528hemi
492 posts
Jan 22, 2016
5:07 PM
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How does volume increase as you add additional amps.
play through 1 5 watt amp
split and play through 2 amps, 3 amps, 4amps
How would playing through 4-5 watt amps compare with playing through 1 15 watt amp volume wise?
528hemi
Last Edited by 528hemi on Jan 22, 2016 5:08 PM
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1847
3134 posts
Jan 22, 2016
7:54 PM
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not sure it is any louder... you do get a wider dispersion of sound.
i have several delay units that allow multiple amps.
you can run one amp dry and add echo to the left then a longer delay to the right. brian may and eddie van halen do this. as well as others.
the lone wolf terminator pedal is an excellent device i can run the kinder box to the bassman and a echo to a smaller amp
with out the overdrive, just a faint echo.
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if you appreciate what you have...
it becomes more.
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Harpaholic
793 posts
Jan 22, 2016
8:11 PM
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This may help, if you double your wattage, you increase your volume by 3db.
If you go from 25 watts to 100, its a 6db increase.
If you get a Bassman none of that matters.
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Barley Nectar
1076 posts
Jan 22, 2016
10:02 PM
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I sometimes run two amps. My Arion SAD-1 delay is stereo out. Select which amps to use depending on the room and expected volume levels. I'll spread the amps out if possible. This is also how Adam runs his rig I believe. This creates a very rich, full, sound field and allows me to roll the VC back some. I too use a smaller amp on the wet side like 1847 does.
I believe that Harpaholic has answered the OP's question...BN
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dougharps
1120 posts
Jan 23, 2016
6:46 AM
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I understand that sometimes you can get a more complex sound by using two different amps.
I have some questions about, "double your wattage."
If I use two different 15W amps, each with a 10" speaker, will I be able to be just as loud as using one 30W amp through the same two 10" speakers, assuming proper impedance matching?
Or are there other factors at play? Perhaps you can achieve higher volume before feedback with two linked amps than with one more powerful one, or is it vice versa?
My understanding is that to double volume you need 10X the wattage. But I never have been sure that by using two amps (or more) you could add their individual wattages to equal the volume of a significantly larger amp of equal wattage, assuming the identical speaker types and numbers.
For some reason I think it is more complex than that...
Don't the specific characteristics of each amp have significant impact on how multiple amps sound and what volumes they attain before feedback compared to using one large one of equal wattage?
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Doug S.
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Barley Nectar
1078 posts
Jan 23, 2016
9:00 AM
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Well, we probably need an audio engineer for this one.
Doug in your scenario a zillion things will effect the outcome. Amps used, placement, room acoustics, speaker efficiency, exc. All things being equal, it should be a simple matter of wattage used. Mathematically speaking and from my experience, Harpaholic has it right. The books I have read say the same...BN
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dougharps
1123 posts
Jan 23, 2016
10:55 AM
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Thanks! All things equal, add wattage...
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Doug S.
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528hemi
494 posts
Jan 23, 2016
11:32 AM
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Let me ask this another way.
Does a 5watt amp plus another 5 watt amp = one 10 watt amp.
I believe harpaholic is talking about a single amp.
Are amps played together additive in wattage and volume?
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Barley Nectar
1079 posts
Jan 23, 2016
12:43 PM
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IMO....Yes
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528hemi
496 posts
Jan 23, 2016
1:39 PM
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I want to hear 4 kalamazoos ( 20 watts x 4 10 inch speakers) :)
I guess 8 kala's is equal to a bassman. haha
Last Edited by 528hemi on Jan 23, 2016 1:42 PM
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SuperBee
3277 posts
Jan 23, 2016
2:42 PM
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About the most confusing and least-well understood topic which gets discussed here I think.
I can't claim to understand it. I think if you keep adding speakers you need more power to drive them, but I wonder about the impact of splitting your signal...I guess you just turn the amps louder than you'd have a single amp. Or daisy chain them is probably better. But also the spread of sound is important in perceived loudness. And then there's the question of the speaker's capacity to make loud noise...it's not just the diameter of the cone which counts huh? Must be how far it can move back and forward? Seems to me if the speaker can move a greater distance in the same time as another, the speaker that moves further will be louder...and it will take more power to move such s speaker to its capacity...so wattage of an amp is just an indication of watt it would be capable of driving, and it's the combination of amp and speaker which is really gonna determine the peak volume of the rig.
So if that was the case, there would be a point where using two amps of same power would be louder than 1 amp with multiple speakers. But I don't know how to calculate that...even if I'm on the right track...
