ok, i was after a set of 6.5inch boston pros, but instead ended up getting a set of 5.5", some advice from a guy i dont trust much implyed that a 5.5inch is a better sq speaker but a 6.5inch is louder.

NOT in relation to boston pro's but in general is there much diffrence between a 5.5inch and a 6.5inch?? what are the pros and cons of each?? and best way to optimise each?

The 6.5's will have a stronger midbass meaning they will play lower frequencies before distorting, this may be the difference between high passing them at 90hz instead of 80hz. You will probably notice a difference but it's not going to sound bad.

If you install properly and use sound deadening you will get them to sound really nice.

Pro's would be they are cheaper and more likely to fit the stock location of your car. Con's would be lack of midbass.

I don't understand about 5.5 being better sound quality. Regarding 6.5's being louder, say you played a tone at 85HZ, they will both play the note but as you increase the power the 5.5 will distort before the 6.5. So at an adequate listening level you will have to high pass them at a higher frequency. They aren't going to be louder, but they are able to be played louder.

Unless of course the 6.5's are more efficient. But to be honest I wouldn't let that sway me in my decission as to which to buy. I would primarily be looking at which size suits your install best.

i would say that the 6.5 may play louder as their sensitivity is higher per w and their efficiency doesn't drop off as soon at lower hz !

6.5s will have more authoritive midbass. In terms of detail levels, if they're both quality drivers there will be nothing in it.

This is the 5 vs 6 inch debate.
People will always say that 6 inch is the way to go if you could fit both.
However, I've been told five inch is better for imaging and upper midrange due to its smaller lighter cone.
In a very old Hot4s (October 2001), they compared Focal Polyglass 136V(five inch) to the 165V(six inches), they said the six inch was better for bass and male voices while the five inch was better for complex upper midrange and female voices.
However, they said the six inch gave a 'warmer, less detailed sound.'
The conclussion advised five inch with small subwoofers which produce bass and sub bass for realism or six inch with large (12 or 15) subwoofers but would have musical defiencies as due to lack of midrange detail

I ran and still own some MTX black Gold 5s and they were much sweeter than the black gold 6s in the midrange region. Female vocals were incredibly sweet and smooth. The down side was they had to be HP @ 200hz to get any decent volume out of them, so I added Black Gold 8s as midbass drivers and was stoked with how they performed. The 6s will have better midbass but its hard to get decent midbass out of 6s anyway.

IMO stick with 5s and work out how to get some 8s in there. This will be far superior to the results you would get from running 6s and virtually assure you of Bass up front. I cant say wether your 5s will have sweeter midrange than 6s as havent compared the 2 but it is likely to be the case.

If you use 8s Id still suggest using no larger then 12 inch subs, as this will provide a perfect transition from fronts to subs
peace
Cyberpunky

That Hot4's Mag article is a good read. Very valid points. Really its a decision your ears will make. An additional dedicated midbass will be awesome. Sometimes hard in a lot of cars. I run 5's with 10inch woofers and I have a trophy to show, it does the job.

Personally I prefer 5" drivers as opposed to 6" drivers, especially if you're after midrange details and sufficient upfront midbass. With 6" drivers, even when you can go slightly lower in terms of bass reproduction due to larger cone area, the fact that it's larger tend to make midrange reproduction a bit "muddy". Whereas with 4" drivers you get excellent midrange sound but no midbass at all.

The trick is to find 5" drivers with high dB sensitivity. Look around, see if you can find one. Or maybe experiment a bit by using home drivers.

Cheers,

Bon