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In Reply to: RE: Many many problems posted by Tre' on March 16, 2016 at 17:24:47
This is a really good, and somewhat surprising point, which I had never considered before, and cannot say I fully understand. I think it merits further reading, thanks for raising it.
Follow Ups:
A 6db loss for every doubling of distance only applies outdoors (in a wide open space) where there is nothing for the sound to bounce off of and return to the listener.I have mixed a lot of live rock shows outdoors but only once, that I can think of, was in a wide open space with nothing for the sound to bounce off of.
That was the Cherry Festival, Traverse City Michigan. The stage was set up at the end of the peninsula facing back towards the city. **The concrete all around the peninsula is lower than the grass area and the one small building is about 250ft from the stage.**
This is a case where a recording made off the 2 bus (the signal from the mixing console that drives the amplifiers that drive the speaker system) can sound good.
Normally the mixer has to compensate for the "ills" of the room and a 2 bus recording (known as a "board recording") sounds awful.
Being totally outdoors, the only thing I was compensating for was the speakers. The board recording actually sounded a lot like the show.
Note, a normal SPL meter measures only direct sound. They do make special SPL meters that measure direct plus reverberate sound.
But you don't even need one. Just walk around your room and listen. 6db is a lot, 12db is huge. You will hear spl differences as you move around your listening room but they will be due to standing waves within the room, not distance from the speakers. And unless you have some really bad standing waves in you room you will not find large spl changes. Changes in the sound, yes, but not large changes in overall spl.
BTW "If we are dealing with a 94.6 dB speaker, and let's say the single ended 6L6 puts out say 8 Watts (being generous), this gives a maximum SPL at 1m of about 103.6dB" I think we all have stereos.Two 94.6db speakers, each with 8 watts driving them to 103.6db spl, would yield 106.6db spl total.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 03/16/16
I'm not sure any of this is relevant given the fact that La Scalas are so bass deficient. In fact, lack of bass response is the fly in the ointment relative to most "high efficiency" speaker systems. Unless you want to bi-amp, or you have room for a huge straight or folded horn, it won't be a full-range system.
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Buy Chinese. Bury freedom.
Audio seems to be a series of compromises. With folded W bass bins you get tight and low distortion bass, but it doesn't go very deep, but that can be easily solved by adding a subwoofer. However, a 15" direct radiator in a ported box can never be made to be as low distortion and as tight sounding as horn bass. You get to choose.
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Big speakers and little amps blew my mind!
Edits: 03/18/16
~!
The Mind has No Firewall~ U.S. Army War College.
nada aqui
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Buy Chinese. Bury freedom.
!
The Mind has No Firewall~ U.S. Army War College.
You can believe that I understand the working principles of horns. Your remark wasn't about distortion, it was about accuracy. A speaker isn't accurate if bass is down 5 dB at 50 Hz. I don't think that even qualifies as hi-fi.
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Buy Chinese. Bury freedom.
20 Hz, the Khorn bass bins stomp the flab and gratuitous grumbling of any bass reflex design you care to name. As for the LaScala's ... and no bass below 50 CPS... I hope your room is BIG enough to swallow a 56 foot wave if you are so adament about having your 20 HZ.
The Mind has No Firewall~ U.S. Army War College.
Edits: 03/24/16
"I hope your room is BIG enough to swallow a 56 foot wave..."I don't think you understand how pressure waves work. 20 Hz is easily accomplished in the confines of a car if the drivers are capable. More to the point, it really doesn't matter if your musical tastes favor the midrange. Accuracy requires the ability to reproduce the entire range. If a speaker can't do that, it's less accurate than one that can.
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Buy Chinese. Bury freedom.
Edits: 03/24/16
I personally think there is more to accuracy than bandwidth. It may not even be the most important.
This conversation is making me scratch my head. Any direct radiator that is flat down to 20Hz is going to be 18 to 21" in diameter. That's so large that it's going to be put in it's own enclosure, and that makes it a sub-woof-er.
Maybe we should start a thread on the speaker asylum, and see how many multiway speakers we can come up with that are flat from 20Hz to 20kHz. I can't think of any, and I bet the ones that do have serious accuracy issues of their own for reasons other than bandwidth. Not that any of this matters, as I'm sure you are just being pedantic for your own amusement.
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Big speakers and little amps blew my mind!
This issue isn't one of absolutes. All else being equal , a musical reproduction system that is 3 dB down at 25 Hz is inherently more accurate than one with a 3 dB point of 55 Hz. Yes, low distortion counts for something, as does SPL. However, it simply isn't meaningful to say that one or the other of these attributes is most important, and to claim a system to be more accurate as a result of that characteristic alone. That's why I responded to the statement regarding the accuracy of bass horns the way I did. As a blanket statement, it isn't true.
"Any direct radiator that is flat down to 20Hz is going to be 18 to 21" in diameter."
That's not true either.
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Buy Chinese. Bury freedom.
Here, something incontrovertible, a horn loaded woofer design {or any compression driver implemented correctly} is 10 {ten} times lower in distortion than any cone or dome. If your mind cannot count that as important, your ears surely will.
The Mind has No Firewall~ U.S. Army War College.
The following in terms of import... The room Trumps all other considerations, followed by the speakers and I daresay the preamp before the amp I have used transformer driven volume controllers...not dead and lifeless but definitely not as realistic sounding... Overload a small room all you want... It is not realistic.and surely, not accurate.
The Mind has No Firewall~ U.S. Army War College.
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Have Fun and Enjoy the Music
"Still Working the Problem"
Like 50 Hz... A known fact.
The Mind has No Firewall~ U.S. Army War College.
That would exclude a large number of stand mount "monitors", most Lowther designs, smaller Magneplanars some JBLs and Altec A5s & A7s.
You're a tough listener / measurer.
Edits: 03/24/16
I suppose it wouldn't be life without compromise... I like the la scalas a lot but I can see why someone who is after deep bass response would be turned off them. I haven't got the space or budget for a more involved horn loaded system with better LF extension, and I really enjoy the sound of the la scalas. Plus, I don't like to imagine moving them again :)
This makes a whole lot of sense. Concert sound looks like a real challenge, especially outdoor concerts!
The reason I didn't account for the sum of two speakers, is I tend to listen to a fair niumber of recordings with exaggerated stereo separation, so I didn't want to consider that the two channels are contributing equally. Under ideal circumstances they would be but I prefer to have my system designed for worst case.
I still think 8W is inadequate for those speakers under a wide range of conditions, based on empirical experience, but the how and why of it acoustically are not so much within my grasp as I thought.
One thing I do wonder - if it's the case that the volume doesn change much with distance,
Why is it that when I use arrays instead of usual speakers, that the volume seems more consistent with respect to distance? I mean empirically if I have a line array playing I can walk right up to it and to the other side of the room and the volume is the same everywhere,
Whereas when I listen to, say, a bookshelf speaker it seems louder up close.
Is it just that the reverberant field begins farther away for the bookshelf speaker ?
"Is it just that the reverberant field begins farther away for the bookshelf speaker ?"
For those particular speakers it must be...I guess.
I do know that the more directional the speaker is, the farther away the reverberant field begins.
"I still think 8W is inadequate for those speakers under a wide range of conditions"
That could very well be. I didn't meant to commit on that position per se, just the technical reasoning behind it.
P.S. I had another thought about the line array. It's kind of hard to get close to all the drivers at the same time vs. a small 2 way bookshelf speaker.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
"could very well be. I didn't meant to commit on that position per se, just the technical reasoning behind it."
And thank you for doing so, more knowledge is always better!
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