New Build CJD (Chris) MTM RS150

[mabrandt]

what receiver did you get?

Onkyo SR706. I had an Onkyo SR503. Big difference.

[savage25xtreme]

Onkyo SR706. I had an Onkyo SR503. Big difference.

I was debating on the 805, but when the 806 came out :evil: I decided to see how the UMC-1 looks when some reviews are out with an UPA-7.

Let us know how the 706 does with RS150s :T

[DeathMonk]

CJD and I've both used the silver plated wire from Apex Jr (link above). Very nice stuff. Solders real easily.

I've also used regular 14ga stranded wire from Home Depot and some real cheap 14ga stranded wire from the Menard's automotive department. I haven't attempted to hear the differences, because I doubt that I can. I pretty much believe that the wire from good wire from Home Depot or where ever will get you ~98% of the way there, and provides the most minor improvement, especially when compared to upgrade drivers or electronics. Use what your budget allows.

I use all 14 ga, because I have a stock pile of it. For the short lengths, it is adequate for woofers and all. Smaller gauge wire is nice for soldering to tweeter terminals and stuff, where you don't want to heat it up. USE DISCONNECTS, DON'T SOLDER TO THE TWEETER, though I've done it.

Damping is something that needs to be experimented with. The 2" foam is what a lot of people use. Try it out. Take some out, add some, add some pillow stuffing, take some out. See what you like. The RS150s seem to be very sensitive to stuffing.

I've used 16 gauge stranded in a couple xovers and it seemed fine.

[---k---]

How is the foam lining the box changed after the cabinet is done? Do you just go in thru the woofer holes? I can see with stuffing, wasn't sure about the sides and how to play with that unless I left one side just screwed on. I was planning on glueing up everything. What does too much stuffing do to the way they sound? A sound neophite needs to know what to listen for.

Stuffing is probably more critical than lining. But who knows with the lining, especially when using 2" think wedge foam. JonW used OC703 for his lining and ended up taking all but just behind the woofer out and said that it made big changes. I haven't played much with lining, just stuffing and found it very finicky. CJD confirmed this to be the case. I'm not sure what CJD uses, maybe some 1" wedge foam that I see he has a stock pile of.

You can probably take it in and out through the woofer hole. JonW hadn't glue his rear on yet, which made it easy for him.

The sound will just be off. You may or may not notice it. With too much in, in can sound muffled. Or, it can sound bright due to the bass being reduce slight and the tweeter overpowering.

Everyone was talking about AcusticStuf stuffing for a while. So I ran out and bought a bag. I put two handfulls in each of the Khan's mids. I then thought it sounded a light bright and harsh. I listened to it that way fro probably two or three weeks, because I thought stuffing was supposed to be good for a sealed box. But then, I decided I had enough and took it out. Much better! You just have to play with it sometimes. Let you're ears judge.

[cjd]

In these boxes the biggest thing is "worrying" about reflections off the sidewall right near the mid-woofers. I use Sonic Barrier about six inches back all along the sides, and then about 3/4lb of polyfill in the back half of the boxes. That's for the ported set.

C

[mabrandt]

Well I lined it yesterday with the 2in stuff. Seems kind of over stuffed. Read where a lot of folks use it, that is why I ordered it. I guess I'll see how it sounds. It seems easy enough to take out.

I got the baffle cut yesterday and will get the crossover done today I hope. Maybe by tommorow I can listen to it and see. I was just looking at some pictures of the finished projects that others have done and noticed something about my baffel cuts. The hole for the tweeter cuts into the very edge of the holes for the woofers. Just slightly. The drivers fit fine. The pictures I have seen show a little bit of distance between the two. If you take the drawings and add up the diameters of the 2 drivers I can only see 1/16" space between the 2 cutouts. There is more than that much on the pictures I saw. Will this be all right to leave the overlap or do I have to adjust my dimensions. I'd hate to have to cut another baffel.

