MCM Vented Box Speakers by Craig Schmidt When I got involved with single full range drivers, I did what I normally do. I read everything I could find about the subject and as usual I became more confused the more I looked into it. What driver do I choose?! What type of cabinet do I make?! Will it work?! What do I do?!!! So I asked Doctor Gizmo. He said to buy every driver I could get and build every cabinet I could. So I did. My wife saw the Visa bill. She was furious. She threatened divorce. I blamed the Doctor. She demanded to talk to him (via the email). His response was historic. "It is better to have many drivers than many lovers." My wife sat in front of the computer for what seemed an eternity, then she got up and started to leave. Before she got out the door she said, "you better clean up when you're done". Like I said before, isn't she sweet. Almost as a joke I had purchased a set of MCM aluminum coned drivers model #55-1870. They cost 9 dollars each. Hell, even a 10 year old with a paper route could afford them. I decided to finally put them to use. Building cabinets takes a lot of work (but is fun) and I was already working on three others. It was time to try a pair of assembled units. Madisound had the best deal going. For $100.00 you get a set of blank cabs (but the connector cups are pre-cut which is great) in real oak veneer. They are .75 inch particle board with solid oak rounded corners. My wife loved them. (So will yours). I still had to cut the holes and downsize the cab slightly. I had to go from .40 cubic feet to .35 or a little less. The difference was about 87 inches which was filled nicely with bracing. These cabinets are fairly deep (the reverse model is anyway, which is what I bought). They come in wide and narrow fronts, get the narrow units which are marked REV. I decided to use a 2 inch port and put it on the back which worked out fine. I lined the walls with fiberglass. A problem arose installing the driver. MCM's spec sheet called for a cutout of 4.25 inches. This is wrong, for our purposes use 4 and 7/16's. I think what has happened here is that MCM is assuming that this driver is to be mounted on the inside of the cab. The speaker was wired with regular 16 gauge zip. Now for the fun!! The completed speakers where mounted on Target 24 inch sand loaded stands. The drivers were run in for about an hour before I installed them in the cabinets so they were about ready to go. I started out with my 5 watt tube amps. Patty( that's my wife) even sat down to listen to them. We started out with an album by the Cranberrys. Thirty seconds into the cut she says "do you have any other speakers running?" I said no and asked her why. Another historic statement is about to come from my wife. "These speakers have great bass." I was shocked when I realized she was right! This can't be. After all we are talking about a 5 inch driver but the bass was there. The real ass kicker was that the rest of the music sounded good too! It must be a fluke. Time for some jazz guitar. Jimmy Bruno and Joe Beck have an album out called Polarity. If you have not heard them before and like this type of music, please run, don't walk, to your nearest record emporium! The first cut is a little muted but the rest of the album really shines plus there was that excellent bass again. The little MCMs sounded realistic. I have read that people say this driver sounds metallic (whatever that means) at times. I guess you could treat the cone with some elixir if you were concerned about it but I am keeping mine virgin. Next came a disk by a new age/jazz band called Oregon. This is an excellent sounding album, but I ran into a problem here. I tried cranking the speakers up pretty loud. My amp ran out of steam, which is a first. I needed more watts. I hooked up my bargain basement ASUSA 30 watt per channel tube amp. Now I had enough power to play loud but the little drivers are definitely not into high db levels (especially in my 24 by 12 listening room) without smearing the sound. Save your ears and listen at a normal(?) volume level. Probably any good amp will do if you adhere to this suggestion. One area where these speakers really shine is the way the soundstage is presented. They do not beam so you can move around and still get a good image of reality. I like not having to be locked into one position. Enough already! The bottom line is for the money these drivers work very well. Do they have a rise in the bass response? Probably. Do they go out to 20 kHz? Probably not. Do they sound good and were they fun to build? You bet! One note though. Everything is 99 percent perception. If you decide to try these drivers and don't like them, do not blame me. Blame Doctor Gizmo. Top