Few things I've learned while working at _______(Certain studio monitor company, I'll talk more in August )...

Passive Radiators, great for listening, but I don't like it for production. I'll be using 2 21" passive radiators for a 21" sub that I did a fair bit of design work on. As a result it'll be flat, in room, to some rediculous number in the teens (and xMech = 60mm... that's one way mechanical excursion limit). Why? It'll extend the low end, at what cost? Boominess. Also, I'm not a fan of rear ports, especially with high Q. It loads the back wall/corners too easily...

...Case in point being the Genelec 8050. Damn that sucker goes low, but it's muddy and boomy and loads the front wall. SUPER high Q on the port that faces rearward. I did a waterfall of the 8050 and it's dirtier than my ex. (badum-ching!) They do this to control the excursion of the woofer at low frequencies. At box resonance the excursion of the cone is reduced as it is the driving force of the oscillator (mass on a spring: air in port is the mass, air in box is the spring). I've pulled apart an 8050 and run more tests on it than I would have liked.... or maybe I did like it since I got to pull apart one of the ugliest monitors EVAR!

Adam's don't use ribbon tweeters. They use Heil tweeters. If you think I'm splitting hairs.. I'm not. It's a stiff material. You have magnets front and rear that block most of the sound. 4:1 ratio in 'excursion' to air displacement? Eh... not buying that it's linear. It's wide, which hurts dispersion considerably. They have their port in the right place, though. Does it work? Sure. Does it create good marketing? Yeah, because it's referred to as a ribbon when it isn't a ribbon at all. Ribbon's are great, but they can be MUCH better. I have two patents being written up right now and one is for a ribbon tweeter. The other is for an ultra shallow sub. I'm outdoing the JL thin sub by a longshot. I digress... dome tweeters can be better than Heils anyday....

Which brings us to dome tweeter materials. Silk dome, great for listening, not great for producing. They're flabby and don't translate those highs well. Metallic domes are better for monitoring, but can be harsh to your ears if you don't use the right type of alloys. As a result tweeters are not something to skimp on when it comes to a monitor speaker. Dome materials/alloys can get costly, but worth it. Unfortunately, companies would rather save a buck here and there and not do it right. My knowledge breaks down here... breaks down worse than a silk dome tweeter. Katching!

Just as sub placement is critical.. .so is monitor placement. The room dominates the low end. A common room will lift the bottom of a speaker's response by as much as 15dB. Of course this all lends towards speaker placement and even moreso YOUR placement.

My biggest advice... wait until the end of the summer.