanks Steve.
All three should be public now.
All go up to only 5 Kz. I think the 100 to 1 kz region shows you what's going on. Above that the natural frequencies get too close together to be distinguished by the measurements. But my best guess is that the same basic thing is happening there.
Eric
All three should be public now.
All go up to only 5 Kz. I think the 100 to 1 kz region shows you what's going on. Above that the natural frequencies get too close together to be distinguished by the measurements. But my best guess is that the same basic thing is happening there.
Eric
Thats the problem most people here aren't building much. They build one or two pairs of panels and thats it.
Speaking of which I am in the process of prepping some new EPS diaphragms for my next DML project.
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According to some people you cant tell how good something sounds with your own ears you need to do measurements to convince yourself of what you are hearing.
This is brilliant, and perfectly proves the fact that, unless one still insists on misunderstand the modal principles involved, there's no such thing as "combing" between multiple exciters on DML panels.