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Help! I've never bought separate amp components!

#22
I think Carvin makes a very powerful head but it's portable. I think one of the options is bi-amping, where you could send your mid-hi's to the 2 or 4 x 10's and the lows to your 15 or 18' cab. Then you could use either cab alone and run the head full range. Versatile, when bi-amped, very loud.

Up until about 10 years ago, the concept of using a 2 x 10 cab and a 15 or 4 x 10 and 18, was widely accepted. Then all of a sudden the tide changed and it's now considered a bad configuration, even though I still see some bass players use this configuration.

Something just occurred to me. When you go to a concert, the mix of speakers is always, 18" or paired 15" cabs, the mids are various smaller drivers, and the highs are often horns and tweeters. The sound is usually tri-amped or a similar power scheme. If mixing speakers is so inefficient, why wouldn't they just stack 10 4 x 10 cabs and run full range? I'm just wondering why the same concept can't apply to bass.
 
#24
carvinbassplyr said:
So a minimum rms rating is just useless information?
Click to expand...

Show me a minimum rms rating on anything but a special designed cab like the Acme's. Are you damaging your speakers right now by underpowering them? The rms rating on a raw speaker or 99% of the cabs out there are the THERMAL rms limit of the drivers, that is known as the excessive heat limit and exceeding can burn out the drivers. The USEFUL INPUT wattage rating for bass guitar use is most often much lower. Speakers are not light bulbs and at a maximum of 5% efficiency in converting electronic power to sound are better at dissipating waste heat than producing sound.
 
#25
B-string said:
Show me a minimum rms rating on anything but a special designed cab like the Acme's. Are you damaging your speakers right now by underpowering them? The rms rating on a raw speaker or 99% of the cabs out there are the THERMAL rms limit of the drivers, that is known as the excessive heat limit and exceeding can burn out the drivers. The USEFUL INPUT wattage rating for bass guitar use is most often much lower. Speakers are not light bulbs and at a maximum of 5% efficiency in converting electronic power to sound are better at dissipating waste heat than producing sound.
Click to expand...
I'm not saying to run 1000 watts into a speaker rated for 500 watts, but you also don't want to be pushing an amp into clipping/reproducing square waves because it doesn't have the power reserves to reproduce low frequencies @ high volumes. Running a 1000 watt cab for a 500 watt head is WAY overkill. I'm not underpowering my cab. Like I said, my cab is 800 watts rms and my amp is 1000 watts rms. It's not ridiculously overpowered, but my amp has plenty of headroom to use for the lower notes.
 
#28
carvinbassplyr said:
I'm not saying to run 1000 watts into a speaker rated for 500 watts, but you also don't want to be pushing an amp into clipping/reproducing square waves because it doesn't have the power reserves to reproduce low frequencies @ high volumes. Running a 1000 watt cab for a 500 watt head is WAY overkill. I'm not underpowering my cab. Like I said, my cab is 800 watts rms and my amp is 1000 watts rms. It's not ridiculously overpowered, but my amp has plenty of headroom to use for the lower notes.
Click to expand...

Only a BROKEN amp can produce square waves. The best audio designed amp cannot reproduce square waves.
You can make what you have work very well, power output is not constant. Someone borrowing your rig can also easily return with a blow speaker cab. Yes IF a heavily clipped amp does exceed the power input rating of the cab, speaker damage will result (no matter what the "clean" rms rating of the amp is) this is not square waves this is over powering. :)

I strongly suggest the OP read the wealth of info available here on this board, pay particular attention to the sigs from the posters that are at the top of this field. IE agedhorse (Genz-Benz), Jerrold Tiers (Formerly SLM) , Bob from QSC, most of Bill FritMaurice, BbbyBld (Peavey) and several more.
 
#29
B-string said:
I strongly suggest the OP read the wealth of info available here on this board, pay particular attention to the sigs from the posters that are at the top of this field.
Click to expand...

Alternately you could just accept this guy's word for it ^^.

I thought we were done with the underpowering myth. It doesn't even pass muster at a cursory level, nor does it gel with most anyone's actual experience.

I run 485w of head into 300w of cab and I hate it. I can feel the uncertainty of the whole scenario. One wrong move on my part could well kick the teeth clean out of my cab and I'll be damn sure never to recommend these circumstances to anyone else. If I had the money myself I'd amend it, but until I do I've got to be the soul of caution.
 
#32
IPYF said:
I run 485w of head into 300w of cab and I hate it. I can feel the uncertainty of the whole scenario. One wrong move on my part could well kick the teeth clean out of my cab and I'll be damn sure never to recommend these circumstances to anyone else. If I had the money myself I'd amend it, but until I do I've got to be the soul of caution.
Click to expand...

Unless your cab has an extremely high sensitivity/SPL rating, your cab isn't "seeing" full power. Like my Ampeg example...there's a reason why Ampeg SVT's amps run 1400 watts rms bridged @ 4 ohms while their fridge cabs are rated 800 watts rms. With a 98- dB SPL the cabs need that extra juice to wake them up. I'm not saying to be reckless, but you don't need to treat your bass cab like it's made of glass.
 
#33
carvinbassplyr said:
I understand the point you're trying to make here, but you're talking about SEVERELY underpowering the drivers which can be just as bad. Drivers usually have a minimum rms/current rating because there needs to be enough current to move the speaker enough to cool the coil otherwise the diaphragm will freeze (just like tweeters on bass cabs do when you run their volume to low instead of disconnecting it). Then you have to think of the SPL of the cab. 500 watts through a 98dB SPL Ampeg will sound weak compared to 500 watts through a 105dB SPL cab because of the inefficiency of the Ampeg cab. The key to reproducing low frequencies well is headroom. You need extra horsepower, especially with 5'ers, to reproduce those huge frequency waves. A high powered amp that doesn't have to be cranked to be loud will reproduce low frequencies much better than a high strung smaller amp. I use my 4 ohm Epifani PS410 (800 watts rms and 102dB SPL) with a Carvin DCM1000L bridged (1000 watts rms @ 4 ohms). I never have a problem with hearing myself or with the speakers farting out, but I'm also not boosting a ton of sub frequencies to make up for the amp "running out of breath" and I'm running compression.
Click to expand...

