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thought joe might get a little blood flow in his groin from knowing that we have a company in-house today that is showing us a system that transmits SDI wirelessly with almost no latency or quality loss.
oh boy! |
Along the same lines one of my favorites Audioholics Home Theater Forums - View Single Post - Speakers; When is good enough, enough
We gathered up a 5 of our audio buddies. We took my "old" Martin Logan SL-3 (not a bad speaker for accurate noise making) and hooked them up with Monster 1000 speaker cables (decent cables according to the audio press). We also rigged up 14 gauge, oxygen free Belden stranded copper wire with a simple PVC jacket. Both were 2 meters long. They were connected to an ABX switch box allowing blind fold testing. Volume levels were set at 75 Db at 1000K Hz. A high quality recording of smooth, trio, easy listening jazz was played (Piano, drums, bass). None of us had heard this group or CD before, therefore eliminating biases. The music was played. Of the 5 blind folded, only 2 guessed correctly which was the monster cable. (I was not one of them). This was done 7 times in a row! Keeping us blind folded, my brother switched out the Belden wire (are you ready for this) with simple coat hanger wire! Unknown to me and our 12 audiophile buddies, prior to the ABX blind test, he took apart four coat hangers, reconnectd them and twisted them into a pair of speaker cables. Connections were soldered. He stashed them in a closet within the testing room so we were not privy to what he was up to. This made for a pair of 2 meter cables, the exact length of the other wires. The test was conducted. After 5 tests, none could determine which was the Monster 1000 cable or the coat hanger wire. Further, when music was played through the coat hanger wire, we were asked if what we heard sounded good to us. All agreed that what was heard sounded excellent, however, when A-B tests occured, it was impossible to determine which sounded best the majority of the time and which wire was in use. Needless to say, after the blind folds came off and we saw what my brother did, we learned he was right...most of what manufactures have to say about their products is pure hype. It seems the more they charge, the more hyped it is. |
Yup. There's a lot of hype about speakers that I don't understand as well. While I will concur that there is a difference between good speakers and bad speakers, it's a lot more to do with build quality than with esoteric materials.
If you open up a set of genuine professional near-field monitors of the sort that people use in actual mastering suites (Yamaha, Genelec, Tannoy, etc) you'll find that most of them are built out of regular ole' MDF, and contain one tweeter and one main driver. No exotic woods, none of this business with sixteen transducers arranged in some proprietary pattern. They just happen to use decent quality electronics, a pair of good drivers, and are assembled with a certain level of attention to fit-n-finish. |
After spending some time in home theater retail and demonstrating an shitty $200 HTIB and then an outstanding component unit for under $1500 and the customer saying "I don't hear a difference, give me the cheap one, but give me that $3000 LED TV" made me realize its all based on the user. Granted I rarely got an audiophile since I worked in "big box" stores, but on occasion they would come and my audio and accessory percentages shot threw the roof!
Theres got to be a thread somewhere for the $2hdmi vs. $100 hdmi. I got my mc1000hd2m for $37($120 retail) and its registered for life and the tip doesn't snap off when I plug or unplug it :-\ |
Originally Posted by Joe Perez
(Post 449173)
Yup. There's a lot of hype about speakers that I don't understand as well. While I will concur that there is a difference between good speakers and bad speakers, it's a lot more to do with build quality than with esoteric materials.
If you open up a set of genuine professional near-field monitors of the sort that people use in actual mastering suites (Yamaha, Genelec, Tannoy, etc) you'll find that most of them are built out of regular ole' MDF, and contain one tweeter and one main driver. No exotic woods, none of this business with sixteen transducers arranged in some proprietary pattern. They just happen to use decent quality electronics, a pair of good drivers, and are assembled with a certain level of attention to fit-n-finish. The single most important part of a speaker is the crossover. The chosen components have the largest impact on the sound and that's the bottom line. If a "by the book" 3000Hz crossover is just thrown in between two random drivers, it'll sound worse than mediocre. If you spend some time properly measuring the drivers and modeling the crossover, you can optimize so-so drivers to sound amazing. The problem is that mass-market manufacturers would rather save $.50 on a capacitor and lose the sound quality to make the money |
Well, these days most of the pro stuff uses internal amps, so passive crossovers are a non-issue.
And they don't have to be profanely expensive, either. You can get Mackie MR5s for $150 each, Yamaha MSP-3s for $165 ea, Alesis M1As for $300 a pair, Fostex PM1-Is for $380 a pair, etc. None 'em are gonna break windows a mile away, but for home theater / audiophile use, they're grrrreat. |
Originally Posted by Joe Perez
(Post 449215)
Well, these days most of the pro stuff uses internal amps, so passive crossovers are a non-issue.
