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-   -   Keystone Sub Using 18, 15, & 12 Inch Speakers (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers.html)

weltersys 5th October 2019 02:47 PM

Quote:

Originally Posted by wreckingball (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post5934664.html#post5934664)
1) Reducing cabinet width may actually be an improvement for a 15", but you will need to experiment with the exit size. As a starting guess, I'd reduce the exit dimensions by the same % as the cabinet width and height are reduced.
And bolded ..is this still your starting guess? I'm still considering experimenting, so clarification would be great.
2) Speaking of which, can someone point me to a thread or link that spells out what I need to determine how much voltage/wattage I'm feeding to a driver in a high-power/PA type scenario, and for testing them in general for that matter.. (?)

1) Reducing the width should not have much effect on Fb, but reducing height would shorten the path length, which would. The Eminence 15" I used when originally making the comment did not work well with the stock Keystone, while the Dayton 15 later used in the taller version had quite similar frequency response to the BC18TBW100.
2) You can get a good idea of the peak watt output simply using the meters on your amplifier, the NU6000 hits 3000 watts into 4 ohms when the "0/limit" lights, the -6 dB light would be around 750 watts, -12dB 187 watts, -24 12 watts.
Depending on the crest factor of the material being played, the average power could be equal for a sine wave type signal (3 dB crest factor) or as little as 5% for music with a wide dynamic range.

Art

mwmkravchenko 5th October 2019 03:01 PM

Quote:

Originally Posted by weltersys (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post5934226.html#post5934226)

Seems most of the people building the Keystone run them at levels that would "break in" the driver in a few hours, but glad to hear yours are housebroken!

Cheers,
Art


Probably the reason why they are called woofers in the first place :D

Aardvark87 6th January 2020 10:37 PM

Single Amp possible?
 
I'm looking into driving 4 Keystone subs - two in parallel on each channel - with a single Powersoft K20 (or even a K10). I have 18SW115-4s in the subs. I was wondering if I could run into potential problems then doing that, since it's a lot of power running into 2Ohms. Because if one driver fails...the other one on the same Channel is not going to like it. The idea is to reduce the rack size and weight to a minimum.

weltersys 7th January 2020 03:27 PM

Quote:

Originally Posted by Aardvark87 (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post6034884.html#post6034884)
I'm looking into driving 4 Keystone subs - two in parallel on each channel - with a single Powersoft K20 (or even a K10). I have 18SW115-4s in the subs. I was wondering if I could run into potential problems then doing that, since it's a lot of power running into 2Ohms.

Aardvark87,
The K10 does 6000 (peak) into 2 ohms, 3000 per driver compared to 4000 at 4 ohms, less than 1 dB difference.
The K20 does 9000 into 2 ohms, 4500 per driver compared to 5200 at 4 ohms, again less than 1 dB difference.

If you are worried about blowing a second speaker because of a one dB difference in level to it, set the limiters so you don't blow the first speaker ;)

Cheers,
Art

Abielpanggabean 10th January 2020 02:49 AM

Hey art,
 
Quote:

Originally Posted by weltersys (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post6035546.html#post6035546)
Aardvark87,
The K10 does 6000 (peak) into 2 ohms, 3000 per driver compared to 4000 at 4 ohms, less than 1 dB difference.
The K20 does 9000 into 2 ohms, 4500 per driver compared to 5200 at 4 ohms, again less than 1 dB difference.

If you are worried about blowing a second speaker because of a one dB difference in level to it, set the limiters so you don't blow the first speaker ;)

Cheers,
Art


Abielpanggabean 10th January 2020 02:52 AM

Guys i wonder, what happens if we don't bend the horn path inside the box?

weltersys 10th January 2020 04:10 PM

Quote:

Originally Posted by Abielpanggabean (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post6038883.html#post6038883)
what happens if we don't bend the horn path inside the box?

We don't have a "tapped horn" anything like what we designed.

Abielpanggabean 11th January 2020 04:08 AM

What i mean is, part g and h in the plan is not straight and has a certain angle to it. What happens if i don't follow that and make it straight?

weltersys 11th January 2020 06:32 PM

Quote:

Originally Posted by Abielpanggabean (https://www.diyaudio.com/forums/subwoofers/185588-keystone-sub-using-18-15-12-inch-speakers-post6040164.html#post6040164)
What happens if i don't follow that and make it straight?

If you change all the parts to have 90 degree angles rather then the angles as designed, the cabinet frequency response will change.
The change probably won't be for the better ;)

Abielpanggabean 12th January 2020 12:39 PM

Do you have any measurements?


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