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I have a pair of RS150 shielded drivers and am not sure which MT bookshelf design to build. Was looking for opinions on "RS150MT" with Seas TDFC tweeter posted on this site and The "Encore" design posted on Parts Express project showcase using the RS28 tweeter. I am also open to any other designs floating around that I might not be aware of. I had planned on building them sealed in 0.25 Cuft cabinets, as they will be used with a powered subwoofer. I will be using them for 50/50 music and home theatre and they will sit on wall shelves(close to wall). Thanks in advance for any advice or opinions.
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With bookshelf placement you'll likely want a crossover design with modified BSC, that you can't get with the Encore project unless someone reverse engineers it for you.
IB subwoofer FAQ page
"Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson -
Another consideration would be the amplifier you have. Some of the designs are 4 ohms and if your amp won't handle a 4 ohm load, you will have built speakers that you can't use.
My 2 centsComment
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There aren't many amps/receivers that won't do a 4ohm load into a reasonable volume level. Unless your going to try and listen to the speaker at 110dB more then likely you won't have a problem.Comment
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Thomas,
The Encore is a reduced baffle step design for close to wall placement.Comment
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GEBrown,
Most MT designs are 6-8 ohm speakers.Comment
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I'm not sure if you're interested, but I'll be designing a bookshelf TM using the RS150 and the Vifa DX19 (available at Madisound, Meniscus) in the next month or so. The box will be slightly bigger, about .375 cu ft. But it is intended to sit on a bookshelf (hence, reduced baffle step), and just be a general-purpose, pleasing-sounding speaker. It will be slot ported out the front, with an F3 somewhere between 45-50 Hz. It will also be amplifier-friendly, since I'm designing these for a relative who does not have any sort of fancy amplification. Does that sound like the kind of thing you'd be interested in?Originally posted by Michael Murray
Yes, I CAN do a version with a Seas 27TXXX tweeter, since I have those around, but everyone's done that. I want to try something different. Plus, I like the look (and dispersion) of these little Vifas.Comment
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Undefinition,
My current speaker I'm using is a small Vifa 2-way, which uses a 5" mid and Vifa D27 tweeter. I am looking to try something different, so would like to use Seas 27 or PE RS28 tweeter.Comment
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...now that I think of it...
Do you intend for this to be ported or sealed?
I currently have an RS150 and Seas 27TBFC/G mounted in a .25 cu foot box. baffle width of 8". It's currently ported out the back (of course, making it sealed is an easy fix). Since it's already built, I guess it wouldn't be too hard to measure and design a reduced BSC XO for it.
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If you're wondering, "Why does he have a pre-built box with drivers in it?" Well, it was originally for Jeff Bagby's Dreydels, which is a nice project, but no longer suits my needs. Now they sit on a shelf, waiting for something to do.Comment
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Undefinition,
I am planning on building it sealed using the trans-lam method and birch plywood. I need a shielded tweeter, since I'm still using a wide screen CRT TV. Any chance your Seas 27TBFC/G is shielded?Comment
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No no no, you guys are all nuts.
The RS150 project to build is the Khanspires!
Somewhere in the Accomplished section is a thread with a number of TM designs I'd posted up once ages ago as well. Another option would be Jeff B's Dreydel.Last edited by cjd; 13 May 2008, 19:53 Tuesday.diVine Sound - my DIY speaker designs at diVine AudioComment
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Yeah, those Khanspires make a pretty sound! He should build the room around them.Originally posted by cjdThe RS150 project to build is the Khanspires!
Somewhere in the Accomplished section is a thread with a number of TM designs I'd posted up once ages ago as well. Another option would be Jeff B's Draedel.
Jeff's Dreydels are well-engineered. I used them for a while, and was quite impressed. I don't know how they'd sound as a "bookshelf" (eg: actually on a bookshelf, close to a wall), since they're rear-ported and Jeff built in a mild hump around 100 Hz to give them a "bigger" sound. It does work. As for that thread with the RS150 designs, it's definitely worth a look around, Michael, but to say it gets confusing is an understatement. Even Chris isn't sure what he designed in there :W
Technically, I do not think the TBFC/G is shielded--however I did use them in a pair of bookshelf speakers I kept near my monitor at work. Unless you have them shoved RIGHT against your CRT, they shouldn't be a problem.
On the other hand, the Seas 27T--C are all very close in specs. As far as I know, Seas intended for them to be "drop-in replacements" for one another. I have swapped the TDFC for the TBFC/G and the balance of the system remained the same (though the silk domes have a slight rising top end that the metal domes don't). I have not tried the TDFC/TV, but I think it's within a dB of the TDFC. Chris could probably chime in on this... I trust his knowledge of the Seas tweeters.Comment
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If you are going to do an MT it's the Dreydels or this RS150 ribbon combo. Check about 1/3 of the way down the page at this link.