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Harpaholic
794 posts
Jan 23, 2016
2:52 PM
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Here is a great article that will help explain it. Its not complicated, but when you add the human element perceiving volume differently, it not an exact science.
http://geoffthegreygeek.com/amplifier-power/
Last Edited by Harpaholic on Jan 23, 2016 2:53 PM
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Barley Nectar
1080 posts
Jan 23, 2016
3:27 PM
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Well the issue of splitting the mic signal is a whole nother ball of wax. If you daisy chain amps together Series) each amp will weaken your signal from the mic. If you use a Y cable or some kind of setup to drive each amp from a single mic (parallel) you will get a different result. Either way the mic element will be loaded up to a point where is is not operating within it's design parameter. I don't know the specifics of all of this.
For Harpaholics explanation to work properly all amps must receive the same strength signal. ( All things equal)
Gerg Heuman did hook up a wall of Zoo's at one time, he was not impressed...BN
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SuperBee
3278 posts
Jan 23, 2016
3:34 PM
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He (geoffthegreygeek) doesn't deal with speakers though. He just asserts that the amplifier power is equal to acoustic power and then describes relationships between acoustic power and decibels and sound pressure. So I accept all those calculations and I'm sure I don't know what double the volume means (any more than all those people who rated their chance of getting home from work safely each day as "99%" realised they said they expect to have 3.65 incidents per year which will cause them not to get home safely), but I don't think he established that a 20 watt amp plugged into my twin 8" cab is going to be 6 decibels louder than my champ through the same cab. Or to put it another way, whether a twenty watt amp through a 12" speaker will be perceptibly louder than the same amp through an 8" speaker.
Last Edited by SuperBee on Jan 23, 2016 3:36 PM
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dougharps
1127 posts
Jan 24, 2016
4:35 PM
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Rather than bring two amps I pick one I have that seems to best fit the room. I always have the option of mic'ing if I find that I am under powered, and always have a 57 on hand at a gig.
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Doug S.
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1847
3138 posts
Jan 24, 2016
5:04 PM
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Either way the mic element will be loaded up to a point where is is not operating within it's design parameter. I don't know the specifics of all of this.
i believe the terminator pedal address part of this issue, however i also do not know all the specific.
you are splitting the signal in half, but since we
only turn the volume to about three.
we can now turn up the amp to about five and achieve the same amount of volume before feedback.
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if you appreciate what you have...
it becomes more.
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Fil
95 posts
Jan 24, 2016
5:24 PM
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Doug, why do you always have your 57 on hand at a gig? In case you have to go direct to the PA? Im a neophyte jammer with a lot to learn.
Thanks
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Phil Pennington
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Fil
96 posts
Jan 24, 2016
6:05 PM
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Doug, Just to be clear, I'm reading your comment about the 57 as it's an alternative to micing your amp, that it's not necessarily your go to mic.
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Phil Pennington
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garry
621 posts
Jan 24, 2016
6:50 PM
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In my experience using two amps with a splitter, it makes it sound different, but does not make it appreciably louder.
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dougharps
1128 posts
Jan 24, 2016
9:28 PM
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@Fil
If I am playing a gig I always have backup harps, cables, and a backup mic. The gig must go on, and if I am hired, I do the job. Sometimes I bring along my EH 44 Magnum amplifier as a backup amp.
The SM57 is versatile and can be used to mic amps, for vocals for me or a guest, or for playing harp to the PA or an amp with an impedance matching transformer. It makes a good all around backup mic and it doesn't take up much space. I also have one of Greg Heumann's XLR volume controls, so that adds extra options to the 57.
Generally if I play a gig I use my Ultimate 58 for vocals and harp to the PA, and to play through an amp I use my Shure 585SAV or for straight blues, my Astatic Biscuit that has a Shure CM element with one of Greg's volume controls. I have a number of other vocal and harp mics that I use from time to time, but the ones I named above are my "go to" mics for gigs, and a 57 is my backup mic.
******
With regard to discussion about splitting your signal, I think you will probably lose tone as well as volume if you just split the signal with a Y connector. You are putting two impedances in parallel, which lowers the overall impedance into which you send your mic signal. You also risk ground hum when you link two amps. You need a splitter that maintains the level of impedance your mic needs and perhaps a ground lift. The terminator pedal should do this, or perhaps an active DI or a preamp with two outputs. You could try splitting the signal after a pedal, as the pedal output may be more accepting of different impedances than the mic would be.
At least, that is my understanding of it. If I am not correct, please let me know.
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the code was taxec2
Doug S.
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Fil
97 posts
Jan 25, 2016
6:26 AM
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@doug, thanks very much. Lot of good learning in your answer.
