Thoughts on this design...

[fjhuerta]

I'm thinking about building the slimmest tower speaker I can build.

It will be a 3.5 way, with 2 RS180's on the low end, and a Vifa DQ25 on the top end. The Vifa will allow for a closer distance between midrange and tweeter - I could also use a Seas 27TAFNCG. I'm still designing the baffle, in order to minimise diffractiion. It'll probably end up being a 20 cms x 100 cms x 30 cms tower, sealed.

The midrange driver is still an unknown. I have an RS52 that could very well be used. This would make this speaker similar to Zaph's ZDT. Which is a good thing, I believe.

But I'm considering a slightly different route. Using a W4-1337 or a W3-1335 driver instead. I'd love to use the W3, since I've never used it, and I think I could get a slightly better off-axis response. There are other advantages I'm thinking of - a closer CTC distance betwen the tweeter and the mid (incredibly, the W3 mid is smaller than the RS52) and the possibility of crossing this driver a bit lower than the RS52, with a ~300 - 4 KHz bandwidth (instead of 850 - 3.5 KHz).

I believe the W3 is a better option, but I'd love to hear your thoughts...

[benchtester]

rs52 mounting alternatives

My memory is that the RS52 has pretty good off-axis response.

Here is a thread discussing ways to get around the huge mounting plate problem.

http://techtalk.parts-express.com/showthread.php?t=206100&highlight=jkrutke

P.S. in one of Zaph's posts is this link (showing C-T-C under 3 inches):

http://www.zaphaudio.com/temp/ZD3SC-enclosure-vented.pdf

[dlneubec]

fjhuerta,

I know this is what you typically get from folks (suggesting yet another driver) and sorry for this, but have you considered the Dayton RS100 in and MTM configuration for the mids? They will easily extend lower than the RS52 and plenty high for just about any tweeter. You can get two for the price of one W4-1337. I have not heard them, but I can tell you that their early cousin, the RS90's sound really sweet in the midrange of the SoundRounds. I know I'd like to do a WMTM or WWMTM with them as the mids. They ar only about 84db, IIRC, so it would take two to get decent sensitivity. BTW, I believe that Dayton is comning out with a truncated frame version of the RS100.

[fjhuerta]

Benchtester, I should have been more clear... I'd like to use the W3 because it must have better off-axis response than the W4. I'm sure the RS52 has better off-axis response than either one of those...

Dan, I considered the RS100 early on, but they simply don't have the sensitivity I need. The W3s may not have it, either, but they are a bit more sensitive than the 100s.

[HareBrained]

I've been playing around with a model of the RS100 (both impedances) and the Dayton ND tweeters. Here are some generalities from my experience:

1. The -4 and the S-8 versions are different. Different enclosures and different xo topologies.
2. In an MTM, the S-8 can be used in parallel if you're amp can handle the 3.5 ohm minimum impedance. Net SPL is a respectable 87db. The -4 must be used in series and the SPL is <83db. This meant some "severe" attenuation for the tweeter with the -4.
3. Excursion is an issue below the Fs. Modeling will show a vented enclosure will have an Fb of 50 but the driver will go over the 4mm stoke below 70 Hz. You need to keep the Fb around the Fs (78-84 Hz). A sealed enclosure provides better power handling and an HP xo is recommended for either.
4. If you include BSC (which you will need to), the net bump with the S-8 midrange requires the xo point to be below 3kHz. With the -4, you can go to a little above 4kHz. What that meant for me is that the ND20 tweeters were difficult to use with the S-8, but the ND28 worked fine. The ND20FA worked well with the -4.

I tried to integrate 5 different 5"-7" woofers with the MTM (all single driver configurations) with xo points ranging from 200-500Hz, and they didn't want to play. You can use the -4 MTM with a single driver but the lower xo interacts with the BSC and the upper reaches. The RS180 didn't model too bad but the xo components were kind of "huge", if you know what I mean. Your experience may be different.

My cabinet width was only 5". A wider cabinet might help the BSC issues.

In the end, I think I'll be building an MTM in a sealed enclosure using the S-8 and the ND28, with a 2nd-order on the LP for the RS100s and a 3rd-order on the ND. XO point is ~2500Hz. The sensitivity of the ND is low and doesn't require any padding. My receiver has an 80Hz active xo on the output and I'll be building a pair of TB W6-1139 vented cabinets with a single subwoofer amp driving both. The 80Hz 2nd-order xo modeled well for controlling the excursion. LR4 would have been better but I can work with what I got.

Good luck with you design.

-John

[dawaro]

I'm thinking about building the slimmest tower speaker I can build.

It will be a 3.5 way, with 2 RS180's on the low end, and a Vifa DQ25 on the top end. The Vifa will allow for a closer distance between midrange and tweeter - I could also use a Seas 27TAFNCG. I'm still designing the baffle, in order to minimise diffractiion. It'll probably end up being a 20 cms x 100 cms x 30 cms tower, sealed.

The midrange driver is still an unknown. I have an RS52 that could very well be used. This would make this speaker similar to Zaph's ZDT. Which is a good thing, I believe.

But I'm considering a slightly different route. Using a W4-1337 or a W3-1335 driver instead. I'd love to use the W3, since I've never used it, and I think I could get a slightly better off-axis response. There are other advantages I'm thinking of - a closer CTC distance betwen the tweeter and the mid (incredibly, the W3 mid is smaller than the RS52) and the possibility of crossing this driver a bit lower than the RS52, with a ~300 - 4 KHz bandwidth (instead of 850 - 3.5 KHz).

I believe the W3 is a better option, but I'd love to hear your thoughts...

If you are thinking of a 3.5 way have you seen what Zaph has drawn up?

