New project, some questions

Let the fun begin

Well I finally placed the order for my drivers yesterday. I couldn't believe it when I looked back and had sent an email a more than a year earlier saying I was about to order them!

I'm getting 4 X Morel MW144's and 2 X morel DMS37's , plan is to make two MTM's and sit them on top of (eventually) new cabinets for my 2 X Vifa M26WR-09-08 10" woofers.

At this stage I'm thinking about a passive 1st order crossover on the morels, and active on the woofer / MTM. I'm also thinking of being a bit unconventional and crossing the woofers at about 200 Hz so they won't be subs, sort of like a hybrid active/passive 3 way.

I wish I had never heard of baffle step!!!! I'm tempted to just ignore it and hope for the best, but don't think that is a terribly good approach.

Main problem I'm having at the moment (with the baffle step), is that since I'm planning on having separate cabinets for the Woofers, I'm not sure whether I should try and match the baffle step for the woofer and MTM by having the same width cabinets (would mean wider cabinets that I would like on the MTM). I'm just worrying that it may complicate things excessively if I have two different baffle step curves due to the different cabinet widths.

Using the Edge (thanks Svante) If I go with an extremely narrow (280mm) baffle for the woofers (yeah I know) and a 200mm baffle for the MTM’s the difference at 200Hz is only a bit over 1db (woofer ~1db higher than MTM), and the woofer is already down almost 3db at that point. My gut feeling is that if I did this could I safely ignore baffle step compensation on the woofers and only worry about it on the MTM’s…… does that sound reasonable, construction issues aside 😉
If I go with a low order active crossover for the woofer/MTM, could I simply set the gain on the woofers amp a bit higher and do away with the baffle step completely??

Curve 1 in the attached picture is the curve for the woofer with 280mm wide baffle, the other is for MTM with 200mm wide baffle.

Tony.

proximity of drivers to cabinet walls

OK, I thought maybe I better start thinking about the cabinets a bit more seriously than I had already. The plan is to have partitions in the box to separate the two midbass drivers from the tweeter. I've drawn up a rough sketch....

the walls will be 25mm MDF but they look a little thicker as I have allowed for 6mm sound deadening material as well. What I'm wondering is whether having the drivers so close to cabinet walls is a bad thing. I'm going for a narrow cabinet for imaging, and also trying to get the midbass drivers as close to the tweeters as possible.... I'm thinking maybe I should reduce the partitions to 18mm MDF to get the tweeter a little closer to the midbass drivers.

any comments welcome 🙂

Tony.

Thanks Dave 🙂 nice to know I'm not going completely insane 😉 I guess experimentation is the key!!!

I'm thinking I might still need some bsc on the MTM but I'm planning on having an extrenal Xover (for the passive bit) so adding it later won't be a problem if I can't do it all actively.

Time to dust off my old 10W amp and see if it will do for experimenting, or I'm going to be working on an amp project too (which will have to happen soon anyway)!!

Tony.

PS. decided to attach a pic of the drivers

edit: and yes I am going to build new cabinets for the woofers!!!!!!!