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Post by ragan on Oct 19, 2018 13:47:07 GMT -6
So lets say that 20hz sinewave has a wavelength of 56FT.. Because it does.. To properly recreate the sinewave fundamental, the speaker would have to have an excursion that totalled 56FT, so 28FT inwards, and 28FT outwards.. No speaker that I know of has that kind of excursion, so no speaker can truly recreate a lossless fundamental waveform of 20Hz, regardless of how much space is in a room. Lets say that a speaker of a given size can move about 2.6" in total excursion, which relates to around 1/256th of a wavelength.. Which means that the power at that fraction is very low, but if the speaker is sufficiently tuned for resonation at or near that frequency and the driving power at that frequency is sufficiently large, one could still recreate enough of the 20hz wavelength to be perceptable by the human ear and interpreted by the brain as 20hz. Except that's not how speakers work.
First, you really don't need the full wavelength to produce the frequency from an array*. 1/4 wavelength will do fine, at the expense of a certain amount of efficiency. 1/4 wavelength of 20 Hz is 14.1 feet. That is the distance the mic needs to be from the SVT cab for a 20 Hz wave to form and for the array to achieve coupling. In practice, you don't need that much with a normally tuned bass, as low E is about 40 Hz, so about 7 feet will do. To optimally pick up low end from an SVT cab you need to place a mic at around 7 feet.
Second, your speaker diaphragm does not need to have excursion equal to the wavelength of the lowest frequency. I don't understand where you got the notion that it did - that would make practical woofers impossible. The frequency of the waveform is (obviously) determinined by the frequency of movement of the diaphragm. The excursion of the speaker is one of tywo factors determining the amount of air being moved,analagous to power in an electrical circuit. The other determining factor is diaphragm size. To determine the acoustic power being generated we use..... wait for it........... Ohm's Law in which diaphragm are is analagous to current and excursion is analagous to voltage. (How this translates to Acoustic Watts, I don't know off the top of my head - I'd have to look it up. It really only bears on efficiency of the speaker system, anyway. I DO know that non-horn loaded speaker systems are amazingly inefficient, something like a couple or so percent if you're lucky. One Acoustic Watt is actually quite loud.)
Again, excursion has nothjing to do with the wavelength being produced, and more than frequency has anytyhing to do with the power output of an amplifier.
* - you can, of course, hear some low end at less distance but the efficiency is in the toilet and you won't get the optimum spectrum balance the system was designed for.
He’s not saying you need that 1:1 speaker excursion/wavelength ratio, he’s just saying that if you took YOUR original position to it’s logical conclusion, you would be left with that (clearly false) idea. I think. But I’m still slogging my way through the physics that Svart took years ago and has a good handle on so I’m squarely still a novice in this realm. |
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Post by Tbone81 on Oct 19, 2018 17:35:10 GMT -6
As long as we’re debating physics let’s add one clarifying point to this conversation. Sound travels as a longitudinal wave in air, not a transverse wave. A transverse wave is what we’re used to seeing on oscilloscopes and daw waveforms, but that’s not how they propagate in the air.
Carry on.
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Post by johneppstein on Oct 20, 2018 0:12:26 GMT -6
As long as we’re debating physics let’s add one clarifying point to this conversation. Sound travels as a longitudinal wave in air, not a transverse wave. A transverse wave is what we’re used to seeing on oscilloscopes and daw waveforms, but that’s not how they propagate in the air. Carry on. Indeed it does, a longitudinal wave consisting of compressions and rarifactions of the medium. But this longitudinal wave doesn't have anything to do with the amount of excursion of the diaphragm. (this might be where some of the confusion is coming from.) the excursion of the diaphragm simply creates the compresions and rarefactions. Once created, they travel at the speed of sound in the medium (in this case air.) |
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Post by guitfiddler on Oct 20, 2018 3:49:35 GMT -6
Do you think humidity levels would change the sound being captured?
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Post by johneppstein on Oct 20, 2018 11:24:57 GMT -6
Do you think humidity levels would change the sound being captured? That's a very good question!
