Looking for Feeback on a First Time Stack

Hey everyone thank you for contributing to the conversation! I think i've dialed things back and am just going to build the subs and use the  Mackie SRM212 V-Class 2,000W 12" Powered Speaker 12 in I already have for the mids and horn. That said, will 2 keystones be good or should i go to 4? My idea is to work with what I have in some respect and build slowly

Edited by DSnow - 14 November 2025 at 5:10pm

Given that the OP has reached a decision I don’t feel so bad about going off topic.

Sorry but this is a fundamental misunderstanding of the problem, there is no issue unless the amplifier is overdriven but people can't stop themselves from turning it up more and more, with that kind of operator a bigger amplifier is just delaying the inevitable it's not preventing anything.

Oh come on! Everyone knows that as long as you don’t clip the amplifier, it is impossible to blow up a drive unit. A gazillion watt amplifier with brick-wall limiter for the win.

Not in response to the above quote, but on the same topic, here are a few comments from two manufacturers. Mainly aimed at anyone who thought my statement above was serious.

To quote JBL’s sound system manual:

Amplifier and Loudspeaker Power Ratings A persistent question is: what amplifier power rating do I choose for use with a loudspeaker of a given power rating? The detailed answer is addressed in JBL’s Technical Note Volume 1, Number 16A; here, we will only summarize those recommendations: 1. For systems that will be stressed with full amplifier output for long periods of time, we recommend that the amplifier’s continuous output rating be chosen to be equal to the loudspeaker’s input power rating. Situations of this sort occur primarily in music reinforcement, where a constant, wide-band signal predominates. 2. For applications, such as speech reinforcement, where there is an operator who controls levels carefully, we can confidently recommend an amplifier with output capability that is twice (3 dB greater) than the loudspeaker’s continuous rating. The rational here is that peak power requirements, often slightly in excess of the loudspeaker’s continuous rating, can be handled with no problem, and it makes sense to provide amplification accordingly. 3. For certain critical monitoring applications, as in recording studios or film postproduction environments, amplifiers may be chosen that can deliver four-times (6 dB greater) power than the loudspeaker can withstand on a long-term continuous basis. The rational here is that the loudspeakers can ordinarily handle midrange and high frequency peaks of short duration that are much higher in instantaneous power than the long-term continuous rating of the loudspeaker. In most speech reinforcement applications, condition 2 above will apply. Note however that there is no absolute necessity to use the larger amplifier unless high acoustical peak levels are anticipated.

EAW states:

Loudspeaker drivers, particularly compression drivers, can usually withstand momentary power peaks well in excess of those they are subjected to in EAW’s power handling testing. Some very dynamic audio signals have high momentary peak levels such as from percussion instruments. Some audio signals, such as speech, have large moment-to-moment variations in levels. To fully exploit the peak capabilities of the loudspeaker and to avoid amplifier clipping, an amplifier larger than the power rating may be needed to reproduce the peak levels in the audio signal. For audio signals with low dynamics, such as heavy metal rock or highly compressed music, an amplifier with a rating at or below the power handling specification might be needed to avoid overstressing the loudspeaker’s thermal capabilities. On the other hand, a loudspeaker rated at 500W continuous (or RMS, continuous, etc.) might be used to reproduce background music at low levels. In this case, perhaps only a 25 watt amplifier would be needed to reach the desired acoustic level.

What does not often get discussed, is that loudspeakers present a reactive as well as resistive load to the amplifier. Power factors of 0.4 -0.6 are not uncommon. Reactive loads do not dissipate energy. It is “reflected” back to the amplifier which then needs to dissipate it. On the whole class D amplifiers cope with this better than class AB. Larger amplifiers are designed to be able to dissipate more energy and cope with higher currents demands. This is why it is, in my opinion, why it is better to over-rate the amplifier. Simply so that it further away from its maximum capability and is less stressed.

But, as JBL stated,  “where there is an operator who controls levels carefully”

For some historical context the article “Music Power Rating – Help or Hindrance?”, by Norman H. Crowhurst, in Electronics World, October 1960 is worth a read.

Hey everyone, I ended up getting a Crown I-Tech 6000 Two-Channel Power Amplifier which will power my 2 tapped horn subs running B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm (3400 Watts handling) in each box. I don't plan on running the subs at 3400 watts and am hoping the 6000 watt amp i have will give me enough headroom for a small room.

The Furman "thing" is to protect the system from electrical issues outside of my control.

DSnow wrote: Hey everyone, I ended up getting a Crown I-Tech 6000 Two-Channel Power Amplifier which will power my 2 tapped horn subs running B&C 18SW115-4 18" Professional Neodymium Subwoofer 4 Ohm (3400 Watts handling) in each box. I don't plan on running the subs at 3400 watts and am hoping the 6000 watt amp i have will give me enough headroom for a small room. I'm now looking at protection for my system and came across this https://furmanpower.com/products/asd-120-2-0 - Furman ASD-120 Do ya'll think it will be enough to protect a small system?