Dayton RS180 and Morel DMS-30 MT Project

[Sdiver2489]

I have been reading up on speaker building for about 3 months now. I have read through a few books and have at least the basics down pat. I really want to build my own design as I am a student at Purdue University in electrical engineering and have learned about filter design. I think it would be fun, even if its frustrating at times, to put what I know to the test and build a medium cost(in my mind ) MT bookshelf speaker.

I am looking for good bass extension as I have dual 4" kenwoods(HTB-505 for reference) that came with a HTiB that have almost no bass extension on them at all. Because of this I have to cross my sub, which performs adequetly, rather high. This can become annoying when it drones at higher frequencies.

So I looked for a MTM design but decided against it based on the fact that I want near 8 ohms nominal and the gain of a series connection did not seem that major for the increase in cost. I looked at 6"-7" drivers that had to be shielded. A few that came to mind were the Vifa P17, MG18, Hi-Vi M6a/n(can't see much difference between the versions), and the Dayton RS180. The MG18 required a large enclosure and the Dayton looked like such a deal that I decided on that(unless you convince me otherwise).

The tweeter I was looking for something that could cross fairly low with good transient response. my final two contenders were the Seas 27TDFC/TV and the Morel DMS-30. I decided on the morel because it looked TO ME that it could cross a bit lower.

I am no expert on this and my ability to see the little nuances of speaker design might be limited. The way I see it, it would be hard to build a speaker that is worse than what I have. I am not looking for perfection but the closer I can get the better. Any help on this project is much appreciated. I just would like to emphasize that I want this project to be my own, no matter how much trouble I might get myself into.

Sorry about the mistake I made in my previous post. I feel so dumb. Hope I didn't blow my reputation on my first post on these forums . I appreciate the kind responses though. I hope you guys are forgiving ops:

[Dennis H]

Mark K tested the Seas 27TDFC (non TV) and the Morel MDT30. Not exactly the same drivers you're looking at but pretty close. The Seas has clearly lower distortion at 1.5 kHz which is about as high as you should take the RS180. In the pics, the 3 peaks centered on 1.5 kHz are the signal and everything else is distortion. Notice how much higher the distortion garbage is for the Morel.

Mark K's driver test page

[cjd]

Well, the other obvious advantage of the Seas is the fact that there's already tons of support and experience with the RS180/27TDFC combo.

I've used the 27TDFC/TV in my MTM (RS150). Great tweeter.

So, it may come down to what kind of tools are available to do this design. Full measurement setup? Pick whatever you want. Nothing at all? Stick to items folks may have measurements they can tweak to your baffle dimensions, etc.

C

[JonMarsh]

Sorry about the mistake I made in my previous post. I feel so dumb. Hope I didn't blow my reputation on my first post on these forums . I appreciate the kind responses though. I hope you guys are forgiving ops:

Don't worry at all- and welcome to HT Guide. There's a wide mix of us here, from college students to retirees. All interested in getting the most out of their next DIY project...

Chris brings up a good point- while it's fun to pick something different, or new, sometimes if you're just getting started, going with something for which a lot of data and experience exists, and an equivalent support network, makes it more likely you'll wind up with the reuslts you want, as well as getting your first experience under your bet. Generally, that means doing a good two way system with robust but not too expensive drivers.

I was pretty crazy when I started in this; my third project, back in 1973, was a Klone of the AR-LST.



But when you try to run before walking, it increases the chances of tripping and falling down... I was lucky that time.

One of the things a lot of us have been doing more of the last couple of years is intensive driver investigations, particularly going beyond just frequency response measurements. Factors like linear distortion (time domain, ETC plots) and non-linear distortion as well as dispersion and frequency response play large roles in perceived driver quality. There's some guys frequenting the guide from time to time like Mark K and Eric Eva who have extensive test experience, or who are gifted with insight into driver construction trade-offs and how improved performance can be realized. A lot of good reading, in other words.

Nonetheless, I wouldn't let that deter you from trying to build the system YOU want with the driver's you're most interested in. I'd encorage you to participate in DIY meets, also, so you can meet with other practitioners, and get exposed to the capabilities which various design approaches bring forth.

Just be warned it can be like becoming an artist; just becuse you have a few pictures hanging on the wall, (or speakers in the living room), you may not feel in the mood to stop creating...

Like the Cheese steak shop I frequent warns, "May Become Habit Forming".


~Jon

[Sdiver2489]

Hehe thanks guys. I was wondering, has anyone here had any experience with the Vifa MG line? If I went for the Seas instead of the morel I could up the budget for the woofer a bit

[cjd]

Hehe thanks guys. I was wondering, has anyone here had any experience with the Vifa MG line? If I went for the Seas instead of the morel I could up the budget for the woofer a bit

You might not gain much at all. Given the company the Dayton RS drivers run with, you'd have to find a healthy amount of extra dough...

No experience with the Vifa's here though.

C

[Dennis H]

Here's a short thread about the MG22. I'm guessing the fiberglass cones will be easier to work with than aluminum ones but, either way, you will need measuring gear and simulation software to get it right.

http://www.madisound.com/cgi-bin/discuss.cgi?read=337367

[Dennis H]

I was pretty crazy when I started in this; my third project, back in 1973, was a Klone of the AR-LST.

Ditto on the crazy part. Same era, my first was a Jensen kit from Allied Electronics. My second was a Klipschorn Klone - and that was when I was a college student and didn't know which end of a Skilsaw to hold onto.

[JonMarsh]

Klipschorn Klone- Whoa Moma! Then you'll appreciate that my SECOND project was a set of Altec Lansing A7 Klones, with Altec drivers and crossovers, including the backside kerfed and bent throat mouth, build with an el cheapo Craftsman Radial Arm saw and a saber saw!

I used the larger 500Hz horns, too, not the wimpy 800 Hz ones.

[denverdoc]

Thanks Jon for the trip down memory lane--my first good speakers were the LST's, enjoyed them for almost a decade but finally got sick of replacing the tweeters!
John S