Since humidity (and temperature) change the speed of sound in air, I would say that both would affect the sound being captured. Obviously, the more distance involved, the greater the effect. (When doing stage monitors for a live show, the difference in temperature and humidity between soundcheck in a cold hall and showtime condition's with heightened temperature and humidity can be enough to shift the tuning of stage monitors by as much as a full 1/3 octave!)
There is also a natural high frequency rolloff with distance which would change with atmospheric conditions. Whether this rolloff would be significant at the distances being discussed here in another question.
A related phenomenon, which really doesn't bear much on this particular instance but is related, is that high frequencies tend to rise in the atmosphere with distance (according to "Sound System Engineering" by Don and Carolyn Davis). Distances are not great enough for this to be a factor here.
Everything matters. The question is, How much?
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Post by aamicrophones on Oct 22, 2018 13:18:53 GMT -6
Hi John, you are correct that the sound of speed changes with humidity. The speed of sound at sea level can change from 343 m/sec at very low humidity to 345 m/sec for 100% humidity.
Howard Tremaine mentions in his Audio Enclyclopedia book that they would mist the air to increase the humidy on sound stages in the early days of recording dialogue for film.
The speed of sound also varies with temperature. At 35c it travels at 351m/sec in a standard atmosphere and at 15C it travels 340m/sec.
Cheers, Dave
aamicrophones.com
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Post by iamasound on Oct 24, 2018 16:35:32 GMT -6
When I was six years old I was so fast that I could yell "PICKLES" and run to the other side of the room before the sound got there, and then catch it in my Mickey Mantle first baseman mitt, the one perfectly broken in with neet's foot oil, with the ball tucked in the pocket, tied up with a string and left under my mattress for seven days.
That my friends, is being faster than lightening!!!
Now, who wants to talk about sound!
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Post by Guitar on Nov 13, 2018 16:17:45 GMT -6
Wow I love when threads get this deep.
I can't say that there is any good bass amp for a studio. Anything can work depending on your goals. Even DI options can sound quite different to one another.
I've had good luck with SVT, Hartke, Fender Showman, any number of DI boxes and different basses and bassists.
I think the fact that the human ear is very inefficient at hearing bass explains this. It's like what shade of black is that. Oh it's a little more purple black. OK I guess so.
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Post by b1 on Nov 21, 2018 16:15:52 GMT -6
I'm pretty happy with a REDDI if used with a compressor. I'm not a bassist by trade. Sometimes supplementing with something after it's in the box works, depending on what you're doing, but it will definitely get it in the box satisfactorily... I just wanted to see this in print typed from my fingers --> a HUGE Ampeg rig and a place to unfold it in!
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Post by b1 on Nov 21, 2018 16:35:18 GMT -6
In my mind, from the discussion on the previous (fantastic thought provoking) page, A cab of 4x10's and a 15" solo... Mix to taste. I just love 15's on everything anyway. Gotta have at least one!
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Post by Guitar on Nov 21, 2018 16:44:54 GMT -6
In my mind, from the discussion on the previous (fantastic thought provoking) page, A cab of 4x10's and a 15" solo... Mix to taste. I just love 15's on everything anyway. Gotta have at least one! That's what I have here... sounds thunderous |
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Post by b1 on Nov 21, 2018 16:49:12 GMT -6
In my mind, from the discussion on the previous (fantastic thought provoking) page, A cab of 4x10's and a 15" solo... Mix to taste. I just love 15's on everything anyway. Gotta have at least one! That's what I have here... sounds thunderous Yeah, there's a depth there you don't forget after being bitten by it!.. love me some 18's too! |
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Post by mulmany on Nov 21, 2018 18:26:31 GMT -6
I am a 4x12 cab guy. Best of the 10 and 15.
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Post by jakeboy on Jan 13, 2019 19:52:40 GMT -6
My tweed 5f1 Champ when pounded with my Hamer CruiseBass and driving a 12” EV alnico coffee can SRO Records most glorious..,, just sayin.
