Mark Audio CHR-70 Application Thread

[Henkjan]

so, over the easter weekend I completed my small mini monitors with the CHR70.

they are 4 liter sealed, using a high pass capacitor (680uF) to both extend the low end and to flatten the low response (normally in 4 liters sealed there would be a hump). I have applied a notch filter (47uF, 0.39mH, 2.7ohm) as bsc.

the cabinets are made from black MDF and have 3 coats of clear varnish only. I liked the look of this black MDF so much, that I decided to name them "Black Beauty" (I just read this book to my joungest as bed time reading)

[Henkjan]

here is the plan, mdf is 16mm thick

[Henkjan]

the sound is realy good, stil plenty of low, and the high (after some experimenting with the toe in) is very nice, not as sharp as with other metal cones is this price bracket. not as nice as the Alpairs, but they are near double the price so was not expecting that either.

I made some quick *) measurements using Arta of the final result, not bad at all I'd say


*) this was the first project that I used Arta, so in time it was not that quick, I spent most of the day setting up the program, fiddling the (also new) soundcard, and testing the combination, but once that was done, the measurement went prety quick

[italynstylion]

I didn't realize there was black MDF!

<---Jealous!

[italynstylion]

Originally posted by planet10


Shall we start a pool for when they do get finished... i'm in for early 2010.

dave

lol, I actually don't have the option to be lazy. These are for a friend as a wedding gift so I can't leave them unfinished. They aren't as top heavy as I thought they would be. On carpet they kinda are but on a hard floor they might be ok without a base. Eliminating the top void/ballast would help too IMO.

[Henkjan]

Originally posted by italynstylion
I didn't realize there was black MDF!

you'll probably will have to source it from a pro wood shop or furniture maker, since I don't expect your local hardware will have anything else than the normal medium quality stuff (at least that's the case over here)

[Scottmoose]

Certainly is around here. I don't know any UK suppliers that have it, although I'm sure there will be some. Don't worry though -from the samples I've seen, it will still burn just as well as the cheap stuff. (sorry, couldn't resist.)

[italynstylion]

Henkjan, those look very very nice. I might have to check around for some of that black MDF at a specialty lumber yard. Most of the stuff I make I end up painting black so it would be nice to skip a step!

[italynstylion]

I finished the Lotus BVR's this morning after I went and got some screws that would fit the drivers' mounting holes. After some quick wiring they were finished.


The first word or sound that comes to mind is WOW
These things are just unreal! I've only listened to them for about 10 minutes but I'm blown away. First, before I ramble on about these things I should let you know what I have to compare them to. My usual setup for a long time was a set of HSU research book shelf speakers with a pair of peerless XXLS 12's. Now I've been getting used to the frugal horns that I built last month with some of dave's modified FE126 drivers.

I'm using the Lotus BVR plan that Scott and Dave created and I'm running a pair of drivers in each cabinet. I've got the driver in the front baffle a half basket up and the driver on the side a half basket down. The driver on the side of the cabinet is about 3.5" at it's center from the front baffle face.

First thing I noticed from the moment I lit them up was the bass response. Ignoring the fact that it's even there in the first place, the second surprise is that it's beautiful....no other word to describe it. Much better low end than the frugals that I have. I don't think I have the frugals set up very well in terms of room placement (don't have a choice) and that hurts them I think. But since the vents on the lotus design fire forward, at the listener, it seems to work great even in a poorly set up room. The drivers don't move very much for the amount of low end they are providing.

I have the drivers on the sides pointed towards the center of the sound stage at the moment. I plan to play with their direction by swapping the cabinets left to right and seeing how they differ. At the moment I'm kinda running out of space in my room though so it will have to wait till I move some stuff.


PS: Dave, that rasp you told me to buy a while back came in handy during the build. Thank you.

PPS: Scott, the front baffle is 5" wide on the interior piece of wood. The driver's flange is 4.88" wide. What is left at the edges is a paper thin piece of wood. It's so close it's ridiculous.

[HareBrained]

Originally posted by italynstylion
I finished the Lotus BVR's this morning after I went and got some screws that would fit the drivers' mounting holes. After some quick wiring they were finished.

Told ya ...

Originally posted by italynstylion
The first word or sound that comes to mind is WOW

Again, told ya ...

Just wait until they break in. The minor irregularities you hear now will disappear.

Henkjan, those are nice. I've been toying with the idea building a small sealed enclosure because a friend wants some surrounds and they'd be great for that. I'm a little surprised at the amount of rise high end. I can't say that I hear that in mine.