I was under the impression that the drivers came with mounting screws. I guess I assumed wrong. Do you guys just use wood screws or do you use t-nuts. I can't remember how I did my sub.

Mark

[---k---]

Some of what you're seeing in photos is likely tolerances. I'm evidently not to good with measuring, because when I built my In-Khans I had one tweeter touching the mid, one tweeter with like 1/16 of space between them, and one with like 3/16" of space between them. You want them as close as possible, as long as they fit. You don't need to go recutting the baffle if it didn't come out perfectly. I wouldn't recut for anything less than a 1/4" gap between the drivers. Others here are much more perfectionist than I.

Use regular wood screws. Whatever looks nice. Ace Hardware is often a good place to buy them. PE does sell some black screws, that I've used. I've also used drywall screws and some Kreg screws.

[mabrandt]

Good deal then. I can glue the front and rear on when I get home this afternoon. I should be able to get this fored up tomorrow.

I went in and reread the thread and noticed that they talked about the spacing on the first page. Jim was using a bigger baffle. I have the centers right where they should be, it is the flange cutout is a little bigger then spec I suppose. I don't have a plunge router, just a regular one, and it takes a little effort to get it going to cut the flange. Plans call for a 1/16" of a gap between the two drivers. If the edges of the flange cutout touch a little, it should be fine.

Mark

[mabrandt]

Well I got this together this afternoon and it sounds pretty good. I do think something is wrong however. My rerceiver has audyssey to EQ the room. It measures the speakers and chooses a crossover. I ran it twice and it chooses a crrossover of 150HZ. I don't think that is correct. Can someone tell me what I might have done wrong? Could it be that 2" wedge foam? I have just listened to it a little and notice more detail, but that's just a ball game.

I attched a picture. I'll worry about the finish after I get it adjusted.

Thanks.

Mark

[cjd]

Did you try moving the mic slightly and remeasure? Side to side there IS the possibility you got a null of one sort or another. Try moving the speaker out in front of the TV and see if it still has the same recommendation.

That aside, you can ignore it and go with 80Hz right?

C

[mabrandt]

Yes, I measured it from all 6 positions. This is what it comes up with. Sure I can lower it to 80, but then it doesn't put any filters in between 80 and 150. Something is not quite right. I took some foam out and remeasured and it's the same. I double checked my crossover and it looks correct. My old center that this replaced from the same spot came in at 70HZ. This has more clarity than that one, but I think there is something wrong with the mids. I would be welcome to any suggestions on what to look at.

Mark

[---k---]

Check to make sure you have the polarity on the RS150s the same and wired correctly.

If you have a DVD like Avia, you can run one of the frequency sweeps to see for your self if there is a big drop in the bass. realtraps.com used to also have test tones you could download and burn to a CD.

[mabrandt]

Check to make sure you have the polarity on the RS150s the same and wired correctly.

If you have a DVD like Avia, you can run one of the frequency sweeps to see for your self if there is a big drop in the bass. realtraps.com used to also have test tones you could download and burn to a CD.

I checked the polarity. To make sure I'm doing this right I run the Neg from the crossover to the neg of one RS150 and then over to the Neg of the other RS150. Same goes for the pos side. I have my crossovers split into two boards. One for the tweeter and one for the RS150's with duel leads coming from the source. On th tweeter, one side had a red dot, no + or -. I assume that was the + side.

Yes, I have Avia and a bunch of others. Back when I built mu sub I got that to EQ it with a BFD and a SPL meter. Just sold the BFD on Ebay along with the old receiver as the new receiver does it all for you. LOL Tomorrow I'll dig it out and see what's what.

I must admit, it sounds good. Not knock your socks off good, but keep in mind it's mixing with crappy mains and All I have watched is a ball game and Survivor.

Mark

[cjd]

make sure they're actually in parallel and not out of phase?

[mabrandt]

make sure they're actually in parallel and not out of phase?