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Phil Pennington
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isaacullah
3124 posts
Jan 25, 2016
9:29 AM
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RE: using a splitter. A mono "y" splitter cable will work in the sense that the mic will feed its signal into the input of the two amps. In practice, however, it almost always leads to tone bleed and lowered volume, as the mic will not be loaded correctly (ie. there will now be an impedance mismatch). The tone/volume bleed can only be avoided with a true mixer circuit. There are two types of mixers: passive or active. The passive circuit uses two low value resistors to separately load each leg of the "y". There is some small volume loss with this approach, but drastically reduced tone bleed and crossover. I've built several of these, and they seem to work very well for most purposes. I use resistors of <1k Ohm values, and just solder up three jacks in a small box (one input, two output). Better still is an active mixer, which buffers each leg, so they don't bleed any tone or loose any volume. More difficult to make, and needs batteries, but works very well too. If you have a delay pedal with one input and two outputs, it has an active mixer circuit built in, so should work very well. Otherwise, you can buy small battery operated mixers or A/B/Y pedals that will offer the same performance.
RE two amps volume increase. EDIT. Much of what follows was wrong. Was up late and not thinking correctly. See second post below for important corrections. Correcting this post here so as not to confuse anyone reading it later!
It's my understanding that two identical amps with two identical speakers move twice the volume of air, and so will be louder than only one of the amps on it's own. The volume form those two amps would be additive, but not doubled. They'd be equal in power to a single 10 watt amp. And then again, I think you'd also need the same square inches of speaker cone to move the same volume of air. So, say your small amp is 5 watts with a 10" speaker. The speaker has an area of (5*3.145)^2 = 247.276 sq.inches, so the 10 watt amp needs a speaker area of 494.55 sq.inches. You'd need a speaker with a radius of root(494.55)/3.145 = 7.071", which is a 14" speaker. So, to equal the volume of two 5 watt amps with 10" speakers, you'd need one 10 watt amp with a 14" speaker (or two tens with a similar parallel or series impedance to the speakers in the 5 watters) (let's say 8 ohms). A 10 watt amp likely is going to cost more than the two 5 watters combined, so you are better off getting the two smaller amps and running them in parallel. Further, you then get the ability to widen the sound field by spreading the amps apart (or facing one slightly left and one slightly right), and you can also use your stereo delay pedal to add some stereo perception with a very short slap-back delay from one side to the other.
If you wanted to get twice volume increase, you'd need to use ten times the watts because output volume is logarithmically related to wattage. So to get twice the volume you'd need a 50 watt amp. Not exactly sure how much more speaker area you'd need, but probably at least two to four times as much? Alternatively, you could use ten 5 watt amps! Lol!
EDITED to correct grave mistakes.
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YouTube! Soundcloud!
Last Edited by isaacullah on Jan 26, 2016 2:03 PM
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Barley Nectar
1086 posts
Jan 25, 2016
8:31 PM
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isaacullah...You say that two 5 watt amps will be as loud as a 50 watt amp with a 14" speaker. I cannot disprove that statement with mathematics but I feel you are mistaken. I have played a lot of amps, big and small, and IMO, that is not going to happen...BN
Last Edited by Barley Nectar on Jan 25, 2016 8:32 PM
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isaacullah
3125 posts
Jan 26, 2016
7:31 AM
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@BarleyNectar. Sorry! Made a boneheaded mistake! Meant to say that if you want to double the volume, you do need to go up 10 x watts (ie, 5 to 50). But if you *double up two amps*, you ADD the watts (ie. 5 +5 = 10). I forgot to write that last part, and then befuddled the rest of the statement. What I *meant* to say is that you would need a *10 watt amp* with a 14 inch speaker to equal the volume of two 5 watt amps with 10 inch speakers. Yeah, no way that two 5 watters equals one 50 watter!!! That was a huge beainfart on my part!
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YouTube! Soundcloud!
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GamblersHand
591 posts
Jan 27, 2016
5:00 AM
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Another related question
For bigger bar gigs I often use two amps (7.5W Marble Max and a 6W VHT) and a Y-splitter. I use an early 90s GB
Any idea how much benefit I'd get from an impedance matched active splitter such as a Lone Wolf Terminator?
For effects I just use a Boss delay - I guess I could run it before the Terminator or just add to one of the amps?
Last question - I've also thought about a squeal killer, although perhaps more for single amp gigs. For the 2-amp set up any recommendations where I should run this relative to the Terminator or delay pedal?
thanks in advance
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HarpNinja
4192 posts
Jan 27, 2016
6:56 AM
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From experience:
Two small amps will sound fuller, maybe a hair louder, but it a 5w amp vs 10w is pretty negligible when it comes to perceived volume.
In addition, you HAVE to split the signal in a way that retains the signal. Passive cables will cause possible loss of tone and volume.
I used to run two Silverface Champs or a SF Champ with a Double Trouble. While the tone was amazing, I still had the inherent small amp problems (and more gear to manage and more space for set up needed).
