# let surrounds naturally roll off?



## MetropolisLake (Sep 22, 2014)

Just out of curiosity, is it possible to take a pro style small'ish woofer and just run the thing full range on surrounds, basically just let it naturally roll off and not have a tweeter, without it sounding awful?  No crossover, no tweeter, just a woofer that has fairly high extension. Of course that would be stupid on mains but I'm wondering if it is doable on surrounds without it sounding ghetto.


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## Kal Rubinson (Aug 3, 2006)

MetropolisLake said:


> Just out of curiosity, is it possible to take a pro style small'ish woofer and just run the thing full range on surrounds, basically just let it naturally roll off and not have a tweeter, without it sounding awful?  No crossover, no tweeter, just a woofer that has fairly high extension. Of course that would be stupid on mains but I'm wondering if it is doable on surrounds without it sounding ghetto.


I don't know (or care to know) what "sounding ghetto" means but it will probably sound awful unless you are already suffer from presbycusis.


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## MetropolisLake (Sep 22, 2014)

Kal Rubinson said:


> I don't know (or care to know) what "sounding ghetto" means but it will probably sound awful unless you are already suffer from presbycusis.


No I'm suffering from the opposite of that, very high hearing sensitivity in the upper frequencies, much higher than what is considered normal, basically the audiologist's equipment cannot go any lower on volume and I'm still detecting it at 8 kHz. Audiologist basically just told me I need to lower frequencies at 6 kHz and up quite a bit because it's making everything seem super loud and is possibly doing some damage. Going to have to EQ my system quite a bit. Just got me wondering if such a thing as this is possible in lieu of a bunch of EQ.


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## tonyvdb (Sep 5, 2007)

MetropolisLake said:


> just a woofer that has fairly high extension.


A single driver with a wide frequency range is just about impossible. Your not going to get much detail out of a speaker like that. Fairly useless for anything in my opinion.


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## fusseli (May 1, 2007)

Yep it's possible, and can work good enough for light surround duty. It's a very good budget solution for surround sound effects, IMO. I'm actually using the exact thing right now, Dayton ND drivers.


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## MetropolisLake (Sep 22, 2014)

tonyvdb said:


> A single driver with a wide frequency range is just about impossible.


It seems that it is possible, it's just that the cone starts breaking up or something on the top end. SEAS Exotic X1-04 for example can play as low as 30 hz and as high as 20 kHz. The graph starts looking nasty up top though.


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## MetropolisLake (Sep 22, 2014)

fusseli said:


> Yep it's possible, and can work good enough for light surround duty. It's a very good budget solution for surround sound effects, IMO. I'm actually using the exact thing right now, Dayton ND drivers.


I was actually looking at the Acoustic Elegance TD-10M. It extends cleanly to over 2,000 hz and apparently has been measured to almost 7,000 hz, then it starts dropping pretty sharply. It will be beaming on the high end of things but I've just got one row of seats anyway, dispersion doesn't matter all that much. The audiologist said I need to kill frequencies above that anyway, which just made me curious as to if it could work on surrounds, just use one of those.


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## tonyvdb (Sep 5, 2007)

It would be interesting to see a frequency graph of those as my thoughts are the same, I would suspect that they would have a good peak at its mid range and a good fall off even before 2kHz


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## MetropolisLake (Sep 22, 2014)

tonyvdb said:


> It would be interesting to see a frequency graph of those as my thoughts are the same, I would suspect that they would have a good peak at its mid range and a good fall off even before 2kHz


Le on AE drivers is next to nothing, supposedly about the only thing that limits its upper extension in a typical design is the beamy-ness that's inherent in all drivers of a given cone width, also the huge phase plug keeps it going for awhile. They're all supposed to go way higher than usual due to these things.


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## Kal Rubinson (Aug 3, 2006)

MetropolisLake said:


> No I'm suffering from the opposite of that, very high hearing sensitivity in the upper frequencies, much higher than what is considered normal, basically the audiologist's equipment cannot go any lower on volume and I'm still detecting it at 8 kHz. Audiologist basically just told me I need to lower frequencies at 6 kHz and up quite a bit because it's making everything seem super loud and is possibly doing some damage. Going to have to EQ my system quite a bit. Just got me wondering if such a thing as this is possible in lieu of a bunch of EQ.


In that case, you would be better off with relatively full-range speakers and the control of a decent hf filter so that it matches your particular needs.


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## fusseli (May 1, 2007)

The single driver with high extension works great for light surround duty. A single driver lacks the biggest in off-axis response so they will not fill a room the way a good 2-way would. They do however work perfect if aimed directly at the sweet spot you always sit in (me <--). I switched between my Philharmonic AA pair and the single Dayton ND, there is a noticeable difference, but I prefer to use the Daytons for the occasional helicopter or surround effect and use the nicer monitors for hi-fi 2.0 on my computer setup. 

Old Dolby surround only used to go up to 8 kHz (?) for what it's worth.


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## ajinfla (May 10, 2009)

MetropolisLake said:


> Just out of curiosity, is it possible to take a pro style small'ish woofer and just run the thing full range on surrounds, basically just let it naturally roll off


No, the MCH fidelity police will be at your door demanding you install a tweeter.

Actually, one can do anything one pleases, whether it's considered advisable or not. If you don't like it, use a smaller diameter wide range driver or....add a tweeter.

cheers


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## DqMcClain (Sep 16, 2015)

There are plenty of drivers designed to be used alone in an enclosure, and many of them do a reasonable job. HF beaming is an issue (often mitigated by phase plugs), and LF response has multiple issues... usually that better LF response is at the expense of better HF response. 

That said, a few manufacturers make full-range drivers. I have a pair of Dayton PS93-8's, 3 1/2" drivers with paper cones, inverted half-roll surrounds, and big phase plugs, that I have tested full-range open-baffle. They sound pretty good. (They'll be even better when I mate them to the final baffle design and give them some bottom end support from a pair of JBL 2226H's)

I've also used a pair of Dayton PA130-8's in a vented box as a high-output boombox for a specialty application. I used them exactly as you were asking, without a tweeter, and they sound "good enough". They'd sound better with a tweeter, but the design called for output rather than fidelity, a tweeter would have cost me real estate on the baffle I didn't have, and I was trying to keep cost down. When it was all said and done, the PA130's performed beautifully within the design parameters. 

I also have a Roland MicroCube guitar amplifier that I have removed the factory driver from, and replaced it with a Celestion T5687A. It's a neo-motor, 5" paper cone woofer. High sensitivity, and more than enough HF response to cover the harmonic detail coming from a guitar. This same woofer was used in a high-output boombox like above, but with a tweeter... and it sounded better with the tweeter. 

SO... in each case, my experience says this can be done with satisfying results. It almost always sounds better if you give the full range driver some help on either end, but since you're specifically looking for a more mellow HF, you can act according to your design parameters and let the driver roll off on its own. The thing I'd tell you to avoid is buying expensive full-range drivers, as they often go out of their way to give better HF with things like phase plugs and whizzer cones, and that will be contrary to your design goals. 

Check out the Dayton PA130-8. 1) They're cheap. 2) According to the graphs, they're pretty flat through about 1KHz, and break up significantly above 5KHz. If you can mount them such that they're off-axis from the MLP by about 45deg, that might take care of your issue. You'd need to correct the crazy reflections with surface treatments so you don't wind up with HF signal bouncing around the room though. OR, you could always through a low pass filter on them designed for something normally though of as silly, like 6KHz. 

I say give it a shot. What's it going to hurt, other than your schedule and your wallet?


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