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Fostex P1000-BH frequency response.  Really only 270 Hz?
Fostex P1000-BH frequency response.  Really only 270 Hz?
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Old 27th June 2020, 07:08 PM   #11
vinylkid58 is offline vinylkid58  Canada
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Originally Posted by canonken View Post
Do you have a link to that plan?
Take a look at the spec sheet I just added.

jeff
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Old 27th June 2020, 07:20 PM   #12
canonken is offline canonken  United States
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Got it, thanks. Looks nice.

I would need the Shrike version (for my driver)?
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Old 27th June 2020, 07:26 PM   #13
planet10 is offline planet10  Canada
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Fostex P1000-BH frequency response.  Really only 270 Hz?
The FF105wk is quite different than FE103En. A new Baby Lab would be required.

FE103 SOL has alignmnets very similar to FF105wk and is quite different than FE103En.

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Old 27th June 2020, 08:24 PM   #14
vinylkid58 is offline vinylkid58  Canada
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Originally Posted by canonken View Post
I would need the Shrike version (for my driver)?
Sorry Ken, as Dave points out, a new design would be required for the 103En.

jeff
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Old 28th June 2020, 08:47 AM   #15
chris661 is offline chris661  United Kingdom
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Originally Posted by planet10 View Post
For maximum bass extention Frugel-Horn Mk3, Sperrin, or a well designed TL.

<snip>

dave
Just FWIW, a sealed box w/EQ will get more LF extension than any of those, but will take a large hit in SPL to get there.

My desktop monitors are flat to 35Hz with 4.5" cones, which requires something like 25dB of boost. The mechanically-limited SPL is 82.5dB at 35Hz at 1m. I sit closer than 1m, though, which puts the maximum SPL up to around 86dB.

For me, tinkering with a new microphone design, 86dB peak is enough, and that would be playing something with lots of bass. Playing acoustic or piano music where there's not much LF content, I can go much louder.

You can play around here: Piston Excursion calculator
To figure out if sealed boxes will get loud enough for you at a given lower cutoff.


The BLHs, TLs, etc will have much higher efficiency in the mid- and upper-bass range than the sealed boxes, of course. They don't have the option to apply LF boost to get the low bass back into shape, though: below their LF cutoff, excursion rises quickly but there's very little output.

An alternative would be a passive-radiator based box, and EQ the result of that. The trick would be to tune the PRs to the lowest desired frequency. The advantage would be mechanical: at the very bottom end, the PRs are doing all the work, which reduces the excursion requirements of the main driver. You'd get a bit more mechanically-limited SPL, which might be useful.

Chris
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Old 28th June 2020, 03:35 PM   #16
canonken is offline canonken  United States
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Thanks!

Chris, being I don't need efficiency (I have a beefy 60x2 W integrated amp driving these, and 1m away if I'm leaning back), maybe I should just block the port/opening on my current cabinets and make then defacto sealed?
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Old 28th June 2020, 08:20 PM   #17
chris661 is offline chris661  United Kingdom
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Sure, give it a go. Remember, you do need EQ to get the LF response into line. Just converting the boxes to sealed will probably lose some bass.

Sealed boxes, IMO, are very compromised in terms of output and efficiency, but their advantages of small size and effectively limitless LF response (ie, it's just SPL limited, rather than due to cabinet tuning) means they're actually quite suitable for this application.

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