rs225p vs rss210hf as a woofer

Kornbread

Was demo'ing the little Sadies (xt25+5fe120) for the kin folk then fired up the big 'not a khanspires' for a comparison.  One thing led to another and the rs225p's in the 'naks' bottomed a few times during some heated demos.  They do not bottom gracefully!   

How many times can they bottom until they are finished?

Just looking around and the rss210hf is on sale.  Does anyone have experience in using these as a woofer?  How clean are they?  Do they make a good woofer or are they better at subwoofer only duty?  They will not be called on above ~300hz. and will almost slip in place of the rs225p cutouts.      

Wolf

They are clean to about 850 in my experience, and Dan used the HO in a 2-way to 1kHz. Be ready for the loss in sensitivity though...

dcibel

Most subwoofers with any reasonably low Le motors will work just fine as woofers for <300Hz, however the issue is usually with sensitivity. RSS210HF is a4 ohm woofer with 85.6dB@2.83V sensitivity which might be just fine for an active system, in a passive setup the resulting system sensitivity ends up around 80dB after BSC which isn't too exciting. Not that it "won't work", but you'll have to throw a lot of power at it.

If you are bottoming out a driver, then you are way low on output capability for your SPL needs, the driver hit it's limits several dB below that point. The RSS210HF only has 2mm more xmax, while it likely has more xmech, it really doesn't have any more max SPL capability than the RS225 based on xmax alone, it just digs deeper at the expense of sensitivity. I'd suggest doubling up on your woofers for the 6dB of sensitivity and 6dB of max SPL gain. If the extra 6dB of sensitivity is too much, consider using 2 of the 4 ohm variant in series, which will net you 3dB sensitivity gain compared to the single 8 ohm driver, but still 6dB more max SPL due to double surface area and double power handling.

When shopping for drivers, max SPL can be looked at simply by surface area * xmax. The sensitivity only determines how much power you need to get there.

Wolf

There is no RSS210HF-8 though, so paralleling the HF is not doable unless you have a 2 ohm stable amp.

DanP

As discussed above, I used the RSS210HF (it might have been the HO actually - I can't remember off hand), and it worked quite well crossed at 1.1kHz.  The extremely low sensitivity could be an issue in your design, but it would definitely provide more/better deep bass than the RS225P.

Kornbread

Adding another quad of rs225 will require designing/constructing a completely new speaker and I was down in my back for a couple days after schlepping the current ones around the deck.  Lightbulb ... make it in sections that bolt/clamp/lock together. 

More than likely, the rss210 will be the direction these go.  Since it is an active design, sensitivity will be a mute issue.  Could just wire them series but the amps will drive 2ohm and I think a cone will be an easier load than either the Apogees or the Amazing planars.  When driven at speed for any length of time, the crossovers in the Amazings gets way to hot to touch.  They smell like a heater that just kicked on for the first time.  The amps, yep, they get hot too. 

Think it's time to sim up a pair of rss210 in the current box and see how they look.              

NavyGuy

dcibel said:

Most subwoofers with any reasonably low Le motors will work just fine as woofers for <300Hz, however the issue is usually with sensitivity. RSS210HF is a4 ohm woofer with 85.6dB@2.83V sensitivity which might be just fine for an active system, in a passive setup the resulting system sensitivity ends up around 80dB after BSC which isn't too exciting. Not that it "won't work", but you'll have to throw a lot of power at it.

If you are bottoming out a driver, then you are way low on output capability for your SPL needs, the driver hit it's limits several dB below that point. The RSS210HF only has 2mm more xmax, while it likely has more xmech, it really doesn't have any more max SPL capability than the RS225 based on xmax alone, it just digs deeper at the expense of sensitivity. I'd suggest doubling up on your woofers for the 6dB of sensitivity and 6dB of max SPL gain. If the extra 6dB of sensitivity is too much, consider using 2 of the 4 ohm variant in series, which will net you 3dB sensitivity gain compared to the single 8 ohm driver, but still 6dB more max SPL due to double surface area and double power handling.

When shopping for drivers, max SPL can be looked at simply by surface area * xmax. The sensitivity only determines how much power you need to get there.

