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Author Topic: Yamaha DXS 18 subwoofer  (Read 11631 times)

Scott Bolt

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Re: Yamaha DXS 18 subwoofer
« Reply #20 on: June 24, 2016, 09:55:06 pm »

I disagree. I've used both PRX718XLF and the DSR118W in the wild. They've both withstood several hard-hitting rock shows with similar performance IMO. (It's funny to me that most of the nay-sayers are also non-owners.)
Hey Gordon,

Admittedly, I don't own the DSR118's.  I did do a side by side of them with the XLF's in the store though running both single subs clear up to clip.

It is possible that "in the wild" it would have sounded different.

I thought the DSR118's sounded good.  They just didn't punch as hard as the XLF's did to my ears.  YMMV.
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Scott Bolt

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Re: Yamaha DXS 18 subwoofer
« Reply #21 on: June 24, 2016, 09:58:23 pm »

Had a chance to hear these subs today, a pair of the DXS 18's with a single DSR112 sitting on them.

Impressive output.  Definitely worth checking out in the size/weight vs output arena.

This DSR / DXS combo would be easily be my pick in the yammie, JBL, QSC, etc, family of offerings.
Even off axis I liked it better than the others on axis... not that my preferences mean a damn  ;D

I have run my DSR112's in a 1 top over 2 subs combo with the XLF's and found that it is a fairly good match to my ears.  That would suggest that the DXS can hang with (or even possibly eclipse) the PRX718XLF in output.

It is interesting that you thought this rig was as good as the direct radiating subs.  Bandpass subs really get a thrashing in most forums for sound quality.
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Mark Wilkinson

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Re: Yamaha DXS 18 subwoofer
« Reply #22 on: June 26, 2016, 01:23:39 pm »

I have run my DSR112's in a 1 top over 2 subs combo with the XLF's and found that it is a fairly good match to my ears.  That would suggest that the DXS can hang with (or even possibly eclipse) the PRX718XLF in output.

It is interesting that you thought this rig was as good as the direct radiating subs.  Bandpass subs really get a thrashing in most forums for sound quality.

I should carefully listen again to a wider range of material,......... to heed all the bandpass warnings.

All I know for sure, is that they more than held their own in a quick punching contest against KW181 and srx828sp.
Maybe they are a version of the Nexo LS18?   Anybody heard them?

And I guess i should ask what the physics are that make bandpass subs put out only one or two notes...?
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Paul G. OBrien

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Re: Yamaha DXS 18 subwoofer
« Reply #23 on: June 26, 2016, 03:01:32 pm »

And I guess i should ask what the physics are that make bandpass subs put out only one or two notes...?

The bandpass design consists of two chambers with the driver placed in the dividing wall between them, when both chambers are ported this yields a 6th order design that produces a narrow peaked response if both chambers are tuned to the same frequency, but if one chamber is tuned lower the response will be wider but have lower gain above the drivers natural output. In the distant past designers could only utilize drivers that were available and the design was most often used with smaller drivers to get greater output from a relatively small enclosure, but the drivers were seldom optimal for this design so we got classic one note wonders like the Bose BP502. But now designers can get custom drivers with any spec they want so designing a bandpass sub with broad uncolored response that really only has to cover 2 octaves at most for pro audio applications isn't as much of a problem, and it would seem that this is easier to do with an 18" driver too, the displacement of a cone this size means that the enclosure gain doesn't have to be as high so the resulting output is broader and more musical. The Turbo Milan 18b is also a bandpass and it sounded as good as the EV and JBL reflex subs it was lined up with at a showroom demo I got a while back.
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Mark Wilkinson

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Re: Yamaha DXS 18 subwoofer
« Reply #24 on: June 26, 2016, 09:41:13 pm »

The bandpass design consists of two chambers with the driver placed in the dividing wall between them, when both chambers are ported this yields a 6th order design that produces a narrow peaked response if both chambers are tuned to the same frequency, but if one chamber is tuned lower the response will be wider but have lower gain above the drivers natural output. In the distant past designers could only utilize drivers that were available and the design was most often used with smaller drivers to get greater output from a relatively small enclosure, but the drivers were seldom optimal for this design so we got classic one note wonders like the Bose BP502. But now designers can get custom drivers with any spec they want so designing a bandpass sub with broad uncolored response that really only has to cover 2 octaves at most for pro audio applications isn't as much of a problem, and it would seem that this is easier to do with an 18" driver too, the displacement of a cone this size means that the enclosure gain doesn't have to be as high so the resulting output is broader and more musical. The Turbo Milan 18b is also a bandpass and it sounded as good as the EV and JBL reflex subs it was lined up with at a showroom demo I got a while back.

Thanks Paul, very informative. 
Were the older designs 6th order both HP and LP?
If so wow, i see that would be really peaky if stacked to same frequency.
But if new drivers can spread tuning a couple of octaves, bandpass seems like no prob, especially for HP.........
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Paul G. OBrien

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Re: Yamaha DXS 18 subwoofer
« Reply #25 on: June 27, 2016, 09:40:05 am »

Were the older designs 6th order both HP and LP?
There are 4th order, 6th and even 8th order and the higher the order the harder it is to get good results.

The ideal target response for a bandpass would look something like this below, here you can see the gain it produces over a reflex design.



But if the driver isn't optimal this is what you end up with.. a peaky 1 note response even with the chambers tuned to different frequencies..



And even if you have a suitable driver the actual response can have unpredicted response peaks that will require processing, and because the driver is unloaded below and above tuning and because there will be out of band harmonics steep high and low cur filters are also required. In the pic below the red and green lines are predictions and the blue is actual measured response.


« Last Edit: June 27, 2016, 09:42:58 am by Paul G. OBrien »
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Mark Wilkinson

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Re: Yamaha DXS 18 subwoofer
« Reply #26 on: June 27, 2016, 08:33:29 pm »

Thx yet again ,  helpful generous post.

I'm beginning to see why bandpass designs are met with skepticism....
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ProSoundWeb Community

Re: Yamaha DXS 18 subwoofer
« Reply #26 on: June 27, 2016, 08:33:29 pm »


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