DIY Monitors - Yea or Nay?

[Yareek]

No clue where this thread should go, but I'm considering building a pair of 2-way passive monitors due to my inability to find something I like for under $1000. I've got plenty of soldering and audio experience, and after noticing the poor quality of drivers in prosumer nearfields, I figure I could probably put something together that would work.

Hatt Mk III

This is the design I'm looking at. $165 for drivers, $85 for cabinets, $35 for crossover parts, and $50 in stuffing/deadening/posts/cable/etc. So the whole thing would be $350 or so shipped. That will allow me $200 to $300 for a nice power amp as well as treat my room and possibly get a subwoofer down the road.

What I'm looking for is a speaker that's very detailed, reasonably flat and accurate, and non-fatiguing. I've used Seas drivers before (the Excel 7") and was very impressed, and I would prefer the smaller aluminum cone driver because it would have more detail as well as less roll-off in the crossover range.

The tweeter is a metal dome, which looks to be optimal for detailed high end. I noticed that most cheap monitors use silk domes, which roll off too much in the highs for my taste (hearing loss from drumming without earplugs when I was a kid probably). I think this is what will make or break the monitor.

I'm also looking to "build" a mono full-range monitor, akin to the Auratones of old. This Fostex driver and this amp should be a nice "nasty" speaker to A/B against the slightly prettier 2-way.

So am I nuts to try this? I've tried almost everything under $1000 and I don't feel like that would be the best use of my money. I'd rather spend $500 on monitors and $500 on treating my room.

 

[mshilarious]

Hey man, quit stealing my ideas!

I have those tweeters with the cheaper polypro Seas woofer. I think you will be VERY pleased with them. I have a few notes about that design: I don't like the woofer sticking out in front of the tweeter like that, especially as close as it is. I don't think the few extra mms would kill the phase relationship THAT bad.

Also, the crossover design seems a bit fussy to me. Why the three caps in parallel? Surely there is a sufficiently good 10uF cap available?

I have a redesign of my mains pending with larger 10" woofers though, the 6.5"s are destined for an MTM center channel. I am just not satisfied with 6.5" mains + sub, and I don't do the nearfield thing. I would recommend you consider 8"s instead.

I have those Fostex drivers laying around too, just waiting for me to build a cabinet so I have a "consumer" pair of reference speakers/rear surrounds. I actually haven't listened to them, but I've always been pleased with the other Fostex drivers I've owned.

 

[Yareek]

Whew, I'm not nuts

What about this design?

I've got 7" Seas Excels in my car and they play LOW. I'm hearing bass down to 80 Hz, and I don't even have the door panels and Dynamat plugging the holes, meaning they're playing 80 Hz open air

These things will be about 2 to 3 feet away from me, so I don't want huge speakers. My BX8's with 8" aluminum woofers have problems crossing over high due to what I would assume are nasty breakup nodes around and above the crossover frequency. I was thinking of splitting the difference with these drivers which claim a 50% increase in surface area. Even though it's only a half inch claimed increase in diameter, I believe real life measurements would place it closer to an inch, and accounting for the phase plug and surround, 50% increase would be right. That would move a lot more air and increase sensitivity.

BUT, looking at the frequency response, there's a HUGE ring around 7k which would probably require a filter of some kind, unless 24 dB at 2 kHz does the trick. The 4.5" has a smaller peak at 9 kHz which wouldn't require special treatment. Of course I could bump up my budget a bit and go for the Excel 5.5" which has lower mass and inductance but I think it'd be a bit too laid back for monitor work.

I've never designed a passive crossover before (I'm used to working with cars and active stuff), but I have done some electronics mods and repairs dealing with R-C circuits. I figure I'll just steal someone else's design, simplify it, and then tweak until the drivers balance. Kind of like the switches on the back of most monitors, except with 50 cent resistors and caps.

Fostex seems to be the "go to" for full range...and I love the concept of a summed mono single-driver reference. Just sitting in the middle of the desk and yelling at me. I wouldn't be surprised if it's actually nicer than the old Aurotones frequency-wise...and the huge sensitivity of the driver should let me get away with the cheapie T-amp.

Bottom line: do you think these would work well as an alternative to the sub-$1000 crop of nearfields on the market?

 

[mshilarious]

I've got 7" Seas Excels in my car and they play LOW. I'm hearing bass down to 80 Hz, and I don't even have the door panels and Dynamat plugging the holes, meaning they're playing 80 Hz open air

I don't have the Excels, they are pricy for me. The Excel 7"s probably do outperform the lower range Seas 6.5"s. However, 80Hz isn't 40Hz, either. You did mention a sub, so I was just sharing my experience. If you have a reason to suspect you'd want a sub, I'd rethink the size of the mains.

But then:

These things will be about 2 to 3 feet away from me, so I don't want huge speakers.

as I said I don't do nearfields. The nearfield philosophy doesn't make sense to me.

My BX8's with 8" aluminum woofers have problems crossing over high due to what I would assume are nasty breakup nodes around and above the crossover frequency.

I think there is probably a significant difference in the behavior of the higher quality Seas drivers.

Bottom line: do you think these would work well as an alternative to the sub-$1000 crop of nearfields on the market?

Based on the somewhat limited sample of monitors I've heard, yes.

 

[Yareek]

Awesome, thanks for your input man.

I'm REALLY liking Zaph's Seas L18/DBFCG27 design. I think a 7" driver would get low enough that I wouldn't need a sub. And the breakup node of the driver is high enough that it should be taken care of with the crossover (plus the notch filter).

The only thing I'd do is mount them in a .38 cubic foot sealed box instead of .5 cubic foot ported...I don't like ported enclosures and would like a smaller box.

I got the Excel 7" because EVERYONE was recommending them, and I didn't want to compromise in my car. They completely blow away every other woofer I've heard. The aluminum 7" is supposed to be really close with a hair more high end and not quite as flat a response. I figure it will be just fine for my needs (not to mention the room will be somewhat treated and I will be listening on axis, which is big).

Plus I'll always have the ghetto mono speaker!