The regular RS series do not have as much excursion as listed. Most of the line can be driven into bad behavior and even bottoming out more easily than you would expect. I find the xmax to be off more the larger in diameter you go in the series. The RSS series has much more useable excursion and I would say the xmax rating is more realistic.

jholtz

Hi Kerry,

What is the actual xmax of the RS225 drivers then? They advertise 7mm.

Jim

Wolf

While I agree that the RS series can be driven into unloading behavior fairly easily, I don't believe it's related to less than rated Xmax, but more because the suspension does not damp the motion as well as other drivers.

NavyGuy

jholtz said:

Hi Kerry,

What is the actual xmax of the RS225 drivers then? They advertise 7mm.

Jim

Hey Jim,

I haven't seen the 225 tested but the 180P was in Voice Coil at one point and maxed out at like 3.5 mm IIRC. From what I've heard at events, the 225 seems to bottom out easier. Might be the tuning people are using but that's just what I've experienced. The published xmax rating goes up as the driver size goes up but it seems the reality is the actual xmax is about the same between all.

NavyGuy

Here is the link to the article for the 180P. 3.2 mm Cms limited at 10%, 5 mm limited at 20% distortion criteria. BL is 5.2 and 6.3 mm.

https://audioxpress.com/article/test-bench-dayton-audio-rs180p-8-7-reference-series-midwoofer

NavyGuy

Wolf said:

While I agree that the RS series can be driven into unloading behavior fairly easily, I don't believe it's related to less than rated Xmax, but more because the suspension does not damp the motion as well as other drivers.

My personal opinion is that the Qms seems to indicate that it's something else going on. Don't get me wrong, they are great drivers with very nice distortion for the price but just don't seem to be able to be pushed as hard as some. I actually really enjoy the bass they produce when kept within their limits.

Wolf

low-ish HD provided by an aluminum phase plug and no copper.

jholtz

Thanks for the feedback Kerry. Interesting article about the RS180-P version rather than the aluminum cone version. The motor seems to rate fairly well with them indicating a copper shorting ring and aluminum phase plug and a T shaped pole piece which probably contribute to its low distortion numbers.  That said, I assume most of this applies to the RS225 aluminum versions as well for design.  It indicated a 6.9 mm xmax at 15% distortion which would certainly indicate performance deteriorating as xmax increased and volume going up. However, the RS180's are rated at 6mm vs the 7mm for the RS225's.

Curt and I have been searching for a replacement woofer for future designs that are reasonably priced, perform really well at the volumes I listen to, reasonably available so it's not a one off or close out driver and we can depend on the driver being available in the future. That's been a tough slot to fill without spending a lot more more money for similar or less performance. After hearing Matt's and Javad's designs at Grand Rapids I'm very interested in checking out the Satori 9.5" woofer. More money but excellent performance from what I can see.

While I'm on my availability rant, there won't be a Tymphany driver in anything I'm involved with. The NE149-4 is an excellent driver but now a distributor has to buy 500 in order to get them. Screw Tymphany!

Anyway, thanks for the feedback!

Jim

jholtz

A quick follow up, there have been just a few Statements series speakers that builders have gotten crazy with and ruined one of the RS225's but not very many considering how many have been built. That said, RS225's don't die gracefully. They just bottom out and die.

Jim

Kornbread

Everything is great till it isn't, then they make one hell of a noise when bottoming.  Wish there was a little warning before I go sprinting for the volume knob.     

PaulEbert

I, too, am looking for an excellent woofer, with the WO24 as the current favorite. I wonder how the SDX10 compares (below 300 hz or so).

Wolf

I still say there is no copper in the RS midbasses. I opened up an RS150, and the phase plug was the only 'shorting device' installed.

jr@mac

No copper in the 180, either. I tore one down a few years ago. 

jholtz

So is Audioexpress incorrect then? A running production change possibly?

I don't tear apart drivers that fail, just throw them away or return for warranty. Usually warranty. I do know that based on Curt's measurements, RS225's test very well and sounds really clean. I suspect the WO24 will test better.

Jim

jr@mac

Maybe the -P have a bit of copper, but the shielded and unshielded aluminum cone does not, at least the ones I tore down. T-shaped pole piece, yes. The phase plug is the only shorting ring on those.

