Totally see ur point Bert. The general rule on this forum has been to acquire an amp that will provide 1.8 RMS.
That is only a rule of thumb as individual speaker specs and performance can vary dramatically. Tinkering with some 98 Sensitivity speaks and not a chance in hell that I am going to throw 180% RMS at them.
Makes for a good discussion though.

T.

 

What speakers are you using with 98 of sensitivity?
They are going to be really bright though

 

U giving me speaker advice?

T.

 

LOL, no dude, just comenting

 

I was just curious too.

 

Maybe he has a secret weapon you don't know of? LOL.

 

There are a few big factors being left out here. Installed with proper equipment to be sure the distortion is not present then sure it would be satisfactory for some. The average garage joe who ear sets the gain , I will guarantee will clip that setup. You can run that and most amps far past rated and clip with minimal audible distortion. Always better to have a cleaner higher output than a lesser output easily being driven to clipping. Distortion will always destroy a speaker first before power ( within the mechanical limitations) The mpx at 175 watts per side are modestly audible on interstate speed. Can't speak for the mpx coax. The 1 3/4 rms theory is suitable for headroom and so forth. No 98 db speakers don't need 1 3/4 but can play it, just not pleasing to the ears. It is all trial and error, what works for some doesn't for others. As long as the end result makes the user happy then the goal was achieved.

 

I am definitely not trying to argue but the MPX 165 has an RMS rating of 100w and the MPX 690 has one of 130w. That being said yes the diamond amp still puts out a lower power rating(80 x4 @4 ohm) than the speakers can handle on paper. The big factor that you have to keep in mind is that rms rating (especially for diamond audio) are very conservative for amps. This is because they are trying to stop people from over powering speakers. The micro 4 on multiple Bech tests has proven to have a 30% over all higher output at 4 ohm than what is is listed as. That being the case you are no longer in danger of under powering either speaker. You would also be hard pressed to over power it with this setup as well. However if you do not properly tune it you will catch distortion and do damage the same as you would with any other setup. We spent a lot of time and field testing (on my bike) before we ever felt comfortable recommending this setup. Same as we do with every setup we put together. Also the "Modestly audible" comment couldn't be more wrong. I know from personal experience since I did use this setup for almost a year.

 

This is a forum and we debate. No reason though argue it is debating. Now I would love to see a DUMMY LOAD bench test to back up the power output claim. I know these amps are clear and sound very good. I am considering switching my Arc 600.4 to the new 800.2 on my front stage. Now my comment for the MPX was meant for the 690. Forgot to type the 690. On MY bike the rear 6x9's (mpx690) are modestly audible at interstate speeds (70+). If I fade fully to the rear, I can hear them, they sound good, but solely would be a disappointment if I had a road king with no front stage for example. That's is 175rms to each side. Twice the power you are advising. That is a 3db increase minimum in output. For the mpx165 I cannot comment. I am sure these 2 sets together have a decent presence as a whole. Overall performance wise I find a fair bit left on the table still being powered just with a micro 4v2. This is where opinions differ. Now the new 800.4 would be much more suitible. Some are happy with a level of sound others are not. I am sure that sounds really good but for me I would want much more if I ran 70+ on majority of my riding which I personally do.

 

I too ride 70+ the majority of the time. And yes you are correct that if it was soley the rear speakers they would be modesty audible. That however was not the topic of conversation. We were talking about the entire setup, not just a couple parts of it. You are also correct in saying that some people will be happy with it and some won't. It was one of many possible suggestions. As far as bench test results feel free to speak directly to diamomd as I actually did face to face today and they will be more than happy to share the results. We tested it our selves after hearing the rumors. I can't say I would blame you for assuming I too am speaking in rumor, until I actually saw the results myself I didn't believe it either.