# Dayton rs100 question



## Jstslamd (Nov 30, 2010)

I know this is kind of a vague question but, has anyone made or seen a low profile center channel design using this driver. Something along the line of this. 

http://www.scipie.com/projects/ht-cynosure/ht-cynosure01.html


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## fusseli (May 1, 2007)

I have not but it would definitely be doable. Pair up a few of them for higher sensitivity and away it goes.


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## Jstslamd (Nov 30, 2010)

The simple vision in my head was something like 4 8ohm rs 100's and a rs28 tweet in a mmtmm type setup. My first problem is I don't know the first thing about designing a crossover for them nor do I had the testing equipment. I just thought it would probably be a good
Design to go with for people that have natp's or dr k's or one of the other reference designs and dont have enough room to fit a tall center channel under there tv.


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## fusseli (May 1, 2007)

That could probably work, it would be a 3-way or 2.5-way setup instead of the 4-way-ish (2.5.5-way? lol) setup than the Cynosure has. That would also be the limit for direct modelling in PCD, 2 woofers, 2 midranges, 1 tweet in an MMTMM


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## Jstslamd (Nov 30, 2010)

Now all we need is someone to brew up an xover lol. Funny how we're on the same page with little being said.


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## Jstslamd (Nov 30, 2010)

How could I go about finding a way to make an xover for this situation ?


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## Jstslamd (Nov 30, 2010)

Any suggestions ?


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## fusseli (May 1, 2007)

I could probably get to it next week. Have a thesis to defend, among other things, to worry about right now :gulp:

If you could work on a bass alignment in WinISD and figure out a baffle layout for the drivers, that'd be helpfull. Both the baffle and box must be conceptuallized before starting an Xover to keep simulations accurate. To keep size down I'm guessing ~.5cuft vented will have to do even though four RS100s would like something bigger.


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## fusseli (May 1, 2007)

Alrighty then. Using the baffle below and planning for a horizontal MMTMM, driver CTC spacing suggests an Xover point to the tweet at 1500Hz or lower. The outter pair of woofers must cross at 800Hz or lower.










I'll keep you posted :T Zaph has tested the RS100s and the RS28A, so that's gonna make sim-based design really easy and more accurate. A 23"x5.5"x12" sealed and stuffed cab is looking good for an HPF at 80Hz, perfect for a center channel. A little bigger & vented and it can go lower but that's not really necessary.


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## Jstslamd (Nov 30, 2010)

Thanks alot!! Keep me updated.


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## Jstslamd (Nov 30, 2010)

Russ

Wow. I was just flipping through threads on the petech forum and stumbled across the thread started about this center channel design. I didn't know this was going to get so complex. Sorry that I haven't been of much help in the situation as my winisd doesn't operate correctly on my pc for some reason that I can't figure out. It also doesn't help that I'm a tad new to the whole DIY speaker hobby. If there is anything I can do to help the situation please let me know. Again thank you for all of the help and effort your putting into this. 

Jason


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## Jstslamd (Nov 30, 2010)

Is the crossover as simple as it looks (atleast from what I'm getting from the pcd screen shot). Excuse me for my ignorance if I'm making myself sound like an idiot. All I could get from it was just one inductor and one cap for each xover and a resistor alon with the second set of mids. Please correct me I I'm reading this wrong. I'm trying my best to be self taught and learn things my staring at them till I think I can Mae sense of it ( good I wish someone lived in jersey to teach me lol).


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## fusseli (May 1, 2007)

Ya the Xover is that few components. Understanding how the 2.5-way works and how dependent the Xover is on driver spacing is the hardest part to wrap your brain around. 

Here's a new Xover I did for the truncated drivers. Getting the spacing tighter further improves the dispersion. If you have any specific questions, do ask. Sorry but I don't really know where to begin in explaining how and why this Xover will work.



Xover, this is superior to the version a few posts back with the original layout. There may be some improvement from a couple more tweaks but this is buildable (overlay is 30deg off-axis horizontal):


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## Jstslamd (Nov 30, 2010)

There was a bit of a question on how compact the enclosure had to be. In my situation I'm an really only limited by height not so much by length or depth. Would there be a large benefit to going with a ported enclosure instead of sealed ?


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## fusseli (May 1, 2007)

The RS100-4 were happy in a smaller box than the RS100T-8 that I'm now planning around. The enclosure could get shorter if less of a roundover is used, although any roundover smaller will be just for cosmetics with little acoustic benefits. The current plan is for 0.6cuft vented at 65Hz. The baffle could get wider or deeper.

Can you take a picture of where the speaker will be going? Depending on how cramped its surroundings are maybe I will adjust the BSC level. WIll also need to know the final possible dimensions before an Xoveer can be "final."


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## Jstslamd (Nov 30, 2010)

The actual room that this is going to be in isn't built yet. I could take a picture of the stand and give rough estimates on space from wall to wall and how far to the back wall everything will be if that helps.


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## fusseli (May 1, 2007)

Jstslamd said:


> The actual room that this is going to be in isn't built yet. I could take a picture of the stand and give rough estimates on space from wall to wall and how far to the back wall everything will be if that helps.


Sure. THis beaing a 2.5-way I already factored in full 6dB of BSC but it doesn't have to be that way. If it's crowded and the centers baffle is in the same plane as other surfaces (like in a shelf on an entertainment center) then maybe I'd trim off a dB or two.


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## fusseli (May 1, 2007)

Wrapping things up for this version, it's good to go and buildable. Very small changes in construction would be tolerable without need for chaning the Xover, as long as driver layout doesn't change and baffle dimensions don't change much (e.g. could forego the roundover and it would be fine).

Four RS100T-8 in an 24"x5.25"x14.25" of 1/2" mdf makes for cab of 0.75cuft gross volume, two 2.5"x8.5" round ports tune it to about 60Hz. Cabinet walls MUST be lined with acoustic foam. Suitable for any HPF from 100Hz down to 50Hz, will take 45W to exceed xmax which would be in the 100dB+ SPL range, sensitivity of about 85dB/2.83V. Solid "8 ohm" load.

Used reasonable sized coils, solid cores for large values. Specified all poly caps, going to NPEs would trim quite a bit off the price. Xover is the same as the PCD screenshot a couple posts back, with a single tweak to the C10 value.

baffle:









schematic:









parts:


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## Jstslamd (Nov 30, 2010)

That's awesome. That works
Out to be a nice Lil center for not a ton of money at all. I really appreciate all of your time you have given me. Thank you.


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