Shorting rings are not the only "path" to low distortion, LeX cult notwithstanding.

Wolf

Well- when someone brings a defective driver to a DIY, and you get to tear into it- you do!
I have had several instances where I sent bad resultant measurements of the defective units back to the distributor, and I was allowed to keep the driver for autopsy whilst the new one was sent out. After autopsy- then you throw the unusable portions away. Magnets are always fun!

jholtz

Just to be clear, I wasn't questioning either of your words on anything. I appreciate the feedback and it's another good reason to dump Dayton along with Tymphany.

Honestly, I've become infatuated with SB drivers. I hope the quality and availability continues. I think they're a hell'va driver for the money.

Jim

Wolf

Why not jump on the Scan Discovery wagon, Jim? The (former) XLS and XLSS drivers are really good.

jholtz

Scan Discovery drivers looked like a rerun of Peerless PL drivers from about 15 years ago to me. A lot of people liked them but I never found them to be that impressive. They are of course a subdivision of Tymphany which I'm grumpy with as well.

Thanks for the idea, but I'm exploring SB to see if they fit my needs.

Jim

Tom_S

jholtz said:

While I'm on my availability rant, there won't be a Tymphany driver in anything I'm involved with. The NE149-4 is an excellent driver but now a distributor has to buy 500 in order to get them. Screw Tymphany!

Anyway, thanks for the feedback!

Jim

Is that for any driver or just the NE series?

jholtz

Hi Tom,

I can't answer that. Meniscus told me some time ago that NE149-4 required a 500 piece order. We didn't talk about other drivers. The minimum 500 piece order effectively killed the Finalists which used the 4 ohm version. It seems most distributors do have 8 ohm versions available so designs using them are ok.

Jim

GeoffMillar

jholtz said:

Scan Discovery drivers looked like a rerun of Peerless PL drivers from about 15 years ago to me. A lot of people liked them but I never found them to be that impressive. They are of course a subdivision of Tymphany which I'm grumpy with as well.

Thanks for the idea, but I'm exploring SB to see if they fit my needs.

Jim

Hi Jim

I very rarely manage to bottom out the RS180Ps in Curt's Slapshots, but I have to really try; The Band's 'Up On Cripple Creek' and Sam Brown's 'Box' will do it due to their bass and drum patterns, but the volume is at neighbour annoying levels.  There doesn't seem to be any damage to the woofers.

I rather like the SB16PFC-8 which I've used in a two way speaker with a VIFA BC25TG, it sounds rather nice - not my design, but.  Weird frame shape, but according to SB's web site, the frames will soon be round and much easier to mount.  The PFC series have 'mineral reinforced plastic' frames but they seem strong enough and more robust than the Peerless SDS series of woofers.  I can't afford the Satoris, and the PFCs are a very reasonable price here in Oz. 

I'm considering making a two way with the SB20PFC, which has very similar specs to the RS225, but with slightly less Xmax.  It's A$52 as opposed to A$135 for the RS225, and the (few) reviews I've seen are very complimentary. I have no idea what I'm doing, I don't want to spend too much money!

Geoff

Wolf

Jim- SS is no longer a subsidiary of Tymphany. They bought themselves out a few years ago. Another company purchased them a couple years later, but Tymphany they are not. The reason for the Discovery line was improvement or continuation of the products that were originally made and had tooling for in Denmark that were moved to China under Tymphany.

jholtz

Thanks Wolf! That's good to know.

Jim

PWRRYD

Hi Jim,
Some folks will turn their nose up at using cost effective woofers in a high end design, but I personally don't care what most folks think.  That said I think you should at least consider for a moment the very nice MCM Audio Select 55-5670 woofers.  Tom Scoville and I measured one at DIY Iowa and it measured almost dead nutz to its factory specs.  I purchased four of them, lightly broke them all in and then measured.  They were as consistant as any Dayton, Peerless, or SB Accoustic drivers I have measured.  Use the factory specs and model them in your box program of choice.  I think you and Curt will like what you see.  Disclaimer:  I have not actually built a box yet and listened to them, so I can't comment on how they sound or how they handle being over driven compared to the RS225's.  But two of them for the price of one RS225 in about the same sized enclosure....