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Author Topic: 30hz subs to go with TSW-721's  (Read 10898 times)

Daniel Mock

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30hz subs to go with TSW-721's
« on: May 19, 2011, 01:36:44 pm »

So I have a bunch of Turbosound TSW-721s:
ftp://ftp.turbosound.com/datasheets/legacy_products/tsw721.pdf



Problem is that they only play down to 50hz

Is there some subs that play down to 30hz that would match with TSW-721s well?

Thanks
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Art Welter

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Re: 30hz subs to go with TSW-721's
« Reply #1 on: May 19, 2011, 04:34:56 pm »

So I have a bunch of Turbosound TSW-721s:
ftp://ftp.turbosound.com/datasheets/legacy_products/tsw721.pdf



Problem is that they only play down to 50hz

Is there some subs that play down to 30hz that would match with TSW-721s well?

Thanks
The TSW-721 will require a HP around 45 Hz, while a sub going down to 30 Hz needs a HP around 25 Hz.
A horn loaded sub that goes lower than the TSW-721 will have a longer path length, so the TSW-721 (and the top cabinets) will need a longer delay time to match them, otherwise they will not "play well" together. I can't think of any cabinet with LF extension to 30 Hz that would use similar EQ to the TSW-721, running in parralel mode still would require separate processing for each type of cabinet to sound coherent.
Rather than trying to "match" cabinets, you might think in terms of subs (sub subs?) brought out for the gigs that need the VLF,  crossing them from say 30-60, and the TSW-721 from 60-to wherever upper frequency you run them.

ADR, DSL, McCauly have some big guns to cover the VLF range.








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John Neil

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Re: 30hz subs to go with TSW-721's
« Reply #2 on: May 20, 2011, 10:54:56 pm »

I took a 721 pair and front loaded double 18 to the grassy knoll for measurement.  Phase and magnitude traces were identical within the useful passband ignoring a 2.8 db and 3.1 ms offset. The 18 showed extension to 30 Hz the 21 didn't.

I guess word on the street was that horns a direct radiators couldn't play together...and would look radically different under the microscope.  Maybe i misunderstood.  Others on this forum (especially Art) are far better versed in cabinet design than I, and can perhaps speak to factors at play.  I'm willing to post traces if topic swerve is acceptable.

I've heard that turbo designed these with a minimum block size of six in mind.  I haven't field tested to follow the impact of cluster size on extension.  Word on the street is that bigger blocks gain extension...don't know how much you've tried. The flood system manual diagrams suggest that big means HUGE.  My experience is that useable 40 appears beginning at 4 per side...a very empirical observation based on some hand-waving.  YMMV.
« Last Edit: May 21, 2011, 12:21:36 am by John Neil »
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Jeff Bankston

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Re: 30hz subs to go with TSW-721's
« Reply #3 on: May 21, 2011, 06:03:39 am »

Ciare 18.00SW 20-200 cps. http://www.usspeaker.com/18.htm#Ciare
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Ivan Beaver

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Re: 30hz subs to go with TSW-721's
« Reply #4 on: May 21, 2011, 10:41:34 am »

I took a 721 pair and front loaded double 18 to the grassy knoll for measurement.  Phase and magnitude traces were identical within the useful passband ignoring a 2.8 db and 3.1 ms offset. The 18 showed extension to 30 Hz the 21 didn't.

I guess word on the street was that horns a direct radiators couldn't play together...and would look radically different under the microscope.  Maybe i misunderstood.  Others on this forum (especially Art) are far better versed in cabinet design than I, and can perhaps speak to factors at play.  I'm willing to post traces if topic swerve is acceptable.

I've heard that turbo designed these with a minimum block size of six in mind.  I haven't field tested to follow the impact of cluster size on extension.  Word on the street is that bigger blocks gain extension...don't know how much you've tried. The flood system manual diagrams suggest that big means HUGE.  My experience is that useable 40 appears beginning at 4 per side...a very empirical observation based on some hand-waving.  YMMV.

Do you have those measurements to show?  The phase response should show differences-if the 18" were ported.  Sealed they might be closer.
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Ivan Beaver
Danley Sound Labs

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Ivan Beaver

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Re: 30hz subs to go with TSW-721's
« Reply #5 on: May 21, 2011, 02:35:43 pm »

I've heard that turbo designed these with a minimum block size of six in mind.  I haven't field tested to follow the impact of cluster size on extension.  Word on the street is that bigger blocks gain extension...don't know how much you've tried. The flood system manual diagrams suggest that big means HUGE.  My experience is that useable 40 appears beginning at 4 per side...a very empirical observation based on some hand-waving.  YMMV.
Below is a graph of regular bass horns measured in multiples.  There are 1-2-3 and 4 measured.  The same distance and input voltage was applied to all.