Being out of phase would make sense for the readings, but I have checked it twice. I suppose one of the terminals could be marked wrong. Maybe I'll reverse one and see what I get. I might also just disconnect one of the mids and see what I get.

Is there anything I can measure with a volt/ohm meter on the crossover that would tell me I have it wired right or a bad component? The only difference from the drawing is that they did not have a 35.00 uF Cap so I used a 20 and a 15 to get there. They are wired in parallel. One other thing I just noticed is the order I have the inductors. The positive side of the drawing goes source, 800 uH and then the 100.uH. I have the 100 first. I didn't really think it matters but you never know.


Mark

[mabrandt]

Double checked everything and all seems correct. I ran Avia sweeps and it drops off just where it should. I even changed it to go lower and it seemed fine. I didn't measure it, but could hear it fine. All this with the sub off.

I reran Ausyssey and it still comes up and wants to crossover this center at 150Hz. I can set it at 80 to use, but you lose your EQ between 80 and 150 then.

Anybody have any ideas?

Mark

[cjd]

Order of components matters very much. You should lay everything out exactly in the order it is in the diagram. Putting the 100mH first means almost no primary slope so you're running the 150's sorta full range, so you may have quite a bit of extra energy in the upper midrange causing Audyssey to "see" these running out of steam earlier than they do.

[mabrandt]

Order of components matters very much. You should lay everything out exactly in the order it is in the diagram. Putting the 100mH first means almost no primary slope so you're running the 150's sorta full range, so you may have quite a bit of extra energy in the upper midrange causing Audyssey to "see" these running out of steam earlier than they do.

I'll make the change and see waht happens. I read elswhere that it didn't matter. I didn't do it on purpose but when I di see it, I didn't bother to change it.

Thanks.

Mark

[---k---]

It doesn't matter which way you wire the inductor, ie it doesn't have a positive or negative. The in can either be the wire on the inside or the outside of the inductor. I'm guessing that is what you saw. BUT, the order that they are laid out matter.

If you post good photos of the crossover, maybe we can check it.

[mabrandt]

No, I had them in the right order. I was using a photograph of someone elses from the original thread and got a little confused. I double checked it all and reran the program. Still 150Hz. I don't think it is the position as the center I had there before always came in at 50Hz.

Does anyone think it is the stupid wedge padding? I'm temepted to take it all out and just use Wal-Mart pillow stuffing.

I'll get a photo up of the crossovers later this evening or in the morning.


Mark

[---k---]

We don't have photos of your wedge foam, so can't say. I doubt it is making that big of an impact. Audassy is pretty good, and if it set your old one at 50 hz, I'm leaning towards something is wired wrong. I've wired mine wrong many times, and it took a long while to figure out because it was just off a very small bit. Hard to say without hearing or seeing.

[mabrandt]

I doubt it's the foam now. I took out a bunch and it got real Tinny Sounding. Like everyone was in side the box. I'll put it back in.

Here's the crossovers. I hope you see something.

Mark

[cjd]

Looks right to me.

I still think it could just be that's where Audyssey thinks this should be crossed - you built sealed? With the on-wall crossover and the amount of space you've got I almost wonder if you need more BSC. We may have mis-oriented your build to the on-wall version.

[mabrandt]

Looks right to me.

I still think it could just be that's where Audyssey thinks this should be crossed - you built sealed? With the on-wall crossover and the amount of space you've got I almost wonder if you need more BSC. We may have mis-oriented your build to the on-wall version.

Yes, It is on wall sealed with the Dayton Tweeter. The exact size that is on your web page. Any easy way to check this?

Mark

[cjd]

If you've got some cardboard or something you could cover up the rest of the shelf so it's like this speaker is mounted in-wall and see if Audyssey thinks differently?

[mabrandt]

If you've got some cardboard or something you could cover up the rest of the shelf so it's like this speaker is mounted in-wall and see if Audyssey thinks differently?

