RS180 MTM Build in Oak - Pics

[[email protected]]

Re: RS180 MTM Build in Oak - Pics

I don't want it to get that "plastic" look.
thats why i buff with the grey pad first. try it on a test piece..

[mike price]

Re: RS180 MTM Build in Oak - Pics

Ok so I have the RS28F mounted in the enclosure , and run through the original crossover. This is a nearfield measurement.

[czag]

Re: RS180 MTM Build in Oak - Pics

EDIT: If you still happen to have those models with and without the zobel , would you mind posting them? I havent figured out how to use PCD as of yet , I actually just got Excel installed on my PC , and when I loaded up PCD it freezes up when I try to scroll the page up and down. Not sure if I need an update for Excel or what.......

These were modeled on a PE 1CU. ft. MTM baffle, I believe that is what Jeff used. My horizontal offset is 1.5" and I believe his is 1" so disregard any differences in FR below 5-6Khz as differences in diffraction. You can see that there is almost no difference in Phase response, so it should just drop right in.
Here you go:

RS28AS



RS28F



RS28F w/ zobel



Chris

[mike price]

Re: RS180 MTM Build in Oak - Pics

These were modeled on a PE 1CU. ft. MTM baffle, I believe that is what Jeff used. My horizontal offset is 1.5" and I believe his is 1" so disregard any differences in FR below 5-6Khz as differences in diffraction. You can see that there is almost no difference in Phase response, so it should just drop right in.
Here you go:

RS28AS



RS28F



RS28F w/ zobel



Chris

I see what you're talking about on the model , and it is also evident in my measurement. I have a 2.5uf and a 1ohm resistor on hand , do I put this across the tweeter terminals just like a regular zobel?

[mike price]

Re: RS180 MTM Build in Oak - Pics

I went ahead and put the zobel(2.5uf and 1ohm) , it dropped the top end by about 2 db , here is a screen shot of with and without the zobel overlayed.

[mike price]

Re: RS180 MTM Build in Oak - Pics

I experimented with the 10uf cap value as Jeff suggested , I tried the original 10 , a 12 , and a 13. 12uf yielded the flattest measured result , on axis. I stuck with the 10uf however , to my ear it just sounds best that way. I did implement the zobel as recommended by Czag , thank you for that suggestion , it did tame down the rising response considerably. Here are some screen caps of the measurements with the 3 different value caps 10uf is yellow , 12uf is blue , and 13uf is orange.

[czag]

Re: RS180 MTM Build in Oak - Pics

Right, just a regular zobel. Glad it helped.

Chris

[mike price]

Re: RS180 MTM Build in Oak - Pics

Well after several hours of listening to this setup , I must say it sounds pretty darn good. The only change made to the crossover , was the addition of a zobel , to tame the top end of the RS28-F. The original crossover , which can be found here http://techtalk.parts-express.com/sh...ighlight=rs180 , was designed by Jeff Bagby for the NLA RS28-AS. I wanted to use it with the RS28-F being that I had one on hand , and they're also readily available. I built the cabinets and crossover to spec , wired everything up , and took some measurements , which are posted further up this thread. Jeff had indicated to me in the other thread that substituting the RS28-F for the RS28-AS I may have to increase the size of the first cap in the tweeter circuit slightly to prevent the overall response from having a dip in it , he was correct. The crossover for the RS28-AS called for a 10uf cap , the RS28-F needs a 12uf to yield flat response. However , I A/B'ed the two caps several times and as a personal preference , I stuck with the 10uf cap , it seems I prefer the slight dip , and what I would call a slightly more laid back sound. The top end of the RS28-F did rise considerably though , and per the recommendation of forum member Czag , I added a zobel consisting of a 2.5uf cap and 1ohm resistor , this brought it back down to an acceptable level. This is the only change I found necessary to Jeff bagby's crossover to substitute the RS28-F in the RS28-AS place , I figured a few people might be interested to know this , being that the design sounds great and the crossover is simple, and most importantly the drivers are still available. Time to head out to the shop and permanently install the drivers and crossover in there cabinets , and do some more listening. Pics of the completed project to follow......

[mike price]

Re: RS180 MTM Build in Oak - Pics

I wish my photography skills were better , I was trying to get some decent pictures of the finish on these which actually turned out quite well . Maybe I will try again some other time but these will have to do for now.

[mike price]

Re: RS180 MTM Build in Oak - Pics

I've had these in place in my living room for the past two evenings now , so I've had a chance to do some more listening. I've got to say , these are some surprising little speakers. I expected them to sound very balanced and clean , what I didn't expect was the bass from these little RS180's. I don't know if it's the drivers themselves , the fact that they're in a slightly larger cabinet ,or the fact that I'm hearing a crossover that actually has some BSC for the first time , but I've never heard such great bass from such a small speaker. Overall I'm very happy with the build , and very thankful to Jeff B. for posting his design which is what got me motivated to build them in the first place. Of course , me being a never ending tinkerer , now that I've heard the potential of the Dayton reference line , I'm wondering what a couple of the 225's or 270's are capable of........

[Jeff B.]

Re: RS180 MTM Build in Oak - Pics

I've had these in place in my living room for the past two evenings now , so I've had a chance to do some more listening. I've got to say , these are some surprising little speakers. I expected them to sound very balanced and clean , what I didn't expect was the bass from these little RS180's. I don't know if it's the drivers themselves , the fact that they're in a slightly larger cabinet ,or the fact that I'm hearing a crossover that actually has some BSC for the first time , but I've never heard such great bass from such a small speaker. Overall I'm very happy with the build , and very thankful to Jeff B. for posting his design which is what got me motivated to build them in the first place. Of course , me being a never ending tinkerer , now that I've heard the potential of the Dayton reference line , I'm wondering what a couple of the 225's or 270's are capable of........

I am glad everything worked out and that you are happy with the speakers. That's why I share the things I do - to help other achieve their goals of great sound. Your cabinets look beautiful, and I was personally very happy with the sound of this design, so you should have a real winner there. Enjoy the music.

Jeff B.

[donradick]

Re: RS180 MTM Build in Oak - Pics

I really like your cabinets, with natural wood grain on the front and sides, and flat black on the back. I too, was amazed when I first heard 2 x RS180s rocking the bottom end.

[[email protected]]

Re: RS180 MTM Build in Oak - Pics

i wonder if this design would work well in a floorstading MLTL?

[mike price]

Re: RS180 MTM Build in Oak - Pics

i wonder if this design would work well in a floorstading MLTL?

I'm not very familiar with transmission lines , what do they generally gain over a standard ported alignment? And how do you go about modeling them?

[[email protected]]

Re: RS180 MTM Build in Oak - Pics

you prepare an e-mail with all you ts specs and desired alignment and ask paulk real nice if in his spare time, could he do some modeling for you. he is a generous man with his time.