Axiom Home Page Forums General Discussion Stereo Power Handling when removing binding post connecto

Simple Question after reading the other thread about Mojo's lab calculations on the power handling of the ALFR seperate channels.....

If I remove the binding post connector's on my M60ti dual binding posts how do I calculate the power handling?

The specs are rated at 250 watts RMS / 1000 watts dynamic, well at least the v4's are, maybe the m60ti is different, i couldn't really find anything solid that lists the old specs.

Does the spec change if the woofers are seperated from the mid and tweeter? I'm thinking yes as we all know the woofers take the majority of power to drive the low frequency.


This is more of a thought experiment really as I don't have amps to try anythinh with. In fact i've got 3 pairs of speakers sitting here and not one amplifier or intergrated or reciever to play anything right now. My m2's look really sweet. I like the black oak. It's better than i expected it to be.

The short version: I'd not worry about it. Bi-wiring, as you may already know, the power draw is the same. Bi-amping works as long as both amps have the same gain. Both sides (woofer, mid/tweeter) will consume only the current (power) it needs.

Longer version:
An amps power rating is really a spec of the the amount of current it can supply to all the speakers connected to it ... i.e. the power an amp can supply to two speakers is a lot more than if it was driving 10. So, already the amount of power available to each speaker varies with the number of speakers and time. A speaker is designed to use voltage as its input. It will draw what ever current it needs to do its thing (at that voltage and frequency). Power = voltage * current. The other side of the coin limiting an amp is it's voltage rails. An amp with high voltage rails might drive an 8 ohm speaker to it's full rating but not a 4 ohm speaker. The reverse is also true ... the same power amp with low rails might drive a 4 ohm speaker to it's full rating but not an 8 ohm. Both will result in clipping. The voltage rails are a hard clip. The power limit clip (current) comes into play once you start continuously asking for it. Extreme clipping is, IMO, what kills most speakers.


With 250 watts continuous and 4x dynamic I'd be pretty sure you're safe on the M60ti either way you connect them.
Hope that was the answer you were looking for.

Thanks Rich. That is a good answer to my post. I should've added more to my post I now realize.....

If I was to have whatever number of seperate amplifiers I wanted to put into each channel. L and R woofers and L and R mid/tweet on an m60ti, what amplifier power could the woofers handle versus the tweeters and midrange? (Bi-amping scenario i guess.) (As a footnote i personally dont think bi wiring does much of anything but I think that bi amping does as I think the extra power added to each channel or pair of channels would improve overall headroom if you used the right power amounts and would also improve channel seperation i believe.)

Put another way, the 250 watt RMS spec is for the whole system, woofers midrange and tweeters. If I seperate them does the power handling spec change? The tweeters and midrange will draw what current they need and the woofers will draw what they need. I guess im trying to ask does the same thinking apply that mojo proposed to the ALFR ratings he spewed out. (the trouble maker that he is really.... )

Requoted here from the other thread:
"The triple woofers are 800W, each mid is 75W for a total of 300W and each tweeter is 25W for a total of 100W. Hence 1200W."

Not that im going to do this but I could give each channel its own amplifier to improve headroom and thus overall dynamics. (Keepng in mind Andrews recent video about head room). If thats not the case then why bother with the dual binding posts on the speakers?

I hope im explaining myself better.....

The triple woofers spec is for the HP drivers. The regular woofers are probably 119.63478W each.

250W is for the whole thing.

Axiom put the dual binding posts on there because customers asked to bi-wire and bi-amp. They didn't want to lose sales. It also makes them look more "upscale" for snobby audiophiles.

Don't waste your time.

Good enough for me. So basically put a reasonably powered amp that matches the RMS or close and call it good.

Indeed.

I just noticed the M60s can now be equipped with HP drivers. When did that happen?

The power spec stays the same with HP drivers. So the power is limited by the cross-over?

The HP option on m60's has been there for a quite awhile. As long as i've been surfing around here, so about 2 years. Yeah i noticed that too, the spec doesn't change for HP, doesn't change for m80 either going from non hp to hp. It must be a different spec if they are designed to handle more power, the power spec should change.

Using our agreed logic above (get an amp near the RMS max of what your speakers are rated for) an ADA-1250 would do the trick for me with 225 watts RMS at 8 ohms my m60ti with the upgrade path to either m100 or LFR. Or do I spring for an ada-1500 with my giant room and run that with my m60ti? Should be fine i think....it will supply 325 rms into 8 ohms.

Mojo has been quite on how he came up with that. My recommendation would be to drive each with 2 channels of the same amp. In that case everything works and the issue is moot. Trying to optimize amps to each is kind of impractical and as you say a mental exercise.

if I were to attempt it I'd measure the current that's being drawn by each speaker input at several frequencies and calculate it from there. But it takes some equipment you probably don't have. A function generator and a decent multimeter. You can do it manually or if both of these can be controlled by computer automated. Then guesstimate a nominal impedance from each input graph

I'd pass this by Mojo to see if he thinks this cheat might work ... but you might get away with measuring the DC resistance of each input and use that to get a rough estimate of how the power in would be divided. Not the best way but it might give a good enough result ... by the way the power split is inversely proportional to resistance.

Kodiak,
My guess is if two M60s can fill your room that an ADA1250 will be plenty. Can't imaging anyone getting close to it's max power in ... unless you like to listen from 20' to 30' away or like Mojo wear muffs to sit closer

I've never explored this but here's my thinking on bi-wiring ...
if your speaker wire size is marginal the current draw of the woofer may effect the waveform distorting the higher frequencies. By bi-wiring you can eliminate that distortion.

It is one reason I like to see a wire resistance less than a hundredth of the nominal speaker impedance.