I hadn't thought of that, but what I did do is move it down and put it on a TV tray directly in front of the display butting up to the cabinet. No change.

Let's forget about Audyssey for a while as I think I have a bigger problem. As I'm listening and my ears are adjusting I'm getting a hollow sound. It's like everyone is talking inside a box. I assume this has to do with the padding. I did some research and saw polystuffing might aleviate this. It didn't. My question is this. How should this box be padded. I saw pictures showing them completely lined, others don't even mention it and others just use stuffing. Where is the best palce to pad it and with what? Should it be touching the drivers? I am at a loss here.

Mark

Mark

[mabrandt]

Well, I got most of the boxiness gone. It ended up being that my tweeter was not quite flush, it was slightly indented. I had inteneded on getting it flush after I applied the finish. I didn't think that little bit made a difference. I was surprised by how much it did. There is still some boxiness like tone, but not like it was. I still would appreciate a definitive method to line/pad this particular speaker design.

In researchoing the audyssey thread on AVS forums, it looks like a lot of very expensive center speakers also come in at 150hz. I need to dig a little more. The thread is like a kaziillion pages. Leaving the crossover there makes them sound bad in my opinion. I lower it to 80 and it sounds good.

Thanks again for the input. This has been fun and interesting. By the time I get to the mains, I'll have it down pat. LOL

Mark

[Blazin_Jason]

I'm close to finishing up my rs150 center soon (not on wall though). I will give audyssey a try (onkyo-706) once I have it finished. I lined mine with the 1/2" foam on the sides, top, bottom and the 1" wedge on the rear. Not being done yet I can't help and say what freq it wants to be crossed at.

[mabrandt]

I don't know. I have been listening to this for a little bit. Watched a bluray last night using it. I still have a sound to it I don't like. All I can describe is it's like hollow, tinny, echoey. It's clear, just like I'm listening with a bucket on my head. I pulled out all the foam this morning and relined the box with some fiberglass batting I had. It did'nt make a difference.

Anybody know what makes a speaker sound like that?

Mark

[ThomasW]

It's impossible to diagnose what's going on with a speaker without seeing some frequency response plots.

[Xander]

Words to describe sound are very subjective, but I have a feeling you are getting the exact same effect I was. I built my cjd RS150 center last January and the matching mains last March. It took me about 6 months before I finally got the stuffing/padding right. They now sound amazingly clear and not boxy anymore.

Here's what I did:

3/4 3-layer sonic barrier on the back, sides, top and bottom of the inside of the enclosure. Keep it at least an inch back from the baffle and chamfer the front edges. The 3-layer stuff is also mass loading, so my boxes are ridiculously solid now (they're braced too).

The sonic barrier made a huge difference that everyone could tell. Even a couple of friends of mine who don't have an ear for anything. It killed the boxiness and mellowed the mid-highs so they didn't hurt your ears with rock music anymore. They still have all the detail though.

Now here is where I had to experiment a lot. Try a small handful of loose acousta-stuff in the back of the enclosure behind each mid. Different amounts have different affects on the frequency response.

In my tests I changed the stuffing in one enclosure at a time and compared them side by side with well recorded tracks that I knew well.

[---k---]

Stuffing and lining make very audible but small changes. If it sounds as bad as you're saying, I'm thinking there may be a problem in the crossover or wiring. Or maybe there tweeter is bad.

I don't know. A lot of people have built these and haven't had this much trouble.

[mabrandt]

Stuffing and lining make very audible but small changes. If it sounds as bad as you're saying, I'm thinking there may be a problem in the crossover or wiring. Or maybe there tweeter is bad.

I don't know. A lot of people have built these and haven't had this much trouble.

I think maybe your on to something here. I took all the stuffing out and it sounds pretty much the same, so maybe it's not that. Other than the sound of it, is there any way to test a tweeter and see if it's ok?

