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Topic: One speaker or two? |
b0b
From:
Cloverdale, CA, USA
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Posted 12 Feb 2018 8:14 am |
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| Steve Sycamore wrote: |
| ... But to create a full planar wave generally a line of speakers at least 6 feet or 2 meters long is required. With a planar wave sound intensities drop off with distance half as much as a spherical wave (3db per meter rather than 6 db per meter). So with a planar wave you get a very even distribution of sound at any angle and reflections off walls, floors and ceilings are very much reduced in comparison. |
Reminds me of the Shure Vocalmaster columns, or the more modern Bose L1 linear array.
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ajm
From:
Los Angeles
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Posted 12 Feb 2018 8:48 am
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Steven Paris: "ajm: you are correct. But you have to be careful to wire the speakers to provide the correct load for the transformer. Two 4 x 12 cabinets wired in series-parallel will produce a 4Ω load."
Got it. In my original post I put the ground rules in there that covered this. In short, no matter how many speakers you add, the total impedance needs to remain the same, unless you can switch the amp to match whatever load you connect.
Note another one of the rules: All of the speakers must be of the same type/model.
Jim Sliff: "It's only true if....."
I laid those rules out in my original post.
If someone wants to come along and add another speaker to their amp, and has no way to adjust for the change in imoedance that the amp will now see, then that is not relevant to our experiment/discussion here. They have changed the rules and introduced a new variable.
However.......As long as you match the impedances and source in some way, why does it matter if the speakers are wired in series or parallel? Remember, we are using a 20 watt (or whatever) source to feed either:
1) a fixed impedance load (be it one or more speakers, the total load stays the same), or
2) we match the source to whatever the total load is.
Steven Paris: "....the simple fact is that two identical speakers driven by the SAME wattage are 3 db louder than one."
Steven said "louder". He did not say an increase in "power". If you follow the rules of our experiment, a single source is either always matched to the load, or the load is matched to the source. Therefore that source will be delivering the same power to whatever total load you have connected.
Note that we are using a single source to drive one or more speakers.
We are not using a 20 watt per channel stereo amp, and comparing one channel driving a single speaker, to both channels driving their own speakers.
bob and Jaydee's set up: I believe that Jaydee uses a stereo processor quite a bit, if not always. I don't know what affect this would have on the actual sounds coming out of each speaker, and then heard as a whole.
It would be interesting to play around with his set up WITHOUT the processor....straight mono..... to see what the differences are if any.
I have seen and heard Jaydee up close several times. I have never heard him sound bad. The only way he's going to sound bad is if he intentionally wants to. |
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Georg Sørtun
From:
Mandal, Agder, Norway
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Posted 12 Feb 2018 9:35 am
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| I'm wondering … while doing your simple math with 4 series and parallel wired speakers to get a defined load, have any of you taken the reduced dampening factor for series wired speakers into account? Won't change your static calculations, but in my experience series wired speakers – coil (L) in series with coil (L) – lose definition in a quite audible way. |
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Lefty
From:
Grayson, Ga.
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Posted 15 Feb 2018 10:44 am
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Mr. Walkers stereo setup with two JBL 15" speakers is the best sound I have ever had. I am unsure about the phasing of the speakers, but they really sound good. The stereo effects don't hurt the sound either. I use the effects sparingly.
I previously used a Session 500 and Music man HD-130 w/JBLs. I cannot imagine carry those around anymore.
Even the session 400 is too heavy these days.
I have a music man RP-100 that sounds good with steel and Tel. I would probably gig with that if I were still playing out.
Lefty |
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Ray DeVoe
From:
Hudson, FL
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Posted 18 Feb 2018 2:57 pm One or two
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I have been trying out some different speaker combinations and in my opinion, I just found one of the best sounds that I have ever achieved.
I normally only take one 15" JBL K 130 powered speaker cabinet out when I play and that's a really great sound in itself. I played yesterday and I decided to take a second cabinet out. The second cabinet was a Furlong 12" variable back split with a Travis Toy Double T speaker in it. I have to say that I always preferred the 15" JBL over everything else but the new Double T 12" is one fine speaker. This setup is probably out of phase as the 15" JBL cone moves inward when the positive lead is connected to the "red" speaker terminal. I was extremely happy with the tone of this combination.
One thing that I have found over my years of playing is that if you are going to use any two speakers, they have to compliment each other tone wise.
The rack equipment in the photo is a Sarno octal tube Revelation and TC Electronics M one. Its extra work carrying that much equipment but sometimes it's worth the effort.
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Zum SD 10 Hybrid, Zum D 10 Hybrid, Emmons SD 10 P.P.
SMS: Revelation & Classic Preamps: Furlong 12" & 15" Splits.
Telonics 500 C: Quilter-T.T.12": Fender T.M. Twin
Last edited by Ray DeVoe on 19 Feb 2018 4:59 am; edited 3 times in total |
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Steven Paris
From:
Los Angeles
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Posted 18 Feb 2018 4:32 pm Re: One or two
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| Ray DeVoe wrote: |
| I have been trying out some different speaker combinations and in my opinion, I just found one of the best sounds that I have ever achieved. Bob may be on to something ? ( out of phase speakers ) I normally only take one 15" JBL K 130 powered speaker cabinet out when I play and that's a really great sound in itself. ( cabinet is powered by a TC Furlong power module ). I played yesterday and I decided to take a second cabinet out. The second cabinet was a Furlong 12" variable back split with a Travis Toy Double T speaker in it. I have to say that I always preferred the 15" JBL over everything else but the new Double T 12" is one fine speaker. This setup was out of phase as I have the 15" JBL wired backwards. I was extremely happy with the tone of the combination. |
Are you SURE that the speakers are REALLY out-of-phase? I ask because I believe that JBLs are color-coded different than other manufacturers----the JBL red terminal is actually - (i.e., inward cone movement).
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Emmons & Peavey |
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Ray DeVoe
From:
Hudson, FL
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Posted 18 Feb 2018 5:38 pm
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Hi Stephen.
That's how its wired. Inward movement on the JBL and standard on the Double T.
Regardless of whether it's in phase, or out of phase. It's one terrific combination.
_________________
Zum SD 10 Hybrid, Zum D 10 Hybrid, Emmons SD 10 P.P.
SMS: Revelation & Classic Preamps: Furlong 12" & 15" Splits.
Telonics 500 C: Quilter-T.T.12": Fender T.M. Twin |
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