WTB - cab freq range down to 30hz

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noplanb
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Re: WTB - cab freq range down to 30hz

Post by noplanb » 13 Feb 2018, 20:12

Yes 28Hz has -10dB
http://www.ampeg.com/products/classic/svt410hlf/
The -3dB is the standard to compare low frequencies, and the SVT-410HLF is -3dB at 48Hz. So its not bad, but it is possible to go cleanly lower with other drivers.
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Tim
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Re: WTB - cab freq range down to 30hz

Post by Tim » 13 Feb 2018, 20:47

It doesn't matter if it does 30Hz at -3dB or even 25Hz at -3dB on paper or in real life. If it can't produce those frequencies above 100dB it will not be very useful.

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noplanb
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Re: WTB - cab freq range down to 30hz

Post by noplanb » 13 Feb 2018, 22:19

can't produce those frequencies above 100dB it will not be very useful.
Not sure I follow you.
Things like '100dB' are usually used to specify a sound intensity corresponding to a test condition including 1W @ 1m.
So across the reproducing range of a speaker the 'average' level will be 100dB (say).
At the extremities are where the level drops off - at the bottom end, the point corresponding to 3dB down from the average level, is chosen as the measurement point 'f3'; so in fact, for a 100dB capable speaker, its (lower) f3 point will be 97dB.
We hear the 3dB loss at that point as a slight loss of bottom end, depending what frequency that the 3dB point occurs at.
So something with 10dB loss will be really missing! ie, it will be at 90dB compared to 100dB of the majority of the signal. So, yes, it is hardly worth considering, yet manufacturers insist on trying to tempt us with -10dB values as though they meant more than they actually do.
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Petebass
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Re: WTB - cab freq range down to 30hz

Post by Petebass » 13 Feb 2018, 23:28

I think what Tim is trying to say is that producing those low frequencies is pointless if you can't get them loud enough to compete in a band situation (nominally 100dB).

Car audio and HiFi subs can hit 30Hz without too much trouble. My DIY home theatre SUB is -3dB at 30Hz. Sounds great at home, but would never even come close to cutting it in a live band situation.
* 2 Stingray 5's (one heavily modded), Ibanez SR805, Ashbory, + more...
* Carvin B1500, Epifani PS1000, Ashdown Superfly amps.
* Lots of DIY neo/lightweight cabs including one made from composites http://www.ozbassforum.com/viewtopic.php?f=5&t=2546

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noplanb
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Re: WTB - cab freq range down to 30hz

Post by noplanb » 14 Feb 2018, 08:55

Ah yes - that makes the point that neo-type speakers generally don't seem to have parameters that lend themselves to achieving true -3dB at 30Hz or less.
It is completely possible to get 99dB, f3=30Hz, 8ohm, 650W thermal, but using Ferrite magnet - its an Eminence Sigma Pro 18A-2 in a 350L(!) box.
It also has box tuned at 30Hz, which is above fs of 25Hz. (It will also need a coil to roll off above 900Hz, as it has a 5 dB hump from 900 to 2k). So this one ticks all the boxes for 'true' 30Hz in a live band siuation - except - it's huge! No free lunch.
(The CB15 15 Ferrite I quoted earlier also comes close to that in 330L)
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Petebass
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Re: WTB - cab freq range down to 30hz

Post by Petebass » 14 Feb 2018, 10:08

I expecting Bill Fitzmaurice to chime in here soon. Horns have a unique characteristic whereby combining more than one has the same effect as increasing the size of the horn mouth. This actually increases the frequency range. The bigger the horn mouth, the lower they go. And because they are a high efficiency design, they are capable of band volumes.

Not the sort of thing you can easily walk into a store and buy though, and not the easiest DIY either. Some are easier than others to build depending on the design, none are as easy as building a wooden rectangle.
* 2 Stingray 5's (one heavily modded), Ibanez SR805, Ashbory, + more...
* Carvin B1500, Epifani PS1000, Ashdown Superfly amps.
* Lots of DIY neo/lightweight cabs including one made from composites http://www.ozbassforum.com/viewtopic.php?f=5&t=2546

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noplanb
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Re: WTB - cab freq range down to 30hz

Post by noplanb » 14 Feb 2018, 10:27

Horn
8/ 8| aaah.....
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AB3
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Re: WTB - cab freq range down to 30hz

Post by AB3 » 14 Feb 2018, 14:14

check Lorantz Cabs out,, a friend of mine plays for a dub band and wanted to get down super low with his cab so he got this guy to make him one. http://www.sgraudio.com/about_us.html

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noplanb
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Re: WTB - cab freq range down to 30hz

Post by noplanb » 14 Feb 2018, 15:45

I've looked at Lorantz parameters a lot over the years, and I'd be surprised if SGR did a design that actually achieved an f3 of 40hz or better in a reasonable sized cab. Sad to say, I've found Eminence have some drivers with better-suited parameters for that.
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Tim
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Re: WTB - cab freq range down to 30hz

Post by Tim » 14 Feb 2018, 20:46

@petebass is correct, I was referring to nominal/peak spl outout and not frequency response or sensitivity.

Tell me more petebass, my home theatre setup involves a pair of 15" PSA drivers in sealed boxes, driven by a minidsp and Peavey IPR 3000 amp. It gets down to single digit Hz at the -3dB point.

All this aside, the above setup wouldn't suit a live or PA or anything with a room larger than 25m2

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SneakyJak
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Re: WTB - cab freq range down to 30hz

Post by SneakyJak » 22 Feb 2018, 15:20

Schroeder 18L has happily filled my immediate need but I’m re-inspired to build my own cab with the Fane driver.

I could think of worse rigs

Image

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Imaidan
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Re: WTB - cab freq range down to 30hz

Post by Imaidan » 22 Feb 2018, 19:09

I know you've just settled on the Schroeder but I think there's an unlisted Greenboy 18sub design I've seen pop up on the Greenboy facebook group. Seems to be made by the authorised builders but unlisted anywhere else. Using the Eminence Kilomax 18.
If anything will get you there that would. Or if you're looking to DIY, you could look at building the 15sub which definitely has plans available.
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Petebass
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Re: WTB - cab freq range down to 30hz

Post by Petebass » 22 Feb 2018, 19:49

The cab is 90 degrees out of phase!
* 2 Stingray 5's (one heavily modded), Ibanez SR805, Ashbory, + more...
* Carvin B1500, Epifani PS1000, Ashdown Superfly amps.
* Lots of DIY neo/lightweight cabs including one made from composites http://www.ozbassforum.com/viewtopic.php?f=5&t=2546

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SneakyJak
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Re: WTB - cab freq range down to 30hz

Post by SneakyJak » 23 Feb 2018, 08:24

Petebass wrote:
22 Feb 2018, 19:49
The cab is 90 degrees out of phase!
? If you are referring to the other cab in the picture it’s not plugged in ...

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SneakyJak
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Re: WTB - cab freq range down to 30hz

Post by SneakyJak » 23 Feb 2018, 08:25

Unless that’s a joke in which case ... I’m an idiot

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