Out of curiosity, what do you think happens when you turn your amp down.?

Do speakers blow up with the most severe underpowering... the amp all the way down or OFF?

If you have enough power to achieve desired volume without clipping the amp, anything more is not being used and remains as headroom. A 100 watt amp into a 1000 watt cabinet is going to work just fine in a lower volume environment for example.

This whole underpowering internet myth needs to die a merciful death... just like mixing speaker cabinets with different sized drivers is always inferior... there are quite a few examples where different cabinets are designed to work well together and achieve something that is not possible with a single driver size/type. I have discussed this in great detail before, those that understand the engineering behind it have no problem with the practical applications but those who don't seem to perpetuate this myth. (Note that there are some combinations and tunings that do not lend themselves to doing this, but enough do that making a universal proclamation is preposterous)
 
#34
carvinbassplyr said:
Unless your cab has an extremely high sensitivity/SPL rating, your cab isn't "seeing" full power. Like my Ampeg example...there's a reason why Ampeg SVT's amps run 1400 watts rms bridged @ 4 ohms while their fridge cabs are rated 800 watts rms. With a 98- dB SPL the cabs need that extra juice to wake them up. I'm not saying to be reckless, but you don't need to treat your bass cab like it's made of glass.
Click to expand...

What? A low sensitivity cab means you need more electronic power to have the same acoustic output of a more efficient cab at a lower "wattage" input. It has nothing to do with "waking up" the cab. You are almost touching on some acoustic design choices that cabs like Acme has chosen. Andy made choices to provide a wide frequency response with corresponding loss of efficiency that do require a minimum power input to reach designed response. They also will hit a hard wall when overpowered, but in between is heaven to many savvy accomplished players.

In short: you need more amp power into a less efficient speaker cab than you do a high efficiency cab.

Note efficiency of a cab is SPL (Sound Pressure Level) of a one watt input measured at one meter. The higher the number, more sound pressure is converted from that one watt input to it.

Note the very wise poster above me "agedhorse"
 
#36
alaskaleftybass said:
I think Carvin makes a very powerful head but it's portable. I think one of the options is bi-amping, where you could send your mid-hi's to the 2 or 4 x 10's and the lows to your 15 or 18' cab. Then you could use either cab alone and run the head full range. Versatile, when bi-amped, very loud.

Up until about 10 years ago, the concept of using a 2 x 10 cab and a 15 or 4 x 10 and 18, was widely accepted. Then all of a sudden the tide changed and it's now considered a bad configuration, even though I still see some bass players use this configuration.

Something just occurred to me. When you go to a concert, the mix of speakers is always, 18" or paired 15" cabs, the mids are various smaller drivers, and the highs are often horns and tweeters. The sound is usually tri-amped or a similar power scheme. If mixing speakers is so inefficient, why wouldn't they just stack 10 4 x 10 cabs and run full range? I'm just wondering why the same concept can't apply to bass.
Click to expand...

It is not inefficient to Bi-amp or tri-amp. The bandwidth of a full band mix is very taxing to a single amp. By using multiple amps and splitting up the frequency band you get a much more controllable and faithful reproduction of the mix. Amp size (or power) also decreases the higher the frequency band is with the most power being needed for the low frequencies. The dedicated speaker size to frequency band negates the "mixing of driver debate" as each size of driver only receives the frequencies it is best at reproducing.
You could tri-amp a bass guitar but with so little information (sound) at the higher frequencies it would be a waste of hardware and time.
 
#37
B-string said:
It is not inefficient to Bi-amp or tri-amp. The bandwidth of a full band mix is very taxing to a single amp. By using multiple amps and splitting up the frequency band you get a much more controllable and faithful reproduction of the mix. Amp size (or power) also decreases the higher the frequency band is with the most power being needed for the low frequencies. The dedicated speaker size to frequency band negates the "mixing of driver debate" as each size of driver only receives the frequencies it is best at reproducing.
You could tri-amp a bass guitar but with so little information (sound) at the higher frequencies it would be a waste of hardware and time.
Click to expand...

Thank you B-String. In my "Rainman" understanding you make sense. I just am glad that not everyone is adamantly bashing mixed power/speaker configurations because it seems trendy. Your knowledge reflects in your excellent explanations.
:bassist:
 
#38
Truth #14 - You can safely use any amp with any cab, regardless of power ratings, but if you hear distortion or farting, turn down the volume or the bass knob.
Click to expand...
From Barefaced Bass Mythbusters #1

[Fanboy talk]
I replaced my old 410 + 115 setup with 412. I use Aguilar GS212s at 8 ohms.
This rig can take anything the other musicians throw at me without running out of headroom. When it gets loud, my 500W heads' masters go up to noon, never further.
[/ Fanboy talk]

115 + 410 works. You can see that combination way too often around. If it was that bad, less people would have chosen it. true, the 15 reaches its limit way before the 410 and the 410 will be louder, but in almost every situation that stack will be so powerful that you're too loud well before that limit is reached.
BUT.
Matched cabs really are a lot better. When playing a smaller stage where less volume is required you can just leave one cab at home without sacrificing anything, reducing the schlep by 50% (unless playing a tubehead @ 40kgs).
 

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