Bass on guitar PA?

Horseflesh · #1 09-21-2020, 03:56 PM

I have a general purpose music PA with a high-Z input for instruments such as guitars. Among the various digital settings is an EQ setup for a bass guitar, so it certainly seems to be a supported use.

I keep reading people getting scolded for using a bass on a guitar amp, though. Is there anything I should keep in mind, besides being careful about the volume?

YamahaGuy · #2 09-21-2020, 04:13 PM

Although a dedicated amp would likely be more feckful, my nephew played a 5 string bass through my PA (which at the time was mostly a single powered 12" speaker and a small mixer) for three years with no ill effect. As they say, run what you brung.

Steve DeRosa · #3 09-21-2020, 04:32 PM

Several factors come into play here, and while a few guitar amps - '59 Bassman, '65 Super Reverb RI (I've used the latter on a couple occasions - great old-school tube tone), some half-stacks with a sealed cab - will handle a bass at low- to medium volume, the strong low-frequency information will blow a typical guitar speaker in short order, especially in an open-back cabinet; simply put - don't do it...

Similarly, while a decent coffeehouse-style PA system like yours can IME handle a bass in a pinch (as long as you have an input pad and a woofer/subwoofer that'll reproduce the low strings adequately), just because you can doesn't necessarily mean you should. There's a whole bunch of compact, lightweight, reasonably-priced bass amps on the market with the kind of power/headroom (the latter of which you really won't have with a general-purpose PA) that required a 60-pound head and refrigerator-sized cab a generation ago - and when $300 gets you a 100W, 22-pound Fender Rumble 100 1x12" combo, IMO it makes more sense to go that route and let the PA do what it does best...

Horseflesh · #4 09-21-2020, 09:17 PM

Thanks much for the replies, I appreciate it. Lots to think about.

jonfields45 · #5 09-22-2020, 06:04 AM

My duo has been gigging for the last 10 years putting bass guitar for about a third of our repertoire through our single high and behind PA speaker. As of late that is a QSC CP8. Never a problem with it or a predecessor. The primary users of these products are DJs and they are not known for going light on bass.

Paleolith54 · #6 09-22-2020, 07:38 AM

Quote:

Originally Posted by Horseflesh

Thanks much for the replies, I appreciate it. Lots to think about.

The rig you showed has a sub, right? As long as you keep the volume down you'll be fine. You'll have to try it to see how it actually sounds.

Horseflesh · #7 09-22-2020, 11:12 AM

Quote:

Originally Posted by Paleolith54

The rig you showed has a sub, right? As long as you keep the volume down you'll be fine. You'll have to try it to see how it actually sounds.

It's a full range array and the manufacturer calls it a sub, but maybe it's arguable if it is just a woofer. The specs say:

Frequency response (-3 dB): 51 Hz to 20 KHz
Frequency range (-10 dB): 45 Hz to 20 KHz

According to The Internet a 4 string bass is 40Hz to 400Hz.

So, it seems like it should work ... but isn't optimum. The computer has an EQ preset for bass, so I assume it will be smart enough to filter out what it can't reproduce. (It has clip protection built in too.)

Hmm, what is a typical bass amp's frequency response... I did id some searching and I see a wide array of opinions on what range you actually need to play bass. Can't find manufacturer specs for a Fender Rumble 100 for comparison. So, I am more confused than when I started. :P

Paleolith54 · #8 09-22-2020, 12:36 PM

Quote:

Originally Posted by Horseflesh

It's a full range array and the manufacturer calls it a sub, but maybe it's arguable if it is just a woofer. The specs say:

Frequency response (-3 dB): 51 Hz to 20 KHz
Frequency range (-10 dB): 45 Hz to 20 KHz

According to The Internet a 4 string bass is 40Hz to 400Hz.

So, it seems like it should work ... but isn't optimum. The computer has an EQ preset for bass, so I assume it will be smart enough to filter out what it can't reproduce. (It has clip protection built in too.)

Hmm, what is a typical bass amp's frequency response... I did id some searching and I see a wide array of opinions on what range you actually need to play bass. Can't find manufacturer specs for a Fender Rumble 100 for comparison. So, I am more confused than when I started. :P

This is why I say you need to just plug it in and see what you think. It's easy to over think this, to no benefit. I've heard so many expert pronouncements that, IMO, simply aren't true; you can't get good vocals through 15" speakers, you can't play loud rock through a Bose stick setup, you can't play acoustic through an electric amp, any subwoofer smaller than 18" is a waste, etc. It all depends on what you are doing, where you're doing it, how loud, how long, to what standard, etc.

So: yes, it can work. Will it sound like you want it to? You have to decide that.

Horseflesh · #9 09-22-2020, 12:59 PM

I DO tend to overthink things, it is true!

Sound quality I am not worried about. Anything I play will sound like I am electrocuting a horse anyway. It's the safety of the equipment that I want to guarantee. You read some stuff, it sounds like the PA will collapse into a black hole and destroy the Earth if you hook up a bass.

Paleolith54 · #10 09-22-2020, 01:19 PM

Quote:

Originally Posted by Horseflesh

I DO tend to overthink things, it is true!

Sound quality I am not worried about. Anything I play will sound like I am electrocuting a horse anyway. It's the safety of the equipment that I want to guarantee. You read some stuff, it sounds like the PA will collapse into a black hole and destroy the Earth if you hook up a bass.

It won't. Start low volume, go up from there.

Horseflesh · #11 09-22-2020, 03:38 PM

See, you're an enabler... Now I am going to have to buy a bass.

Thanks everyone!

Horseflesh · #12 10-24-2020, 06:47 PM

I thought I owed the forum a reply: no magic smoke has left my PA system after using it to practice bass guitar.

It may not be the right gear for a gig, but I'll never know since I am not sure I am ever gonna learn to play this thing... but I am having fun.

FrankHudson · #13 10-24-2020, 09:12 PM

Low volume and I'm not a pop 'n' slap guy, but I've used my old JBL EON 15 inch powered PA speakers with bass through a mixer. A compressor or limiter may help keep overly aggressive transients at bay, and I'm usually using at least a bit of compression on electric bass.

Steve's tip on the Fender Rumble is worth considering. My teenager wanted to learn bass and I bought a used one to enable that. Light, more than enough power for folk and garage rock in the 100 watt model and for low volume folk gigs you could get away with even the cheaper Rumble models--but read that spec again: 22 pounds for a bass combo. I think some bass guitars in their hard case will outweigh that amp, so you don't need to go smaller to get something easy to load in/out.

Horseflesh · #14 10-24-2020, 09:42 PM

My PA has a mixer with effects built in so I do have some compression turned on. The FX suite is not guitar-specific... just generic reverb and so on. My setup would absolutely sound more "real" with something like the Rumble 100. It does seem to get universal praise and it is on my watch list for sure!

Steve DeRosa · #15 10-25-2020, 09:56 AM

Quote:

Originally Posted by Horseflesh

...My setup would absolutely sound more "real" with something like the Rumble 100. It does seem to get universal praise and it is on my watch list for sure!

Two of my bass-playing friends - one of whom has a gear inventory that would be the envy of many a full-time touring pro - went to the semi-local Guitar Center, on two different occasions, with no specific intention of buying an amp...

They both left with Fender Rumble combos, and use them as their go-to gigging amps (replacing, in one case, a very impressive head/bottom rig)...

There's probably an Election Day Sale coming up at one of the big-box dealers -take the plunge, you won't regret it...