DAYTON REFERENCE SUBS

[scotthi]

I would like to build a new sub for HT/ music duties 50% each and would like to try the new Dayton RS subs. The sub would have to be placed behind a couch,& box would be wedge shaped. What box volume would I require using the 12" hifi with a 15" passive radiator? If I did go vented, how long of a port are we talking about? Would the 250 watt or 240 watt amp suffice? Room size is abt 16x14.

Would the sound deteriorate from being fired at the back of the couch?

This would be replacing a 15" 2.8 cube sealed quatro which I was very pleased with but haved moved to new location. Unfortunatly 5.5 cube vented Quatro box would be a little tough to hide.

Any thoughts appreciated.

[Pete Schumacher ®]

> I would like to build a new sub for HT/
> music duties 50% each and would like to try
> the new Dayton RS subs. The sub would have
> to be placed behind a couch,& box would
> be wedge shaped. What box volume would I
> require using the 12" hifi with a
> 15" passive radiator? If I did go
> vented, how long of a port are we talking
> about? Would the 250 watt or 240 watt amp
> suffice? Room size is abt 16x14.

> Would the sound deteriorate from being fired
> at the back of the couch?

> This would be replacing a 15" 2.8 cube
> sealed quatro which I was very pleased with
> but haved moved to new location.
> Unfortunatly 5.5 cube vented Quatro box
> would be a little tough to hide.

> Any thoughts appreciated.

Since it's right behind the couch, you may be able to get away with a sealed box as the sub will impart significant vibration into the frame.

Otherwise, a vented box, 3.5 cubic feet with a 4" diameter port 25" long will get you a tune just below 20Hz and provide an overall system response that is well damped for a musical sound with plenty of impact for HT.

If you use the DVC 15" PR, you'll want to add 700 grams of mass to get the 3.5 cubic feet tuned to 18.5Hz.

[scp53]

Pete, I got a quick question(s)- how do you determine dampening factor? what is it? whats bad/good? does win ISD show it? I understand what it is I guess but all those questions are still blurry to me.

thanks a lot, scp53

[Pete Schumacher ®]

> Pete, I got a quick question(s)- how do you
> determine dampening factor? what is it?
> whats bad/good? does win ISD show it? I
> understand what it is I guess but all those
> questions are still blurry to me.

> thanks a lot, scp53

You can infer damping by the shape of the response at cutoff. Systems that show no overshoot in frequency response are better damped than systems whose response shows a bump above cutoff.

When designing a vented system for small room use (like most home environments), you should take great care to tune the system lower than what maximally flat would give you. What tuning low does is cause the response to begin to roll off sooner, but that roll-off starts at a slower rate similar to a sealed system. The gentle roll-off indicates higher damping.

If you put the RSS315HF into WinISD Pro Alpha and choose the default vented alignment, it gives you 4.5 cf at 20.5Hz. If you then set the box volume to 3.5 and tune to 18, you can see how the curve changes, cuts off earlier with a shallower slope. F10 for the smaller box moves to 14Hz vs 15Hz for the larger box, but the 20Hz output is 3dB less for the smaller box. In most rooms, you have significant room-lift there and the larger box would have quite a bit more boom and would likely have that "sloppy sound" that offends some. Outdoors, that would be a benefit, but not in the confines of an interior room of a home. The overdamped alignment of the smaller box with lower tuning would sound much tighter and cleaner, closer to what a sealed box with similar response would sound like.

I hope that description helps.

[scp53]

Thanks Pete, that seems to help.

BTW, have you personally heard an RS HiFi 10 or 12in? Is this sub one of the cleanest on the market? hope Im not hijacking this thread... scp53

[Pete Schumacher ®]

> Thanks Pete, that seems to help.

> BTW, have you personally heard an RS HiFi 10
> or 12in? Is this sub one of the cleanest on
> the market? hope Im not hijacking this
> thread... scp53

No I haven't, but I've read many outstanding reviews. Not the highest SPL by any means, but very low distortion due to the advanced motor and stiff aluminum cone.

I plan on retrofitting my DPL-12 subs with the RSS315. We're installing a Quad DPL-12 sub system into an HT seating platform at my buddy's house. Since he has a pair of DPL-12 and I have a pair, I'm parting with them and replacing them with a pair of RSS315HF.

They don't have quite the same specs or low end extension the DPLs do, but they are close and will work in the enclosures I have as EBS alignment with 15Hz tune. Should be outstanding.

[cptomes]

> I would like to build a new sub for HT/
> music duties 50% each and would like to try
> the new Dayton RS subs. The sub would have
> to be placed behind a couch,& box would
> be wedge shaped. What box volume would I
> require using the 12" hifi with a
> 15" passive radiator? If I did go
> vented, how long of a port are we talking
> about? Would the 250 watt or 240 watt amp
> suffice? Room size is abt 16x14.

> Would the sound deteriorate from being fired
> at the back of the couch?

> This would be replacing a 15" 2.8 cube
> sealed quatro which I was very pleased with
> but haved moved to new location.
> Unfortunatly 5.5 cube vented Quatro box
> would be a little tough to hide.

> Any thoughts appreciated.

Can't address vented/passive questions for you but I built these for Series II 15" and the PE -794 250W plate amps to go behind my couch.

<A HREF="http://www.icixsound.com/vb/icixnation/images/1330_71.jpg">http://www.icixsound.com/vb/icixnation/images/1330_71.jpg</A>

SQ was not compromised. In fact, sitting within a driver radius of the sub makes room modes essentially not a factor. Stand up off the couch and you have the huge +- >10dB swings in response due to room modes.

I prefer sealed subs with lots of cone area. Enough cone area and displacement and you'll have enough spl capability to throw EQ on the system below F3.

My room is about the same size as yours.

[cptomes]

> No I haven't, but I've read many outstanding
> reviews. Not the highest SPL by any means,
> but very low distortion due to the advanced
> motor and stiff aluminum cone.

> I plan on retrofitting my DPL-12 subs with
> the RSS315. We're installing a Quad DPL-12
> sub system into an HT seating platform at my
> buddy's house. Since he has a pair of DPL-12
> and I have a pair, I'm parting with them and
> replacing them with a pair of RSS315HF.

> They don't have quite the same specs or low
> end extension the DPLs do, but they are
> close and will work in the enclosures I have
> as EBS alignment with 15Hz tune. Should be
> outstanding.

Interesting you have experience with the DPL12. I almost bought a pair instead of the Dayton Series II 15" but Adire scared me off when we bought three Hypex 3-ways and they weren't too customer-friendly with me. I went cheap instead, with the (then new) Dayton Titanic MKIII being the driver intended for those wedges I built. The DPL12 would have gone significantly lower but with less SPL capability. I've been wondering how they would compare in the real world with what I ended up with.

[Pete Schumacher ®]

> Interesting you have experience with the
> DPL12. I almost bought a pair instead of the
> Dayton Series II 15" but Adire scared
> me off when we bought three Hypex 3-ways and
> they weren't too customer-friendly with me.
> I went cheap instead, with the (then new)
> Dayton Titanic MKIII being the driver
> intended for those wedges I built. The DPL12
> would have gone significantly lower but with
> less SPL capability. I've been wondering how
> they would compare in the real world with
> what I ended up with.

The DPL is very clean down low. Super resolution on those low notes. In the right box and tuning, you get 105dB @20Hz, plenty for most folks. I'll tell you this, they will rattle stuff off the walls fairly easily.

Too bad they are out of production. They're beautifully built.