[---k---]

I know CJD looked at your crossover photos, but I wanted to make sure so I just went over your crossover photos. They look good. Maybe use a meter to make sure you have continuity across all the parts. Double check your wiring. I was confused by your description earlier, but you said that you had them in parallel, so... But, you should have two red wires coming off your crossover, one to each driver +, and two black wires coming off your crossover, on to each driver -.

You do have the shielded RS28, right?

As far as the tweeter testing goes... no easy way to do it, without measurement gear. The PE Woofer Tester can provide a simple impedance sweep that pick up some issues.

What is your locations? Maybe there is someone close that can help.

[mabrandt]

I know CJD looked at your crossover photos, but I wanted to make sure so I just went over your crossover photos. They look good. Maybe use a meter to make sure you have continuity across all the parts. Double check your wiring. I was confused by your description earlier, but you said that you had them in parallel, so... But, you should have two red wires coming off your crossover, one to each driver +, and two black wires coming off your crossover, on to each driver -. .

Well, I actuially have one set going to one driver and then a set from that driver over to the other.

You do have the shielded RS28, right?.

Yes

What is your locations? Maybe there is someone close that can help.

I am in the Indianapolis area.

[---k---]

Maybe you can get DanN (dlneubec) in Bloomington or JonW in Lafayette to listen to them and give an opinion. Probably your best bet. There are a couple of other guys in your area also that hang out on the PE forum.

[mabrandt]

Well, I'm not sure if I have this figured out or not. I was playing around with this like I have nothing else to do and I layed a cloth over the tweeter while I was doing something else and the boxy sound went away. I go to thinking about it and remembered that I didn't have the proper bit to do a 3/4 in roundover and had only done a 1/2" one. I didn't think it mattered as I was eventually going to cover them with grill covers anayway and was told when I did that I could use felt on the baffel to correct. I went and dug up some felt from an old Chiristmas tree skirt. It might even be wool, it's all scratchy and everything. Cut out a square and laid it over the tweeter and the problem went away. I should have realaized it was something like this yesterday when I made the tweeter flush and got rid of some of it. Now all I need to do I guess is determine a thickness and get it so it sounds it's best.

More playting around. Any tips on felt over tweeters would be appreciated as always.

Mark

[mabrandt]

MultEQ will calculate filters down to the -3 dB point that it finds for each loudspeaker (where it starts to roll off). It won't calculate lower than that because that would mean it would start boosting the speaker beyond its capability at low frequencies. So, yes, in your case MultEQ is finding the -3 dB point at 150 Hz and so it will not correct below that. Keep in mind that it gradually reduces the correction to match the slope of your speaker.

From your description above, it sounds like your main speakers have a big bump near 150 Hz. So, it's better to play those frequencies from the sub. The MultEQ filter there has 8x the resolution and so it will handle that bump even better. Or, it could be that the placement of the sub is such that it doesn't suffer from the big bump at 150 Hz. Why is 150 Hz "obviously too high"? The definition of a proper crossover frequency is the one that best blends the sat and sub.

Back to the Audyssey quirk. Above is a quote from one of the Audyssey designers. I guess I should get out my SPL and see where this center does drop off. I worry that if I leave the crossover at 150 it will change where the sound seems to be coming from.

Any thoughts?

[mabrandt]

Looks right to me.

I still think it could just be that's where Audyssey thinks this should be crossed - you built sealed? With the on-wall crossover and the amount of space you've got I almost wonder if you need more BSC. We may have mis-oriented your build to the on-wall version.

