# New MTM: Dayton RS150S + DC25T Titanium



## fusseli (May 1, 2007)

This is a Xover design for some drivers I have laying around from a fomer project, two Dayton RS150S-8 and the 1" Dayton titanium dome, DC25T-8. The baffle on the cab (built 5+ years ago) is 7.5"x24" The box is a little under 1cuft tuned to 45Hz, the speaker is intended for an active HPF to cut low bass since it's in an HT with sub. Should be smooth responding as a ~89.5dB 4 Ohm speaker as long as it's in some kind of room, Xover has ~4dB of BSC integrated into it. 

I had the old Clio responses of either driver from when PE published them, and processed those in the Response Modeller for baffle step and phase extraction then started hacking away in PCD.

Xover achieves ~2.1kHz 4th-order butterworth:
LPF - BR4 @ 1.9kHz w/ Zobel & integral BSC
HPF - BR3 @ 2.3kHz w/: L-pad tweaked to shape tweeter response, LCR comp for resonance mode, "optional" 14kHz notch for the HF breakup mode.



























Going with poly caps, a few air core 18AWG coils with a low DCR P-core to minimize insertion loss on the woofers and a cheaper I-core for the LCR comp. Less than a $50 project since I had a few Xover parts laying around and already have the cab and drivers.


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## mechman (Feb 8, 2007)

Can you build me one?  :T


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## fusseli (May 1, 2007)

*RS150-Ti MTM*

Here's a cost breakdown :

Drivers
(2) RS150-8, $73
(1) DC25T-8, $16

Xover with poly caps, P-core coil to reduce woofer sensitivity loss, and I-cores for big coils

woofer section:
1.0mH P-Core	$9.06
20uF Poly	$5.70
.25mH 18AWG	$4.51
30uF/4 Ohm Zobel	$9.75

tweeter section:
10uF poly $5.88
.33mH 18AWG	$4.30
25uF Poly $7.08
3.7/40 Ohm L-Pad	$2.50
3mH I-Core + 3uF + 
30 Ohm LCR Comp	$14.04
14kHz notch (optional?) ~$6

Total Xover: ~$62.82, would be almost half that price with non-polarized + bypass-caps instead.



mechman said:


> Can you build me one?  :T


Haha, make your own! That's maybe $5-$10 of MDF needed, and then paint or vinyl.


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## fusseli (May 1, 2007)




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## FlashJim (May 6, 2006)

Keep the pics coming.


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## fusseli (May 1, 2007)

In service for center channel duty:




















Yes, the MTM grill is being velcroed on for now


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## fusseli (May 1, 2007)

REW results, 10-3000Hz on radioshack SPL meter:

Looks alright, the rockiness below the few hundred hertz region is explainable in the next graph...










Looks like most of those hilltops match ones seen by my mains, so they must all be room-related.










THX spec of 80Hz LF extension is easily shattered (as expected), the two RS150s play to 40Hz in this alignment. The power handling is low, but the high sensitvity means that it will only require a few watts in the HT to get pretty loud.


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## vann_d (Apr 7, 2009)

How did you come up with that spacing between woofers?


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## Dawg1161 (Mar 12, 2011)

Hello there. i also wonder about the spacing ....I have been led to believe that they will soumd better closer ? But then again i haven't listened to yours...

I built the D-III's according to the design plan...I didn't like the spacing of the drivers so will attempt new enclosures this spring with a closer spacing...(i did contact the designer)


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## fusseli (May 1, 2007)

*Re: New MTM: Dayton RS150S + DC25T Titanium*

Good question on the spacing. I modelled the Xover with minimum spacing, for best panning, and the tweet offset to minimize baffle diffraction ripple, with z offsets assuming flush mounting. I will post a CAD sketch of the plan tomorrow, I have yet to construct this new baffle. The spacing seen in the picture is the "amateur" baffle that was already a part of the cab that I recycled for the project. Even taking its wide spacing into account there isnt a huge impact on FR, so I am not in a big hurry.

Hope that makes sense!


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## Dawg1161 (Mar 12, 2011)

That makes more sense with that info...................
Keep up the good work then and let us know how it turns out.


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## fusseli (May 1, 2007)

Below is the designed baffle. With this spacing and Xover point the vertical panning isn't great, but that's an inheriant disability for most MTMs anyways.


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## vann_d (Apr 7, 2009)

Cool, I'm sure the difference will be subtle audibly but you'll know it's better and that's what counts.


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## Dawg1161 (Mar 12, 2011)

That looks better.


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## fusseli (May 1, 2007)

Finally got around to making the new baffle.


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## fusseli (May 1, 2007)

Finally got a grill made, used 1/2" MDF. Cut the edges as to hopefully reduce diffraction by having rounds and no corners. Inside is 3/8" round routing, outside is 1/4" for aesthetics.











PE grill magnets, 3/8" hole then pressed them in with a c-clamp and dab of glue:









Test fit:


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## Jstslamd (Nov 30, 2010)

If you don't mind revealing your secrets. What did you use to attach the grill cloth to the mdf. I'm in the middle of doing the same thing and yours looks like it turned out great.


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## fusseli (May 1, 2007)

What exactly are you building? Disclaimer for this particular build thread, I have since made significant tweaks to the Xover. The Xover shown a few posts back will work fine but needed fixed due to a mistake I had made in processing of the .frd and .zma files for PCD.


Just use spray adhesive to attach the grill cloth. Don't spray it on the sides or front of the grill, only on the back or inside edge where it won't be seen if it soaks through the cloth. Let the adhesive get tacky while you lay out your cloth a table or bench top. Then go slow and be careful pulling the cloth over the grill making sure there is slight enough tension so the cloth doesn't sag but isn't stretched too tight. Spray adhesive is forgiving enough that if you mess up bad, you can gently remove the cloth, spray new adhesive, and try again.


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## Jstslamd (Nov 30, 2010)

Sorry my post was a bit misleading. I'm not doing this same design I'm just making a grill for a different design and was wondering what was used to attach the grill cloth. I have been putting the Tritrix together and am doing a few finish up touches to it that's all. But thanks for the response.


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## fusseli (May 1, 2007)

Gotcha. Good luck


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## Jstslamd (Nov 30, 2010)

Thanks.


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## fusseli (May 1, 2007)

hope this helps, there are a couple different ways you can do the corners.


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## Jstslamd (Nov 30, 2010)

Thanks I'll try and post a pic of mine for you to approve of.


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## Jstslamd (Nov 30, 2010)

Thanks for the tips!!


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## fusseli (May 1, 2007)

Nice, looks like you took more time on yours. I made this grill to look good on the outside only


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## Jstslamd (Nov 30, 2010)

Let's just say the picture does it justice haha


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## jvinhj240 (Aug 18, 2012)

grill looks good.


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## Jstslamd (Nov 30, 2010)

Thank you.


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