If one small amp isn't the ideal gigging amp, then two small amps won't be either. Running in stereo is unnecessary almost all the time and people are only wanting to do this for volume (not even the complexity of tone which no one hears anyways).
Your best bet to be heard, IMO, is micing the amp and using a monitor. My solution was a pedalboard direct to a powered monitor that is sent to the board to be front of house.
I never have any issues with tone or volume doing that ever.
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Mike
My Website
My Harmonica Effects Blog
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Barley Nectar
1088 posts
Jan 27, 2016
8:18 AM
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No need for a Squeal Killer with small amps. If you stand beside your amps rather then in front of them, feedback can be controlled easier. I don't use anti feedback devices at all. Some amps I will step V1 down one gain stage. Example:...12AX7--to--5751 but that's about it for me...BN
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1847
3147 posts
Jan 27, 2016
9:54 AM
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gamblers hand...
i believe the terminator pedal is passive, it is best suited for a crystal mic. if you have a boss delay,
that works fine to split the signal as long as you like a wet and dry mix.
i consider the terminator pedal to be super awesome.
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timeistight
1922 posts
Jan 27, 2016
12:41 PM
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"i believe the terminator pedal is passive"
The Terminator couldn't do what it does if it was a passive device. From the Lone Wolf Blues website:"The Terminator is an active FET buffer and isolated splitter with a 10 meg ohm input. The 10 meg impedance is ideal for crystal microphone elements and more than adequate for controlled magnetic elements; in other words, it is perfect for your bullet microphone. Your tone will be fatter and you may find that microphones that have been put away now sound great. "
@GamblersHand: While you can run the Terminator after effects pedals, you'd lose the benefits of the impedance-matching buffer whenever the other pedals were in use. Behind an always-on device like the Squeal Killer, I don't think the Terminator would offer any advantage over a Y-cable connection.
Last Edited by timeistight on Jan 27, 2016 3:53 PM
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Harpaholic
797 posts
Jan 27, 2016
2:08 PM
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Because the human ear hears different frequencies at a non-linear (logarithmic) response curve! There is no hard and fast answer.
Also, a speaker begins to compress as it approaches its upper capabilities, but different speakers vary in their compression curve.
If you take out those two biggest factors, you double the voltage to make it twice as loud
I did the math, four times the watts will double volume.
Some factors are unknown!
Last Edited by Harpaholic on Jan 27, 2016 3:09 PM
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GamblersHand
592 posts
Jan 27, 2016
3:31 PM
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Thanks timeistight, 1847, BN for the replies
I've always avoided extra pedals and other kit - as well as being technically disinclined, so many thanks for the answers to my uninformed questions!
@BN - why don't you think the squealkiller is right for smaller amps? I live in London and often travel by public transport to gigs - so I want to squeeze as much as I can through a light set up. the squealkiller would probably give a little more headroom?
I have replaced the AX in the VHT with an AT. I tried an AU in the Max (it currently runs to about "6&1/2" before feedback kicks in) but I felt it lost some punch and character - but I should try it live
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Harpaholic
800 posts
Jan 27, 2016
3:46 PM
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A 12AU7 will kill the tone of any amp, and can also decrease wattage.
Anyone know if a decibel test was ever done with the Squeel Killer?
Last Edited by Harpaholic on Jan 27, 2016 3:47 PM
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9000
242 posts
Jan 27, 2016
4:39 PM
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GamblersHand, suggest you talk to Jason who makes the squeal killer about appropriateness for a low wattage amp. As I recall he suggests his killer for larger amps than the VHT 6. Not certain that I'm remembering that correctly but I think it's worth following up. He's a great guy!
Jay
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Music speaks where words fail.
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Barley Nectar
1089 posts
Jan 27, 2016
8:43 PM
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http://thesquealkiller.com/about/
If you think it will help, go for it. I think these kind of things are snake oil. Just because your volume knob is at 5 instead of 4 does not mean you are louder. Harpaholic gets it. Is your rig any louder with an anti feedback device? Only a dB meter will tell you. Small amps are not prone to feedback if you know what you are doing. Good luck mate...BN
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GamblersHand
593 posts
Jan 27, 2016
11:23 PM
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Thanks for responses - and I meant to say that I tried an AY not an AU... but still seemed a lose a certain something. I must try it at a jam and see how it goes in a live setting.
@9000 - thanks I'll contact Jason to check
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boris_plotnikov
1093 posts
Jan 29, 2016
8:35 PM
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I experimented a lot with splitting signal to different amps. I also tried to play to PA without amp and the best results I git mixing DI signal to PA with real amp (micked for big room, unmicked for small room).
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My videos. My album with Mikhail Bashakov. Seydel endorser. LoneWolf Blues Co endorser. Harmonica teacher. My facebook.
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