Chris, I think your right. Audyssey wants this crossed at 150Hz. I experimented yesterday putting the speaker in different parts of the room and moving the mic around. While my other speakers would change based on where the mic was, this one always came in at 150Hz. Looking at the specs at PE and the measurments on your web site (which I totally need to learn more about) it looks like these are supposed to start dropping off at 150Hz and that's where Audyssey sets it's crosspoint. My old JBL center was ported. I plugged up the port and measured that and it too came in at 150Hz. With the port open it comes in at 60Hz. I'm pretty sure the reading on the RS150 is what it is because I'm using the sealed version. After all, maybe that is why they are called "150's". However, it sounds so much better if I cross it at 80Hz, so that's where I'm going to leave it for now. I'm debating now whether to build the mains as a ported design and/or build another box and port the center to see what I get. Audyssey is a great feature but if you lower the crossovers your defeating the benefits of it. The Audyssey feature is what prompted me to start building these things to take advantage of the nicer receiver. The reason I built the sealed was I read it would work better if you have a sub and originally, I didn't have the room. Now I do.

Mark

[ThomasW]

Be sure to make the hole in the felt for the dome a square not a circle...

[mabrandt]

Be sure to make the hole in the felt for the dome a square not a circle...

Yes, I will. I have a link to your web page. The article doesn't show actual measurements. How far out from the dome should I set the edges of the square? I was lucky enough to have a Granger Supply right here in town and I'm stopping on the way home and picking up a few different thicknesses.

Mark

[cjd]

Actually, it's just that the data I have starts to fall off at 150Hz. F3 is around 80Hz (or should be) in the sealed version IIRC.

[mabrandt]

Actually, it's just that the data I have starts to fall off at 150Hz. F3 is around 80Hz (or should be) in the sealed version IIRC.

I wonder why Audyssey doesn't see it. You can sure hear it. I must have serious room problems. I got the felt in 2 different sizes. 1/2" and 3/8" . It helps tremendously. I don't hear much of a differnce between the 2 thicknesses. I'm still getting some bad sound and I do think it is from the enclosure. If you look at the picture, it is surronded on all sides by solid wood. I'm going to move it and put it all the way up on top tomorrow and see how it sounds. I have to reinforce the shelf tho as that bridge betwwen the 2 columns wasn't designed to hold any weight. I'll get a couple of door stops and angle it down and see how it sounds.

Mark

[mabrandt]

Well guys, I give up. The problem isn't my room, it's the Audyssey program that makes this speaker sound bad. You turn Audyssy off and it sounds good, but then my sub sounds like crap. I had a BFD running my sub on my old receiver and when I got the new receiver I sold it on Ebay. Not only would the new receiver EQ my sub, but the rest of the speakers too. My whole intent on this project was to intergrate Audyssey better into the room with better speakers and unfortunately, it has had just the opposite effect. The Audyssey filters were the source of the boxy sound. I didn't need to move the speaker or add the felt. I just needed to turn Audyssey off. I did, but I don't like how it makes everything else sound. I got to thinking that maybe because I was doing an on wall version, Audyssey wasn't getting the needed bass because I was using the no BSC crossover. Audyssy will filter out levels but won't add something it hasn't heard. They don't want to ruin someones speakers, so it crosses this one at 150. Fine, but it sounds crappy crossed at 150. Lower it manually to 80 or 90 and it makes them sound like their talking under a tent or in a box. Turn Audyssey off and it sounds pretty good, but the rest of the system suffers. I figured well, I'll change the crossover to the one with the step. I ordered the parts and I did that today and no change. It sounds different sure, but it still crosses them at 150 and if you leave it on, they sound like they are in a box.

I have spent a pretty good chunk of change here, so I'm not sure what I'm going to do. Maybe I'll look at some other designs that can reuse this stuff. We'll see.

Thanks for the help. I wish I had been more successful. Not sure what I did wrong here, but I know it's something I'm missing.

Mark

[---k---]

Maybe you can get DanN (dlneubec) in Bloomington or JonW in Lafayette to listen to them and give an opinion. Probably your best bet. There are a couple of other guys in your area also that hang out on the PE forum.

I'm going to repeat this advice. I think you should post at the PE forum asking to get together with someone in your area for a listen. There are lots of guys within an hour drive of you that can probably help.