RS150-8/B&G NEO3PDR
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Oh yes, that is a good design. Scott S really gave me a run for my money at Iowa with that one! He really just "got everything right" there. I was amazed that they had such a big sound, and really effortlessly played through every transient. (Not to beat a dead horse, but the BG Neo3 is not technically a ribbon, but a planar.) I think after Iowa, everyone was thinking, "Geez, I gotta build a pair of those!"Originally posted by Turn2
Sorry to muddy the waters so much, Michael! By the way, I think I'm just going to go ahead and do a crossover for a sealed version of the RS150 and Seas 27T---, since I have the cabinet sitting here, and it's fun practice.Comment
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Yup, you're right. My bad.Originally posted by Undefinition
Good design though.Comment
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I almost pointed that out but then decided to keep my mouth shut :BComment
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The rs150 runs out of linear cone excursion at around 99db. peak in a sealed box of this size.Comment
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I don't know very much about the BG Neo3. How is the off axis of it? I was under the assumption that it was very directional and changes greatly by just standing up from your seating area. My speakers are used for background music 5 channel, seated 2-channel Hi-Fi music, and 5 channel home theatre. I keep coming back to the shielded Seas TDFC tweeter. Maybe the Dreydels in a sealed 0.25 cuft cabinet are my best option at this point. I was hoping someone had heard the Encore's from PE showcase and comment on them. Thanks for all your help and I'm still undecided.Comment
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I'm using the Neo3PDR in my speakers and it's an amazing tweeter. I think maybe the off axis response could be a little limited compared to a regular dome but not by much. I would definately build the RS150/Neo3 design if I was in your situation. :T
Besides, if you have kids they're poke-safe... :BComment
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I am the designer of the RS150-Neo3PDR. Tjese are a couple of things to keep in mind if you build it....
1. It was designed with about 5 dB of BSC - probably a little too much for a close-wall placement. If you built it into a sealed box of at least 0.25 cu. ft., you might get away with it - but it probably would be less-than-optimal. I could simulate something with less bsc...
2. The faceplates on the Neos are huge - almost as big as the RS150. You would be hard-pressed to fit both drivers on the front baffle of a 0.25 cu. ft. box. The design was done with an 8" baffle width and was voiced using a 0.375 cu. ft. ported enclosure.Keep an open mind, but don't let your brain fall out...
https://sites.google.com/view/sehlin...solutions/homeComment
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Thanks Mudjock for your comments, I think the best thing at this point is the RS150+Seas 27TDFC shielded tweeter. I'm sure I will be happy with them, and they will be much better than my Vifa 2-way that I am currently using. Thanks for all the input and comments. Now to just find the time to build them.Comment
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I'm about to rebuild a system using RS150 in sealed .25 cuft. Would you be so kind as to describe your crossover design a little more? I am anything but an expert and these discussions get complicated fast, but yours seems more straightforward than others I read about. It didn't need any notch filter?Originally posted by Mudjock
Mine will be against wall / around HDTV . so far I am considering XO at 1000hz to dome mids i already have), possibly LR-4; but very open to other ideasComment
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As promised
I was waiting for the paint to dry on another project, and since I already had the cabinet built, I gave it a shot. I measured the drivers in a 7 L cabinet, sealed, pushed against the wall. (The dip you see at 2.5 KHz is a diffraction artifact because of nearby furniture (hey, I wanted this to be realistic!)) I then took the measurements into PCD and tried several different topologies.
This is definitely the simplest one (I may post the other ones in a few days). At first glance, I know most will think that such a simple crossover isn't possible on the RS150, but it works. The 2nd order filter gets the breakup mode out of the way, and it just isn't an issue off-axis (and since I voiced these to be set up on an actual bookshelf, that is, against a wall, chances are, the speakers will not be toed-in.
What was a much more significant issue to deal with was the shoutiness between 1 and 2 K. Adjusting the inductor on the low pass for a few days while listening to lots and lots of music, I finally tweaked it to a very "pleasant" sound. I really focused on the midrange in this, and wanted it to sound right on jazz and acoustic music; I mostly left bass-heavy music out of the rotation while voicing these because I found it distracted me from my goal. In the end, I'm really surprised that speakers shoved against the wall can sound so spacious. Stuff like Diana Krall, Pat Metheny, Nickel Creek, John Scofield, and of course, Jobim, had a pleasant "sweet" sound. My wife and I also just watched a monster movie with them, and we were surprised how clear the midrange was.
So dis me if you will for my engineering methodologies, but I recommend you let your ears be the judge. I figure it's called "Do It Yourself" for a reason: I get to design speakers myself that I like to listen to.
-Paul CarmodyAttached FilesComment
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Yeah, ya know.. the parts list for the one with the Dayton RS28A tweet and this RS150 woofer utilizes 9 components whereas yours uses only 5. I'm sure the difference in sound would be negligible.. well, maybe the only real discernable difference would be the tweeter. Since you can't get Seas at PE, you'd have to order from both places though, causing extra shipping charges. But if you already have the Seas tweet, it's not a bad idea and saves some money.Comment
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Originally posted by Mudjock
Mudjock I'd be interested in seeing a design with slightly less BSC, plus are these designed for the recessed faceplate only? Thanks!Comment
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I have made up my mind about which RS150 MT design to build. For the Left and Right channels it will be CJD's No BSC with Dayton RS28A. For the Center channel it will be CJD'd RS150MTM with No BSC and shielded RS28AS. The decision to use the Dayton RS28A is all the great reviews for it, the build quality, it is on sale for $38.00 right now. Thanks for all your posts. :TComment
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Why not just build an identical CJD-no-BSC MT for the center?Comment
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Because of my space requirements. The center sits on top of the TV, which is inside a cabinet. I only have about 10" of height available. My current MT is laid on it's side now and want to remedy that.Comment
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