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Post by Ward on Jan 16, 2019 9:09:51 GMT -6
I am a 4x12 cab guy. Best of the 10 and 15. I appreciate and respect that. My own findings have been that a 4x10 and 1 or 2 15s give everything in the bass tone you'd ever need and I haven't had much success with a 4x12 for bass ( I Have a Marshall Bass 4x12 JCM800 1960a) But what do you use? |
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Post by mulmany on Jan 16, 2019 10:30:06 GMT -6
I am a 4x12 cab guy. Best of the 10 and 15. I appreciate and respect that. My own findings have been that a 4x10 and 1 or 2 15s give everything in the bass tone you'd ever need and I haven't had much success with a 4x12 for bass ( I Have a Marshall Bass 4x12 JCM800 1960a) But what do you use? I am using a massive Ampeg V-2 4x12 vented cab. I bought it empty together with a non functional V4-B head. I threw 4 carvin pa/bass speakers in it when I was 16... And never looked back. It's honestly more amp and speaker then most systems/stages can handle. Not sure I ever ran it higher then 4. The guy I bought it from had a SVT with the 8x10 cab, I liked the V4-B/V-2 combo better. When I played out, I had a tuner in my setup, and I let a guitarists use it... He wouldn't unplug after he heard his tone through my rig. It was pretty funny! Now, I only use it on occasion to record, but everyone loves it. |
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Post by mulmany on Jan 16, 2019 13:54:52 GMT -6
There is a v-2 cab on reverb right now for $360.
I liked my price of $50 for both the head and cab. Granted I ended up putting $600 into it to make it all function.
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Post by jazznoise on Jan 17, 2019 5:57:25 GMT -6
I am a 4x12 cab guy. Best of the 10 and 15. I appreciate and respect that. My own findings have been that a 4x10 and 1 or 2 15s give everything in the bass tone you'd ever need and I haven't had much success with a 4x12 for bass ( I Have a Marshall Bass 4x12 JCM800 1960a) But what do you use? We use a 4x10 for bass, but the other guitarist and I both run 2x12's. 4x12's can be great on bass, but I think the tonal overlap is a problem for a lot of 4 piece bands. For recording, what they need essentially is something voiced very differently to the guitar cabs. Recently fixed a Vox AC4TV for a friend of mine recently and we stuck bass through it for a giggle and it sounded great! In a band with a lot of clean guitar, I'd be tempted to use one! |
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ahnc
New Member
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Post by ahnc on Jan 22, 2019 19:09:18 GMT -6
I appreciate and respect that. My own findings have been that a 4x10 and 1 or 2 15s give everything in the bass tone you'd ever need and I haven't had much success with a 4x12 for bass ( I Have a Marshall Bass 4x12 JCM800 1960a) But what do you use? We use a 4x10 for bass, but the other guitarist and I both run 2x12's. 4x12's can be great on bass, but I think the tonal overlap is a problem for a lot of 4 piece bands. For recording, what they need essentially is something voiced very differently to the guitar cabs. Recently fixed a Vox AC4TV for a friend of mine recently and we stuck bass through it for a giggle and it sounded great! In a band with a lot of clean guitar, I'd be tempted to use one! I am new here and this would be my first post. Strangely enough having this very issue recording bass right now. I prefer 12" in a trio setting to help fill the sound out. If I was buying for a studio I would probably go Markbass combo or Vanderkley amp with a 2x12. Both are great sounding modern bass rigs. Probably twice the money Ashdown but worth every penny IMHO. |
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Post by jakeboy on Jan 23, 2019 9:09:21 GMT -6
I also like the bass channel on my Blonde Bassman for bass in the studio. I use the aforementioned EV SRO alnico because it is still minty and able to take a pounding, though I don’t play loud bass when recording.
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Post by jakeboy on Jan 31, 2019 21:33:22 GMT -6
I also LOVE the DI on the Stam 1073mpa.. I foresee using that along with micing a cab for color.
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Post by jakeboy on Jan 31, 2019 21:34:54 GMT -6
I also LOVE the DI on the Stam 1073mpa.. I foresee using that along with micing a cab for color.
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