Advice on a 15"+ sealed subwoofer design

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Advice on a 15"+ sealed subwoofer design

Hi,
I've been searching the web the last few weeks looking for a design that fits my requirements, but I haven't found what I'm looking for yet. I will be using the sub for both HT and 2ch. stereo. I have no size constraints on the sub, but I want it to be sealed. I'm also planning to use active equalization to extend the low frequency response.
I would like to buid a sealed box using either a 15" or 18" woofer. I've already purchased a 1000W plate amplifier for the project. I'd like to limit the driver price to <$300. Ideally the -3dB point would be 25Hz or lower. The current listening room is abot 15'x20'.
With the large plate amplifier and active equalization, is there any reason to build a larger box. With the power ratings of the woofers I'm finding in this price range, it appears that I won't be able to fully utilize the amp unless I build a higher Q box.
Initially I was planning to use an AV15 for the design, but I've had trouble getting in touch with the supplier.

Anyways, any suggestions on box designs or driver selection would be greatly appreciated.
 
Since you're in US, try http://www.ascendantaudio.com

They have many drivers in your price range. Call them, they don't answer much to emails afaik.

If you use active equalization, you need a huge amplifier like you have. In a situation where your driver is using 100W for a 40 Hz sinewave, it might require 1000W with active EQ at 20 Hz to achieve the same loudness.

The size of the box with active EQ is less important, but a larger box will be more efficient so you'll have more headroom with your amplifier.
 
Hi Jussi, I have mailed a request asking for price - I will inform when I get an answer

They claim that it will be -3db down at 30hz in a 150Liter closed box, and think of it at 96db
Also I like that its a single voicecoil 8 or 4 ohm
 
badman said:
96dB with an f3 of 30Hz in a 150 litre box? Methinks not. If it were that easy..... life would be good 🙂 Maybe with optimal room interaction.

What's wrong with the numbers? That's for instance the standard numbers for the NHT1259 in a 117 l box. F3 below 30 Hz. With higher SPL...
 
UrSv said:


What's wrong with the numbers? That's for instance the standard numbers for the NHT1259 in a 117 l box. F3 below 30 Hz. With higher SPL...

You seem to be confusing max SPL with efficiency. Max SPL takes excursion and power handling. Efficiency is different, typically requiring lighter diaphragms, stronger magnets, larger surface areas, and bigger boxes. The NHT is more like 88dB range, vs. 96, in terms of efficiency.
 
Not at all. I simply misunderstood due to reading to hastely. I thought you were discussing SPL and not sensitivity. My bad and I should've understood that since 96 dB is not a lot, unless it's sensitivity that is.
 
Frequency response BMS 18" - well I may not have been totally wrong about that - it says about the 18" "neo" driver with +/-13mm linear stroke that its measurements are specified in 150liter closed box - Vb/Fb 150 L/ 28hz - seems to me it is almost straight down to 30hz
 
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