[Cristian135]

hi friends i'm looking for information about the harman amplifier, does anyone know how many watts rms per channel does? It says that there are 12 channels, how are they distributed?

[bri1042]

There aren't 12 channels, it's 12 speakers on 7 channels. I don't know if anyone knows the output per channel (specifically if the sub channels get more power). If someone does, it would be interesting to know.

[Cristian135]

If I read wrong, there are 12 speakers and a power of 360 watts total. I would like to know the watts of each channel to see if I can replace the harman speakers for a focal speakers and continue with the harman amplifier.

[bri1042]

You didn't read it wrong, there are 12 speakers, but each tweeter/mid pair is one channel. If the amp is sending 30 watts down each tweeter/mid channel, that's approximately what each speaker in the pair would get for the frequencies that the crossover allows each one to have...if you are using a proper crossover. That's not how these speakers are setup. The speaker wires go to the mid, then go from the mid to the tweeter through a filter to keep lower tones away from the tweet. I think they present a 2 Ohm load to the amp, just like the underseat's do.

There's a lot of fun math that could go into a long post, but its easier to Google and steal someone else's math if you feel like it. I could also be wrong about the load presented to the amp being 2 Ohms. BMW advertises "360 Watts" but they don't say into 2 Ohms or 4. I'm assuming all the channels are 2 Ohm at the amp since the underseats are 2 Ohm. If the under seats are 2 Ohm and the mid/tweet pairs present at 4 Ohms, everything could get pretty confusing.

360 watts across 7 channels feeding 12 speakers...sending who knows how much power to each channel. I do not think the thing is sending 51 watts (360/7) to the mid/tweet pairs, but it could be. I do not know if they have the subs getting more power than the tweeter/mid pairs, but I think it is.

I do know that the power from the HK amp is lower than I find acceptable to ANY of the channels for adding after-market speakers. The stock speakers are all low resistance. You are likely to lose some volume putting in 4 Ohm aftermarket speakers, but if your aftermarket speakers have a proper crossover instead of just a filter on the tweeter, the "whatever" power into the 4 Ohm load on a set of Focal's will actually be what it's supposed to be, routed by the crossover to the correct speaker, instead of run in series across two speakers. Also, your mids won't end up getting the full spectrum of audio that it can't play thrown at it.

It may still get loud enough, but I think you'll be spending almost all your time at near max volume, and getting all the distortion and unhappiness that comes from the top of an amp's capabilities.


There are LOTS of reasons to get rid of the stock speakers. There are just as many reasons to get rid of the stock amp in this system. If you do one of them and still aren't satisfied, you could always then go do the other...or do them both at the same time to hit it all in one swat.

[Cristian135]

thanks for the explanation, I agree, there is no specification of the hk system, the focal speakers are very good and I had them in my previous bmw .. and when I heard no m2 with hk I thought this sounds good but not at the height of focal and mosconi amplifier, focal are 60w rms speakers if the amplifier hk gave 40-50w rms would be enough to power them.

[bri1042]

If you install the speakers on the stock amp, let us know how it goes. Without available spec's, all we have to go on is guess work and each other's experiences! I already took out my stock amp, but haven't change my speakers yet (will do so soon).

[DanG]

Another complication is that the 2016 and most 2017 M2s have a different HK amp than the 2018 M2.