Amps for MRX sub

[lifeloverwg]

No. Internal volume is different w/ 2 singles and the tuning is different. IME, the LF response will be pretty close, but the maximum SPL will be higher on the 2 MRX singles.

 

 

True the max SPL for 2 MRX should be a couple dBs higher than 1 SRX, but no way the LF extension gets near the 718. MRX 518 claims a -3dB at 45hz compared to a claimed -3dB of 34hz for the SRX. Maybe you pick up 5 or 6 hz from coupling, (although even that much would surprise me) but no way you gain near 10 or 11hz. Besides, the SRX just flat out sounds better than the MRX.

 

Winston

[agedhorse]

Yup, didn't say it didn't.Yah, past discussions haven't been too productive due to the various manufacturers not being public with what theirs actually does . Folks had to actually measure a Behringer DCX2496 to figure out if it had peak or RMS limiters as they don't tell you and their tech support didn't even understand the question (it is RMS BTW). Most amps don't have published peak (20ms?) ratings either.

I think you are confusing several terms.

"RMS" power is based on the RMS voltage.

Peak power is based on peak voltage and for a sine wave is ALWAYS 2x the RMS power.

20mSec is a burst power rating that's not typically used in pro audio, though the marketing folks are seemingly interested. It does have some value when used appropriately, and for LF material, 20mSec is way too short.

Peak and RMS detectors come in many flavors and based on several different approaches. You can have very fast RMS detectors and very slow peak detectors.

[RoadRanger]

Peak power is based on peak voltage and for a sine wave is ALWAYS 2x the RMS power.

But for a typical musical signal (high crest factor) it can be quite a bit higher than that as the power supply doesn't "wilt" as much as it does with a full swing sine wave. A 100w rms amp could be 400w peak. Many home sound system amps and them cheap "DJ" amps have quite high peak to rms ratios.

[heath_eld]

did someone say that there is a difference between using 2xmrx 518 compared to 1 x MRx 528? How would those differ?

[agedhorse]

But for a typical musical signal (high crest factor) it can be quite a bit higher than that as the power supply doesn't "wilt" as much as it does with a full swing sine wave. A 100w rms amp could be 400w peak. Many home sound system amps and them cheap "DJ" amps have quite high peak to rms ratios.

 

 

No, you are comparing apples to oranges.

 

The crest factor argument relates to the burst power capabilities which can also have peak and RMS values.

 

100 watts RMS will always be 200 watts peak for a sine wave. Every signal is made up of a summed series of sine waves of the different harmonics.

 

The maximum theoretical peak power can be calculated from the maximum power supply voltage (minus driver/output losses) and there will be an RMS equiv. for that peak that will be close to 1/2 that value for the given time slice. It won't be exact because it's not a pure sine wave but will be close enough for this discussion.

[agedhorse]

did someone say that there is a difference between using 2xmrx 518 compared to 1 x MRx 528? How would those differ?

 

 

Yes, the LF extension will be slightle better with the 2 x 518 because there is more internal volume and the tuning is slightly different. Not a huge amount, but some folks seem to think the 218 will be better than 2 x 118's which is not true.