The extension does get a little bit lower (but not as much as some would think).  The response does smooth out (due to the impedance loading of multiple cabinets).

If you look closely at the levels, you will see that in some cases you get more than 6dB when you double the cabinets.  This is due to the impedance loading.

Overall you do get more than 6dB when you double the cabinets.  This has to do with the narrowing of the pattern and getting more directivity due to physical size.

However as you go higher in freq-the coupling effect becomes less than at lower freq.

It is important to understand how much the actual "effects" of multiple cabinets applies.
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Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

chuck clark

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Re: 30hz subs to go with TSW-721's
« Reply #6 on: May 21, 2011, 09:54:40 pm »

Thank you Ivan, for bringing up the importance of the coupling & dispersion effects of multiple stack arrays. It looks like the 721's are relatively flat from 35hz to 50hz in a cluster of 4. Wonder what 6 or 8 looks like. Actually, no, I don't care what they look like. This is because I know what they sound like.
Obviously they don't simpley stop working below 50hz, the horn loaded impedance efficiency just starts to roll off significantly at 50hz. When the face of the cluster = the wavelength being reproduced: moot point, huh?
News bulletin: somebody tell Pink Floyd their low end sucks?! HAHAHA!
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Ivan Beaver

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Re: 30hz subs to go with TSW-721's
« Reply #7 on: May 21, 2011, 10:16:26 pm »

Thank you Ivan, for bringing up the importance of the coupling & dispersion effects of multiple stack arrays. It looks like the 721's are relatively flat from 35hz to 50hz in a cluster of 4. Wonder what 6 or 8 looks like. Actually, no, I don't care what they look like. This is because I know what they sound like.
Obviously they don't simpley stop working below 50hz, the horn loaded impedance efficiency just starts to roll off significantly at 50hz. When the face of the cluster = the wavelength being reproduced: moot point, huh?
News bulletin: somebody tell Pink Floyd their low end sucks?! HAHAHA!
How low a sub goes is only important if the material that is being played through it has those low freq.  If there is not deep freq-then having a sub that goes much lower really doesn't buy you much.

On the other hand-there is a common "argument" that you don't really subs that go below 40Hz. 

However there is a lot of music that HAS freq below 40hz.  And if the artist put those freq in their music, then they intended the audience to hear it.  If the reproduction system cannot reproduce it-at the lvels needed-then it is not doing its job in trasfering the music to the audience.

One of the fun demos we like to do is to play some music that doesn't go very low and then the major thing you hear is the sensitivity difference between the various subs.  But play something that has deep bass and then hear some cabinets that reproduce it-and others simply "leave out" those notes.  Not quite the musical experience the artist intended.

So as usual-the answer is "it depends".
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Ivan Beaver
Danley Sound Labs

PHYSICS- NOT FADS!

chuck clark

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Re: 30hz subs to go with TSW-721's
« Reply #8 on: May 21, 2011, 11:08:24 pm »

Yeah! I like stuff that goes to 30. 40 is great for Kik, but more and more of the new stuff has synth bass that is designed to take advantage of the new super subs, of which the 721's were arguably among the first w/ the 6" voice coils.  I always thought of them as kind of a Cerwin Vega earthquake on steroids. Blocks of 8 -12 of them provide that visceral experience that many are simply hoping to acheive in a smaller cheaper package.  I wish them luck. I  don't think you need to make any apologies for a properly powered stack of 721's. 
Material wise, I started with a copy of the movie "earthquake" and went on thru all the "bass mechanics" CD's, and these days I still enjoy the synth dive in "magic man" by Heart and the intro to "rough boy" by ZZ top. Any of the micromoog bass parts in George Clinton stuff and the intro to "do the Bartman" Fun stuff! (Ok, my age is showing) What ch'all using? Then there's always the good ol sine wave generator. THAT will find the cabinet rattles!! HA!
Chuck
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John Neil

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Re: 30hz subs to go with TSW-721's
« Reply #9 on: May 22, 2011, 05:34:11 pm »

Do you have those measurements to show?  The phase response should show differences-if the 18" were ported.  Sealed they might be closer.

Ivan,

Here it is.  My memory mislead me.  The 18" don't make it to 30.  I should've said "towards 30" rather than "to 30" in my first post.

Extension wasn't the primary focus of these snapped traces.  My goal was to make the 18" and 721 play similarly with a given top box with minimum DSP compensation.  Thus, I was more concerned with the other end of the trace.  Boxes were headed to the truck as I did this, so I didn't have much time to play.

Green is the 721 pair, mouths up.  Blue is the pair of 18" slot ported boxes.  Purple is processor only.  There was a wall behind the cluster, 1/4 wave away at 42 Hz, 1/2 wave away at 85...so not an excellent measurement.

What stands out here? 
« Last Edit: May 22, 2011, 05:37:03 pm by John Neil »
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