#1
Hey guys. So I found a good deal on a Marshall dsl15 and I was wondering if it'd be loud enough to gig with. (Although I'll likely get it anyway as I think they sound great, I have other amps that are loud enough) and I realized that although I've been gigging for several years, the 4 amps I've owned have been very different. I used a 50 watt solid state head and ran the master at around 7 through a 1x12. I've used a peavey 6505, the 60 watt combo, and I don't think I ever turned it past about 4 or possibly 5. Yet I ran my 100 watt valveking at around 9. And the vs100 combo I use anymore I only run around 5 or so. Sometimes 6. Yet they all sounded the same volume to me. Is the wattage rating for amplifiers really that terrible?
I'm just kinda curious what yalls thoughts are on the matter. Those much wiser than me haha. I just realized that it seems out of place to me
#2
Knob settings tell you nothing. You can calculate volume with math or you can measure it with a meter. Both ways work pretty well.

Math method: Speaker SPL rating at 1W1M plus amp output in dbw= clean headroom output.
Ex: EVM12 is 100db SPL, HRD is 40w or 16dbw= 116db clean headroom. Plenty loud for nearly any indoor ballroom/roadhouse gig. (When you play the Coliseum, bring a mic.)

Measurement method: Buy a decent SPL meter on Amazon, set it to "A" weighting and place it 1M from the speaker, crank the amp, check your measurement in db SPL.

110-115db clean is plenty unless you are in a deaf-metal band screaming at 120db. Then you will need more amp and good ear protection.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis
Last edited by Cajundaddy at Oct 17, 2016,
#4
Based on previous posts I've read on the DSL15 I don't think it will be loud enough.
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#5
Oh likely not. My jca20 head is barely loud enough. It is. But not clean.
But no I just was curious how most people figured that out.
#6
How loud's your drummer? He's the man setting the onstage sound level.
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#7
Not particularly loud. He uses 3/8 sticks and he's lazy lol. So not particularly loud
#9
I just turn it up all the way then roll it back as the other members start bitching!

Just kidding!

It's different for every amp and every room. My Blackstar sounds crazy loud at 6-7 volume, my jet city only needs about 2-3 on the volume to make the hairs on your neck stand up.
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#10
Quote by Cajundaddy
Knob settings tell you nothing. You can calculate volume with math or you can measure it with a meter. Both ways work pretty well.

Math method: Speaker SPL rating at 1W1M plus amp output in dbw= clean headroom output.
Ex: EVM12 is 100db SPL, HRD is 40w or 16dbw= 116db clean headroom. Plenty loud for nearly any indoor ballroom/roadhouse gig. (When you play the Coliseum, bring a mic.)

Measurement method: Buy a decent SPL meter on Amazon, set it to "A" weighting and place it 1M from the speaker, crank the amp, check your measurement in db SPL.

110-115db clean is plenty unless you are in a deaf-metal band screaming at 120db.


On the money. Knob settings tell you nothing about how many watts you're using or about how much volume you're putting out. Wattage ratings really don't tell you much, either.

I prefer the measurement method, honestly. If you have an SPL (you can get free apps for your iPhone) you can measure how loud your drummer is playing. You'll probably need at least that much and probably more.

In fact, better than an SPL is an RTA (Real Time Analyzer) that will tell you how loud you are over a wide frequency response.

We found out a long time ago that if you crank up a 100W Marshall to rock levels, the bottom end disappears. It just doesn't have enough power to put out high decibels at low frequencies. That's why your bass player is probably using in excess of 500W (I have a *far* from the highest end bass amp that outputs 1500W). A lot of speaker companies rate their speakers' SPL (efficiency) at 1000 Hz which, for a guitar, is pretty high (the fifth-fret A on the high E string is 440Hz, the 17th-fret A is 880Hz). Note that a standard six-string electric guitar begins with a fundamental at about 82Hz (open low E), and that it takes four times as much power to produce any note an octave down at the same volume. If you're really cranking a 1000Hz note at, say, 110 dB SPL, it would take 64X that power to produce 125Hz at the same volume
#11
That makes sense.
So, just more out of curiosity, why do we rate amplifiers in terms of wattage instead of decibel output based on a baseline speaker or something? Because your right, wattage doesn't mean much. My 60 watt 6505 was much louder than my 100 watt valveking. Considerably so. So why use wattage instead of a maximum decibel level?

I suppose that sounds ridiculous, we've been using wattage for years. But it seems like that would be more helpful to me
#12
Also, again just out of curiosity, do you mean that lower notes take more power or energy to produce or to hear?
I may be completely full of it but I was fairly sure that different frequencies take roughly the same energy amount to produce but lower notes are harder for humans to hear and recognize. I know generally humans can only hear as low as about 20hz but as high as 10000hz. That would make a high A at 880hz less than 1/10 of a general humans recognizable auditory level. Maybe it holds no meaning to how loud something is. I just say that because I know that infrasound can be immensely loud, more than loud enough for humans to die from it if it was a higher frequency, yet not notice it terribly much because it's too low to recognize.
#13
Something to remember, if I remember this correctly.... even at a high wattage multiple speakers may not translate to as many watts as a single speaker amp, hence the possible loudness issue... however multiple speakers give you options of not having to use mono sound settings..... for example if you are running a 2x12 pin a 100 watt head you are only truly getting 50 watts as it splits between the 2 speakers, where say you're using a 60 watt 1x12.... the full 60 watts is pumping into that single speaker, so you are physically getting the full wattage
#14
Is that why a lot of amps will have say, a 16 ohm output and 2 8 ohm outputs?
#16
Lgarretto somebody tools me more about that in the past.....i know it's something to with the output.... the lower the more bassy sounds it picks up, and the higher the setting the better for high frequency sound.....my vox head and cabinet combo had a mono set up for 4 and 16 ohms and stereo jacks for 8 ohms
#17
Quote by Lgarretto
That makes sense.
So, just more out of curiosity, why do we rate amplifiers in terms of wattage instead of decibel output based on a baseline speaker or something? Because your right, wattage doesn't mean much. My 60 watt 6505 was much louder than my 100 watt valveking. Considerably so. So why use wattage instead of a maximum decibel level?

