# Small Two-way monitor DIY



## Guest (Dec 4, 2007)

Hello all powerful and knowing DIY'ers
I will open debate on my next project
Under $500 for drivers and crossovers...I hope WELL under! 

I currently have a pair of Parts Express .25 speaker cabinets and I'm looking for a kit or driver combo to fill them up. 
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=302-707
They are currently being used with (and don't laugh) some Infinity Reference car audio separates. I said don't laugh! If your not familiar, the PE has a replaceable front baffle so I had the car speakers and needed some tunes.
What I'm looking for is a DIY that has been proven to sound nice and not cost an arm and a leg..and one that the crossover is both easy to solder and easy to order as I have no Idea when it come to Crossovers. Or if anyone could make it from designs that would be great too. 

Speakers I've come to like to give you an idea are
Proac
B&W Nautilus 
Focal
Energy Veritas
They will be used in a Home Theater setting but I would say 70% music played, they do not have to be efficient, I will have a dedicated amp on them. 
They will be used with a sub so I'm not concerned with the extreme low end. 
Type of music I listen to is too wide to list...but from Hard Industrial (Ministry, NiN, Marlyn Manson) to Jazz and female vocals. 
I'm aware of Parts Express and Midisound but there are just sooo many choices..I would love some input. 

Thanks


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## F1 fan (Jul 6, 2006)

Check out Zaph's site you may see something there to your liking.http://www.zaphaudio.com/ This is his newest design but it appears your box is a bit to small for it. http://www.zaphaudio.com/SR71.html 

Here also is a few others worth checking.

http://www.rjbaudio.com/projects.html 

http://www.humblehomemadehifi.com/ 

http://www.troelsgravesen.dk/Diy_Loudspeaker_Projects.htm


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## jackfish (Dec 27, 2006)

Why not the Encore from the Parts Express Project Showcase?
http://www.partsexpress.com/projectshowcase/encore/index.cfm


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## Guest (Dec 4, 2007)

Those look just about perfect, has anyone built or listened to them? Also....Crossover...umm...I can solder a little how hard would something like that be?


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## jackfish (Dec 27, 2006)

It should be fairly straightforward to layout his crossover on the appropriate board - http://www.partsexpress.com/webpage.cfm?&Webpage_ID=3&CAT_ID=48&ObjectGroup_ID=197&SO=2 - just tally the capacitors, resistors and and inductors and get a board that will accommodate them. Then its just a matter of wiring and soldering. I haven't heard the Encore build, but have heard the same drivers in a ported enclosure and was favorably impressed.


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## Guest (Dec 4, 2007)

Because i'm a newbie I have questions. I'm looking at the Zaph audio SR71 kit from Madisound.. I know they are designed for a larger cabinet, what would I miss give/ up if I use them with my .25 cabinet? I'm sure some low end but that's ok, I'm going to be using a Sub. I like the thought the crossovers already completed.


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## jackfish (Dec 27, 2006)

You are looking at half of the volume that was determined to be needed for those drivers. I would not be optimistic about good sonic quality using half the volume as called for. Perhaps you could find some electronics students at the local high school or technical college to build your crossovers? It is not a very difficult build schematic.

You could also forgo the Encore crossover and buy a pre-built one at about the same crossover point. This one would work and provide adequate performance - http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-142


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## brent_s (Feb 26, 2007)

hifibuyguy said:


> Because i'm a newbie I have questions. I'm looking at the Zaph audio SR71 kit from Madisound.. I know they are designed for a larger cabinet, what would I miss give/ up if I use them with my .25 cabinet? I'm sure some low end but that's ok, I'm going to be using a Sub. I like the thought the crossovers already completed.


In addition to the cabinet volume shaping the woofer's low frequency response, the crossover is optimized for the baffle's dimensions. Use of a different width or height baffle will change the fequency response of the design...given the subjective nature of judging sound quality, you might actually prefer the change, but the point is it won't sound or measure like John's design.

-Brent


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## 1Michael (Nov 2, 2006)

How about this one? I'm buiding it now. http://htguide.com/forum/showthread.php4?t=13969


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## Guest (Dec 5, 2007)

Isn't that a MTM design? I already have the .25 parts express box.


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## JCD (Apr 20, 2006)

hifibuyguy said:


> Crossover...umm...I can solder a little how hard would something like that be?


I think you've already been getting some good advice, so I'll just comment on this one -- I took a look at the crossover schematic. It looks about as easy as you can get. If you're unsure about the layout, you can do what I did -- post a pic of the pieces laid out on the board before you solder and get some input. 

I would recommend against a pre-built crossover unless it has the exact resisters, caps, etc as the one in the design. There is too much driver intereaction to get everything right with a pre-built crossover usually.

JCD


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## Guest (Dec 6, 2007)

Thanks for all the help and info, I will probably give the Encore and the crossover a shot. It won't be until after the holidays though. 

Thanks


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## starguy (Dec 11, 2007)

A few months ago I got the bug to build a portable 5.1 system, something I can haul to my friend's cabin or to the local town hall to show a documentary or two. I ran across a company called Electro-Mavin ( www.mavin.com ) and bought some Boston Acoustics 4.5" woofers ( 2 for $15 ), some Sanyo tweeters (2 for $9.95) and some Cerwin-Vega crossovers ($9.95 a pair). After digging around on the web I built some ported enclosures out of 1/2" Baltic Birch for the sides, 3/4" Baltic for the back, and 3/4" MDF for the fronts.

The surrounds have 1 woofer & 1 tweeter each and the center has 2 woofers & 1 tweeter. I picked up a used 8" Infinity PS-8 on eBay. I'm using a Panasonic 7.1 digital receiver with them.

I am absolutely amazed at how good this system sounds. So are my friends. Very good reproduction and good range. I've heard much more expensive system that don't sound nearly as good! I'll post some pics when I get a chance.


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## jackfish (Dec 27, 2006)

How are those crossover matched to the drivers and enclosures?


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## starguy (Dec 11, 2007)

Here's the specs on the Boston Acoustic 4 1/2" woofers:

1" or 25mm voice coil 
4 ohms 
SPL 96dB at 1 watt at 1 meter 
Response 55Hz to 7KHz. 
Magnet type standard Ferrite 
60 watts free air power rating 

Here's the specs on the Samsung tweeters:

1" or 25mm voice coil 
8 ohms 
SPL 95dB at 1 watt at 1 meter 
Response 2.5K to 20KHz. 
Magnet type standard Ferrite 
Square Black Plastice Face 
20 watts free air power rating

And here's specs on the Cerwin-Vega crossovers:

Rated to 125 watts, 8 ohms 
Cross Over Point is near 3500 Hz (Use with a 4-8 inch woofer) 
12 db Slope 
Spring Clip Terminals for connecting the speaker wires. 
2.375 by 3 inch opening, 3.250 by 4 inch frame 

So the cross over point is pretty much right in the center of the overlap of the two speakers which seems to work pretty well.


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## Guest (Dec 11, 2007)

I found another kit that looks pretty easy..sealed design, simple crossover..plus it looks like my .25 cabinet will work..

http://www.partsexpress.com/projectshowcase/sc51/index.cfm


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## 1Michael (Nov 2, 2006)

The design of an enclosure is done after the drivers are chosen and crossover is designed. Not the other way around, unless quality is not a consideration. Check out these Proven designs.
http://htguide.com/forum/forumdisplay.php4?f=39
No need to reinvent the wheel:T


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