And they don't have to be profanely expensive, either. You can get Mackie MR5s for $150 each, Yamaha MSP-3s for $165 ea, Alesis M1As for $300 a pair, Fostex PM1-Is for $380 a pair, etc. None 'em are gonna break windows a mile away, but for home theater / audiophile use, they're grrrreat. |
Originally Posted by Joe Perez
(Post 449090)
It's a function of current, not power, and it depends on the length and the load impedance. CAT5 is 24ga (some of it is 23ga) so just find a conversion chart and solve for amperage by finding the square root of (watts / ohms). The nominal resistance of 24ga is between .03 and .05 ohms / ft.
The simple answer, however, is that you can pump as much power through it as you want until it starts getting hot enough to either melt or set something on fire. There are no absolute cutoffs when it comes to "acceptable" power loss in a transmission line for the sort of application you're talking about. Any absolute figure that someone quotes you (unless it is referenced to either a specific rise in temperature or a specific voltage drop) will be purely arbitrary. We don't use it for speaker cable, just for line-level signals. The most power we'd transmit down one would be an AES/EBU (AES3) signal, which is ~5 volts RMS into a 110Ω load, so ~45 milliamps, or ~230 milliwatts. (Wow, I never really did the math and realized how much power there really is going through an AES3 transformer!) slebidia - I've seen that test before. Monster cables suck, so using them was kind of a bad example, but interesting none-the-less. I would think a coat hanger would at least create a slight hiss. Maybe it was too short a distance. I also agree everything is really hyped and it's more about "owning the best" than it making a difference. I have $300 EPOS speakers and they're excellent. The build quality really does make the difference, though I've heard that if you make the cone out of real wood, it can produce a (subjectively) more accurate sound. There are people who make enclosures out of concrete. All the problems I have are with things resonating since I don't have enough sound absorption. Oh, and crossovers...very important. I'm assuming active vs. passive is the same as like active vs. passive PFC? Do active adjust the crossover frequency based on the range of the signal being provided? I'm only really familiar with the passive ones. |
Originally Posted by TrickerZ
(Post 449239)
Oh, and crossovers...very important. I'm assuming active vs. passive is the same as like active vs. passive PFC? Do active adjust the crossover frequency based on the range of the signal being provided? I'm only really familiar with the passive ones.
passive means after the amplifier and unpowered (capacitors, inductors, resistors) active means before the amplifier using the unamplified signals, powered (op amps, sallen-key topology, etc). it's not a control scheme with feedback if that's what you're thinking (though those do exist, it's not meant by "active" here) edit: I take that back... in a sense, it does have feedback at the op amp level. |
Ah, ok. That makes sense. Active as in amplitude adjustment. I was thinking active as in frequency adjustment. I guess it's kinda like an EQ for each driver. Probably easier to get a good cutoff with it before the amp too.
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Originally Posted by TrickerZ
(Post 449318)
I guess it's kinda like an EQ for each driver. Probably easier to get a good cutoff with it before the amp too.
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Originally Posted by Joe Perez
(Post 449325)
They typically have a degree of equalization for each section; basically a high-pass on the main driver, independent level controls for both amps, sometimes a three-band EQ. Basically just enough to neutralize the room. Beyond that, you really don't want any EQ on something that's intended for mastering.
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Originally Posted by y8s
(Post 449356)
well there's EQ that takes something not-flat and makes it flat (ie ideal reference) and EQ that makes it sound different. anything inside a speaker should remove coloration, not add it. leave that to your hi fi or whatever.
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that's what I meant by cheap vs. well designed cheap. having that linearity in something super cheap is not guaranteed.
oh and time-windowed FFT over spectrum analyzer to avoid standing wave resonances :) |
http://imgs.xkcd.com/comics/fourier.jpg
Show me a modern spectrum analyzer that doesn't support FFT. |
Originally Posted by Joe Perez
(Post 449408)
http://imgs.xkcd.com/comics/fourier.jpg
Show me a modern spectrum analyzer that doesn't support FFT. |
Originally Posted by y8s
(Post 449570)
You do realize that I'm talking "under 500 dollars for hardware and software exclusive of an already-owned typical PC" right?
Seriously, check out the Asian scopes that are being sold today. It's getting hard to find one that doesn't natively support all the fancy functions that required $2,000 Tek plugins a decade ago. |
sounds good. the next things we need is a maximum length sequence burst and to play it at a few watts of power and a relatively flat measurement mic....
course reinventing the audio measurement and design software through typical analysis tool channels would be silly. |
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