My RS180 MTM Design

[fastbike1]

Re: My RS180 MTM Design

Did we not see some of the build before? I seem to think so. Anyway, nice work on the cabs.

Well...after forever, I've finally gotten around to starting this build as a cc. I'm building it to match the theme of my un-named all active mains (pics). I'll do a quick couple of photos and post them in the Project Gallery section when they are complete. Thanks again, Jeff.. for the design and your assistance with some questions a while back.
[ATTACH=CONFIG]27992[/ATTACH]

[cwad8505]

Re: My RS180 MTM Design

Yes on the mains.. nothing on the cc, yet. Was just giving a reference to what they'll have the theme of. I need to head over to the other post and update it... Assembly is complete of the mains (poor man's strads variation).

[fastbike1]

Re: My RS180 MTM Design

Yesssss. That's what I remembered. Still nice cabs.

Yes on the mains.. nothing on the cc, yet. Was just giving a reference to what they'll have the theme of. I need to head over to the other post and update it... Assembly is complete of the mains (poor man's strads variation).

[Thomas Brown]

Re: My RS180 MTM Design

Hey Jeff, If myself or someone else was willing to send you a box/drivers or one of the PE kits that has the RS28A, would you be willing to 'redo' (for lack of a better word) this design for use with the RS28A. since the RS28AS has gone away and is really tough to find used.

It is such a great design, I would love (and by the looks of the responses, so would others) be able to have access to build it without any compromises to your work.

Thank you

[Jeff B.]

Re: My RS180 MTM Design

Hey Jeff, If myself or someone else was willing to send you a box/drivers or one of the PE kits that has the RS28A, would you be willing to 'redo' (for lack of a better word) this design for use with the RS28A. since the RS28AS has gone away and is really tough to find used.

It is such a great design, I would love (and by the looks of the responses, so would others) be able to have access to build it without any compromises to your work.

Thank you

I thought it was in this thread, but it's been a long time and I haven't looked through here to find it - but I thought it had been tested an established that the two tweeters were in reality much closer than originally believed and that the regular RS28a would work fine. I believe it was Paul Carmody who posted the overlaid response of both to show how close they were. I can't really make the comparison you mentioned without having at the very least, one of each kind of tweeter, and I don not have the "s" version at this time.

Jeff

[Thomas Brown]

Re: My RS180 MTM Design

Thanks Jeff,

I have been over the thread quite a few times, Pete S said yes to drop in for RS28A.
The thread just seems to bounce around a little bit (not bad, and not bashing the thread).
Then there is a few that say no to the drop-in of the RS28A.
My main intention of asking is so that the end result (if/when built) they are correct. Rule #1 - Don't mess with a Jeff B. design, Rule #2 - Don't mess with a Jeff B. design (the pixies - where is my mind, is on in the background - made me think of Fight Club - the movie.)

I thought it was in this thread, but it's been a long time and I haven't looked through here to find it - but I thought it had been tested an established that the two tweeters were in reality much closer than originally believed and that the regular RS28a would work fine. I believe it was Paul Carmody who posted the overlaid response of both to show how close they were. I can't really make the comparison you mentioned without having at the very least, one of each kind of tweeter, and I don not have the "s" version at this time.

Jeff

[Thomas Brown]

Re: My RS180 MTM Design

Kinda amazing what one can find with a little search (I am completely being sarcastic, and only directed at myself).

http://techtalk.parts-express.com/showthread.php?225030-RS28AS-vs-RS28A-interesting-finding

[Jeff B.]

Re: My RS180 MTM Design

Kinda amazing what one can find with a little search (I am completely being sarcastic, and only directed at myself).

http://techtalk.parts-express.com/sh...esting-finding

Thanks for finding that. I think you should be good with the non-shielded tweeter based on Paul's measurements.

[cwad8505]

Re: My RS180 MTM Design

Thought I'd share a couple of completed photos of my cc of this design. Keep in mind, I'm no photographer and these photos were taken with my phone. Very pleased thus far but haven't got a ton of listening time in. Thanks for the design, Jeff!! I would have posted a build thread, however, I forgot to stop and take pictures along the way. 3/4 MDF with a Latex in satin black finish. Baffle is wrapped in the faux carbon fiber fabric and countersunk into the face to match the mains I should have set up for too awfully long.

[ontariomaximus]

Re: My RS180 MTM Design

Nice job!

[JCC]

Re: My RS180 MTM Design

Where did you get that carbon fiber fabric. I like that.

[6thplanet]

Re: My RS180 MTM Design

Which tweeter did you use and did you use the original crossover design? Also assuming you used the RS180-8's in parallel?

[6thplanet]

Re: My RS180 MTM Design

So cwad8505...which mids and tweeter did you end up using?

[Nassander]

Re: My RS180 MTM Design

After several months of listening, here are my thoughts.

I did build this as my "reference" vs my own buildings.

First of all i have to say, that Jeff has done beautiful job. Mid range is as good as it can be from RS180. Tweeter is eh, tweeter. I have to say that i don't like this dayton very much. It's ok at least. Upper end shine is completely missing. Cymbals doesn't sound right. It reminds me of seas 27TBFCG/G.

Listenability with some bad recordings is decent.
Anyway this gives me good example of voicing loudspeaker. Rooms are so different.

[pick]

Re: My RS180 MTM Design

I just read this thread yesterday, and I am very interested. I am working on an MTM design using the RS190S-8. I designed a crossover that provides good response for $60. The woofer portion of the circuit is shown below.

I was initially concerned that, while this circuit nicely provides 4th order LR acoustic response, it does not provide as much attenuation of the breakup modes as I would like. A picture of the woofer response is shown below.

First, let me note that there is no baffle step compensation. This design is intended for in-wall use, and my measurement data was collected using a large baffle. The breakup modes around 10kHz are slightly less than 40dB down from the tweeter response. I keep wondering if this is good enough. I built the circuit and listened to some test tones. At normal levels, the woofer response near 10kHz is greatly attenuated but still audible. When I plug in the tweeter, it is much louder than woofer output at this frequency. I kind of think that woofer output 40dB down from the tweeter level should not cause too much noticeable trouble.
The reason this thread caught my eye is because of the simplicity of Jeff's woofer circuit considering the high frequency response of the raw driver. I noticed that the original response plots were scaled to show the response only above 70dB. If I scale my plot this way, I do not see the woofer response at 10kHz. I modeled Jeff's circuit (using Jeff's tools, thanks Jeff). The picture below shows the response of Jeff's circuit on the same scale as mine. Based on the positive response to Jeff's design, I assume my final result will be acceptable.

I would love to hear some opinions on the matter. Thanks in advance.