I suppose that sounds ridiculous, we've been using wattage for years. But it seems like that would be more helpful to me


wattage isn't the only factor in terms of how loud an amp is. speaker efficiency, cab style and even the acoustics of the room all factor in. the difference between 60 and 100 watts is actually pretty minimal. rule of thumb is you need 10x the wattage to be twice as loud. what the higher wattage does do for you thoug is give you clean headroom (volume before amps goes into distortion and not necessarily the good kind). with a 15 watt amp in a band you're likely going to have to crank the amp up to be heard which means clean tones can kinda go out the window and distortion may actually distort more than you want. if you are playing in say a traditional jazz band then you're probably ok but hard rock and metal not so much.

as for why amps are rated in wattage it's a traditional method that has been in place for a long time and is basically used for all sound producing items. I believe the answer to the power needed to reproduce low notes has to do with physics so a little out of my area.
#18
I don't know about any frequency boosts or anything from that, I thought it was just the resistances for the wiring.
I mentioned it because every Marshall I've ever seen has one 16 ohm output and 2 8 ohm outputs
#19
Okay. Like I said, I was just curious.
As for why I started this I found a deal on a Marshall dsl15 and I've been kinda looking for one and I was curious as to whether or not it would be loud enough. Although I'll likely get it either way. My other Marshall is loud enough easily.
That and I was also curious how most people decide whether an amp is loud enough for them or not.

But I learn things every time I get on this forum. It's great. That's why I ask all you older and wiser guys the questions haha
#20
Your question is a good one because there is much confusing misinformation being put out by companies - especially with solid state amps which use ridiculous wattage numbers and which are insanely misleading - I had a "300 watt" solid state amp as my first amp - it was no louder than my current 30 watt tube amp.

My advice is to always test an amp in the field with a drummer before committing. Then you'll know if you have enough loudness and enough clean headroom, if that's what you're after. Don't be afraid to buy an amp and return it, or to rent one for a night if it's a popular model.
#21
Quote by Lgarretto
Also, again just out of curiosity, do you mean that lower notes take more power or energy to produce or to hear?
I may be completely full of it but I was fairly sure that different frequencies take roughly the same energy amount to produce but lower notes are harder for humans to hear and recognize.


Lower notes take more power to produce at the same volume (Sound Pressure Levels (SPL)).
Essentially, that's a objective physics issue.

How you hear various frequencies is another thing entirely.

Quote by Lgarretto

So, just more out of curiosity, why do we rate amplifiers in terms of wattage instead of decibel output based on a baseline speaker or something? Because your right, wattage doesn't mean much. My 60 watt 6505 was much louder than my 100 watt valveking. Considerably so. So why use wattage instead of a maximum decibel level?

I suppose that sounds ridiculous, we've been using wattage for years. But it seems like that would be more helpful to me


We have been using a maximum decibel level throughout the industry wherever there's a speaker included with the amplifier. The only segment that doesn't is guitar amps. For example, I have a set of studio monitors (KRK Rokit 8's). These active speakers have 100W of total power amplification (divided 72/25 between a LF driver and an HF driver). The specs list "Max Peak SPL:109 dB". Honestly, that's not particularly helpful since it doesn't tell you at what frequency (or range of frequencies) that SPL was measured, but it's a start.

Wattage output is rarely actually measured from tube guitar amps, period.
For the most part, you get a rule of thumb guess/approximation. But it would still be misleading because there's no way of knowing what losses we should expect due to cable runs, speaker inefficiency, impedance differences and acceptable distortion levels.
#22
Quote by reverb66
Your question is a good one because there is much confusing misinformation being put out by companies - especially with solid state amps which use ridiculous wattage numbers and which are insanely misleading - I had a "300 watt" solid state amp as my first amp - it was no louder than my current 30 watt tube amp.


Solid state amps aren't at fault -- but their marketing companies are. The usual wattage quotes include RMS, program, and peak ratings. Program ratings are often twice what the RMS ratings will tell you, and the Peak ratings are often four times what the RMS ratings are. If the rating system used was "peak" watts, then it's likely that your amp was closer to 75W RMS (which is what I'll usually try to compare). 30W tube amps are often driven into distortion, where their actual wattage can double. At that point, some relatively minor differences in speaker efficiency can make a larger difference in SPL.

Quote by reverb66
My advice is to always test an amp in the field with a drummer before committing. Then you'll know if you have enough loudness and enough clean headroom, if that's what you're after. Don't be afraid to buy an amp and return it, or to rent one for a night if it's a popular model.


Yup.