Go read 'The loudspeaker 1-2-3.
And Troels's test of the different mid candidates for them )
His main issue as i understood it is the response he got on the intended baffle, with a 5-6 db peaked shelf in the midband and the corresponding phase shift etc.
It is barely visible on the mfg graph, it was evident on his wider test baffle and got even worse on the finished and narrower baffle, and that was a 50cm wide baffle, the behaviour gets worse the narrower it gets.
I think he had a similar note about the 6nd410 for a build.
Unlike the OPs proposed 8nmb420 and MB500 which both are well behaved drivers which implements easily with passive XO's
I've looked long and hard for well behaved 'pro' 8" mids and from all the options i also ended up with the 8NMB420 as the choice.
The AE looks great in all respects until you see the frequency response behavior. The same behavior the TD6M exhibits.
They need to be crossed steeply and fairly low if you want to remove 4-6 db peaks and dips up top, i guess it's possible to notch them out with some work and a lot of parts.
There is also the resonance from most likely it's frame/magnet assembly that's quite obvious around 1k.
And that is version 2 of the drivers, that clearly have some traits that should have disappeared in the new revisions.
For the cleanest midrange, I would look at a 5 or 6 inch unless you were going to use a midrange driver. An 8 just can't get up to most tweeters.
I am liking, on paper, the CSS and Purifi as well as some SB and Santori. So far, paper is still my favorite. My current mains are a SEAS ER18. I think any tiny advantage in stiffness can me made up in the tweeter and not have to deal with as nasty breakup so shallower crossover which is easier to get the phase right. Active/DSP is a different story.
I am liking, on paper, the CSS and Purifi as well as some SB and Santori. So far, paper is still my favorite. My current mains are a SEAS ER18. I think any tiny advantage in stiffness can me made up in the tweeter and not have to deal with as nasty breakup so shallower crossover which is easier to get the phase right. Active/DSP is a different story.
The cleanest in paper, clean distorsion in the highs, descent low end should be a ScanSpeak 6" revelator if the project is 2 ways... expensive... maybe for a good reason.
The discovery seems a no brainer in its price range, more low end than any 8" pro due to their high Fs. While you always have to deal with the baffle stepp. Maybe going 4 ohms could be easier if BSC with passive filter...
The discovery seems a no brainer in its price range, more low end than any 8" pro due to their high Fs. While you always have to deal with the baffle stepp. Maybe going 4 ohms could be easier if BSC with passive filter...
I agree with tvrgeek and diyiggy.
why limit it to 8”?
if we start with intended passband eg. Definining midrange as; say C4-C7 (~262Hz to ~2.1KHz) there’s definitely several 6.5” that beats many 8” midwoofers.
if you need it to go down cleanly to the subwoofer eg. 120Hz or 80Hz that might change.
But then with a bigger driver you might give up on the high end; and need a robust tweeter and/or waveguide to meet the 1.x crossover point.
I haven’t seen any 8” that does 2KHz better than a 6.5”
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All is about you want to cross-over and the trade offs you want to live with. Or what else driver you use. 8" is feasable with a strong tweeter than goes low...but the off axis response will be not as nice than a littlier driver for the soundstage quality. There are solutions like wave guides, 2" paper tweeter with an aluminium dustcap, etc. Seas has a 2 way kit with a 10"...so it is possible but what you winn in the low you lost it in the highs.
Look for Quattro projectbon Troels Gravsen site for illustration. And also 3 ways classic that uses a 8" w/o sub. If you have a sub and wants a 2 ways then well chosen 5 to 7" will make your life and sound better.😎
Look for Quattro projectbon Troels Gravsen site for illustration. And also 3 ways classic that uses a 8" w/o sub. If you have a sub and wants a 2 ways then well chosen 5 to 7" will make your life and sound better.😎
I wouldn't say it's bass driver with it's Xmax, but could be nice down to 80-100Hz