Using Single full range as a sub [message #20667] |
Sun, 13 February 2005 23:20 ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
lon
Messages: 760 Registered: May 2009
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Illuminati (2nd Degree) |
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I just got the yen to experiment with a subwoofer out on my Yamaha receiver. There's a couple 8 inchers I haven't built Voigt pipes for yet. I'm wondering if I can do a quick and dirty build with one or both. I have the RP U100 book out in front of me, but sure can't see anything about a cutoff frequency or what goes on inside the Yam. Oh yeah, no spec sheet on these 2 Roland 8 inchers either. They were sold as closeouts from Roland pianos on Ebay.
Would it be a waste of time to mount these? Play with isobarik maybe? I'm on my way to do one of Fitz's Tuba 18's eventually.
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Re: Using Single full range as a sub [message #20670 is a reply to message #20669] |
Mon, 14 February 2005 13:26 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
lon
Messages: 760 Registered: May 2009
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Illuminati (2nd Degree) |
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I have a spare box that I can make a front baffle for just to see what the sub output of the little Yamaha would do-- for grins, as we say. In my general ignorance of things, I wanted to try the isobarik technique to get that constant pressure volume mentioned in Ray Alden's book Speakerbuilding 201. But yes, I want to do the Tuba 18 and am enthused about it.
I have never used a sub system before, so this is just daydreaming.
The Roland 8 inchers have pretty small magnets too.
I'm wondering what one of those cheap plate amp subs woudl so in such a rig?
--> The thing I want to avoid at all costs is any sort of rumbling, wall shaking thud that may be a cause for gee-wiz, but sound like shite on music-- in other words, what most people experience as home theatre. :-/
I'm pretty happy with my single driver MLTL boxes using Fostex 127e from a design at Single Driver Forum. It is the best scratch build I've done, but still doing some tuning stuff on those.
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Again, look at the response [message #20671 is a reply to message #20670] |
Mon, 14 February 2005 15:38 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
Gazmo
Messages: 9 Registered: May 2009
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Esquire |
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![](http://www.pcworksplus.com/wertz/tuba/Tuba%2024%20vs%20EVM%202x18%20pink%20no%20xover.JPG)
This is a comparison of a tuba 24 with EV 18 subs. The 18 inchers are shown in blue and the tuba is orange. If you listen to a bass note progression on the EV speaker, you'll hear every note about the same volume level. The tuba hits 40hz and 80hz real loud, but 50hz is 4 times lower than 40hz and about 50 times lower than 100hz(!) In terms of musical notes, this means D(37)and E(41) are blasting, but then F(44) and G(49) are much lower. Notes A(55) through C(65) grow gradually louder and when you hit D(70) again, the sound is getting pretty loud. E(80) is booming one note bass with F(87) and G(98) very loud too. Loudness falls off after that again. In the span of one octave, D(37) to D(70), loudness starts very high then drops to a low and rises to a huge 15dB peak again. I don't know about you, but two huge peaks in a single octave is unacceptable to me. I'm sorry, I just couldn't let this go unnoticed. I don't mean to be a nag but I couldn't remain silent any longer. I was told this site was choosy and quality oriented but then I see tubas with whatever woofer will fit and dr horns with 50 cent knock off piezos. They may be good for garage bands on the cheap but I don't think you can call them hi fidelity.
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Re: Again, look at the response [message #20674 is a reply to message #20673] |
Mon, 14 February 2005 17:00 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
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Wayne Parham
Messages: 18758 Registered: January 2001
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Illuminati (33rd Degree) |
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Bill doesn't sell loudspeakers, he sells plans for loudspeakers. Build quality is up to the people building the cabinets. They can make Brazilian Rosewood cabinets and put JBL Pro or Eminence Magnum woofers inside if they want.Bill's plans are illustrated and detailed. They are good quality plans. Bill is also a sponsor here, paying to support the website and helping to make it possible for us to have this discussion. He gives of his money and time to host his forum here, and to provide support to people building speakers using his plans. I wouldn't call that "cheap." What I think is cheap, is manufacturers of audio products that pop into discussion websites like these for free plugs or to bash their competitors. If an audio kit manufacturer or DIY company doesn't host a support forum, that's cheap. If manufacturers or dealers go into open discussion sites just to plug their products, that's cheap. And if they send in sockpuppets to attack competitors, that's not only cheap but also low. I see a lot of bottom feeders like that popping into various audio discussion forums.
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Re: Using Single full range as a sub [message #20675 is a reply to message #20667] |
Mon, 14 February 2005 18:26 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
GM
Messages: 114 Registered: May 2009
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Viscount |
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Greets! Don't think they'll make it as subs. Courtesy of 'Zene': Fs = 78.76 hz Vas = 24.5 L/0.8652 cu ft Re = 7.309 Le = .2462 mh Qms = 5.772 Qes = 1.977 Qts = 1.473 Sd = 21.4 sq cm/3.317 sq in BL = 0.4477 N/A (calc'd) Spl 89.65 1w/1m Pe = 30W Here's an Alpha TL (end loaded straight pipe) I did for someone, but if they built it they didn't let me know how it performed. Looks good in a sim though: L = 39.25" SO/SL = 166"^2 recommended stuffing density = 26 oz of polyfil GM
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Re: Again, look at the response [message #20676 is a reply to message #20674] |
Tue, 15 February 2005 12:17 ![Go to previous message Go to previous message](/forum/theme/AudioRoundTable/images/up.png) ![Go to next message Go to next message](/forum/theme/AudioRoundTable/images/down.png) |
lon
Messages: 760 Registered: May 2009
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Illuminati (2nd Degree) |
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Well, back on topic, and me being the cheapest of all with no test gear I'm going to start cutting holes in wood and make up a small isobarik.. maybe play it with no mains just see if it is doing anything. Far as I know this will be plug and play and whatever cutoff will be handled by the receiver. With a phono plug connection I'll prob'ly buy a phono plug one end and bare on the other rather than fooling with tinning and such.
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