[fjhuerta]

If you are thinking of a 3.5 way have you seen what Zaph has drawn up?

That... is.. COOL!

Is it a thread here, or where did he post it???

:E

[cjd]

I have a pair of the RS100S-8 on hand to mess with. My pondering is definitely not quite what I've done so far, so I'm going to keep quiet till I discover I actually get around to doing some experimenting (or you know, forgetting I have the drivers and they gather too much dust...) Sensitivity is not a particular goal so the single driver will be fine.

S-8 did not look good solo in a traditional box (vented or sealed) to me. -4 looks much better.

[HareBrained]

I have a pair of the RS100S-8 on hand to mess with. My pondering is definitely not quite what I've done so far, so I'm going to keep quiet till I discover I actually get around to doing some experimenting (or you know, forgetting I have the drivers and they gather too much dust...) Sensitivity is not a particular goal so the single driver will be fine.

S-8 did not look good solo in a traditional box (vented or sealed) to me. -4 looks much better.

Agreed. The models I've done had the -4 much more cooperative then the S-8 when by itself. Those were for surrounds/nearfield (little-to-no bsc) and the results were very encouraging. I'm considering using a set in my car.

I got around to playing with the S-8 MTM in a vented alignment and wider baffle. I found a 7.5" baffle with the drivers 0.75" off-center decreased the step effects very nicely. The net FR afforded a little smoother midrange. The vented alignment resulted in a large bump (3-5db) centered from 90-120 Hz. This is probably due to the high Qts. The impulse response and excursion weren't too bad but it was definitely best with heavy fill. With the 80Hz active xo thrown in, the net output was very similar to sealed enclosure. The -4 models well into a vented enclosure but again, excursion control will offset the gains unless you're willing to keep the power down. The S-8 seems to accept a little more power (better excursion control) than the -4 in similar alignments, enough to have a higher db/W at max power levels (just an observation and not a real consideration as you probably don't want to play around at that hairy edge.)

FYI: I'm using Zaph's data, UniBox for box modeling and Jeff B.'s PCD and RM for BSC and crossover design.

[chrismercurio]

A few thoughts:

Jed posted several slim designs.

Then of course suggesting other drivers (some of which you have used before and may still have):

BG Neo3*, BG Neo8, Seas L16 (from Linkwitz Pluto), and Tymphany LAT

For thin and uncomplicated, your vifa tweeter, the 4" TB titanium woofer instead of the 3", and the LAT. Full (or close to it) bandwidth and really slim.

Last suggestion:

Buy a used pair of NHT 2.9's or 3.3. Those were slim and sounded nice if memory serves.

I didn't think I had that much to say,

Chris

[Brian Bunge]

I was thinking of using a pair of the RS100-4's in a top/bottom mounted bipole surround to hang on the wall in the bedroom and then use 4 of the S-4's in a very slim MMTMM 2.5-way center channel. I'm thinking one of the neo tweeters but haven't looked at them too closely yet. The cabinet would be roughly 24"W x 5"H x 6"D and would sit on top of the center section of the dresser right in front of a 30" LCD. For a subwoofer I'm thinking of something similar to the boogeyman sub to go underneath the bed.

Left and right mains will probably be something similar to RJB's Microbe SE's since I already have the drivers. Maybe I should pick up one of the press fit Seas metal domes for the center....

The crazy thing about all this is that the wife suggested I add surrounds and pretty much greenlighted the whole project!

[fjhuerta]

Thank you all for your ideas! Apparently, everyone is crazy about the Rs-100s. I know I am - it just won't give me the sensitivity I need, with two RS-180's... it falls just a bit short.

I also found out something. I simulated the baffle on the FRD tools Excel spreadsheet, and, if I want something really narrow, while crossing over at 350 Hz or so, the W3 will simply not work. It starts rolling off at around 900 or so Hz with my current cabinet design, so I'll lose even more sensitivity. I'd need to make the baffle wider and taller for this to work.

Since this needs to be a high WAF design, I think the W3 is not useful. A lesson to be learned: finish simulating before hitting the "Order now" button on Parts Express! Nevertheless, I'll definitely be using the W3 later on, somewhere else. Probably on an MTM with a small bass bin.... for now, I think I'll use the RS180, RS52, and DQ25.

[HareBrained]

Javier, the trio of drivers are a fine set. You wont be disappointed.

I don't think everyone is crazy about the RS100's. I think everyone is crazy about all of the RS drivers and these just happen to be the newest.

B.B., the RS100 doesn't come in an S and -4 variety. At least I can't find it listed anywhere.

[Brian Bunge]

B.B., the RS100 doesn't come in an S and -4 variety. At least I can't find it listed anywhere.

Ah, I see. No biggy. I don't need shielding since the TV is an LCD. I just like the way multiple RS100-4's model vs. the -8's.

[fjhuerta]

I just received my W3-1335S drivers.

To say they are the sexiest little drivers I've ever seen is an understatement. They may be the prettiest woofers I've ever seen. Excellent workmanship on them.

Better looking than the W4-1337s!

I need to take some distortion measurements of them... sadly, I have no baffle to mount them on.

[fjhuerta]

The W3s are so gorgeous I've decided I really want to use them in this build.

Since I'm thinking about using them at 300 or so Hz, a .5 design doesn't make much sense. I'd still need to add a bit of BSC to the midrange, and I could never hope to reach the sensitivity of two RS180s with one W3.

I'll probably concentrate on a 3 way instead.

In order to get the widest bandwidth possible out of the W3, I'm considering changing the DQ25 tweeter for a Seas 27TAFN. According to the CTC distance, I could probably get away with a 300 - 4.5 KHz midrange bandwidth. Sweet!