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Best 15 Inch Sub for ~82L Sealed Box

jhaider

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Yeah I was thinking about this but I got the impression that I should just go for the one with higher xmax and power handling, which in this case is the MX15.

I wouldn’t.

I would counter that shorting rings are not very important for sub bass frequencies as they can't be made thick enough to have effect. Stamped frames also they are associated with cheaper drivers but do they have issues in the sub bass range?

You clearly did not suffer through the era of super long throw overhung-motor drivers with no inductance control. Yes, one can equalize out the nauseating upper-bass hump inherent in these crude air pumps, but even after doing so they are audibly different from modern drivers. Try to pick up one of the ****** bass pumps of that era - Ascendant Audio Avalanche, Elemental Designs, some Stryke/Acoustic Elegance (TC Sounds made) HE15 or similar TC-made Eclipse drivers, etc. - and compare to a driver with some attention paid to inductance control. A comparison that vividly hammered it home to me was a TC Sounds TC2+ (Oaudio brand) 15" driver and a TC Sounds 3HP (I think - Stryke/AE HE15 brand ) driver. TC2+ was their base model, but newer in design and had shorting rings in the motor. HE15 was longer throw but and more expensive but a lesser design. I did the comparison back in the day, equalized for the same nearfield response using a Velodyne SMS-1. It was not close - TC2+ 15 added musical foundation, HE15 added a loud dull thud.
 
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Felix2

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Hmm, could the UM15 be considered a middle ground between the RSS390HF and the MX15? It seems like a way higher quality driver than the MX while also having a bit more power handling and xmax compared to the RSS. I think it has shorting rings too?
 

ppataki

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Hmm, could the UM15 be considered a middle ground between the RSS390HF and the MX15? It seems like a way higher quality driver than the MX while also having a bit more power handling and xmax compared to the RSS. I think it has shorting rings too?

I have made some simulations for you for all three subs in a 82 liter sealed box
MX15: red
RSS390HF: orange
UM15: yellow

You can see the cone displacement at 800 watts:

1675684691156.png


The MX15 and the UM15 will be just fine, they could handle even more power; the RSS390HF will be limited to around 430 watts:
The MX15 seems to have the lowest displacement down to 10Hz - probably lower distortion as well but this is just a speculation

1675684793068.png


At 430 watts here is your SPL at 20Hz at 1 meter for one speaker:

1675684864311.png


They are pretty much aligned, 101.7dB MX15 - 103dB UM15 -103.8dB RSS390HF

In terms of impedance the MX15 is worse vs the others:

1675685002149.png


Group delay, which I believe is the most 'qualitative' curve here looks like this:

1675685057391.png


Between 20 and 40Hz the MX15 is the best but then between 50 and 100Hz the others are better

To be honest, I would struggle to say which is the best just based on these simulations.......
 

fpitas

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You know your actual needs best. But unless you're a super-duper basshead, and/or you have a giant room, any of those will probably work fine. The RSS390HF will shine above maybe 60Hz, if you care.
 
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Felix2

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I have made some simulations for you for all three subs in a 82 liter sealed box
MX15: red
RSS390HF: orange
UM15: yellow

You can see the cone displacement at 800 watts:

View attachment 262796

The MX15 and the UM15 will be just fine, they could handle even more power; the RSS390HF will be limited to around 430 watts:
The MX15 seems to have the lowest displacement down to 10Hz - probably lower distortion as well but this is just a speculation

View attachment 262797

At 430 watts here is your SPL at 20Hz at 1 meter for one speaker:

View attachment 262798

They are pretty much aligned, 101.7dB MX15 - 103dB UM15 -103.8dB RSS390HF

In terms of impedance the MX15 is worse vs the others:

View attachment 262799

Group delay, which I believe is the most 'qualitative' curve here looks like this:

View attachment 262800

Between 20 and 40Hz the MX15 is the best but then between 50 and 100Hz the others are better

To be honest, I would struggle to say which is the best just based on these simulations.......
Thanks for taking the time to do this! Indeed they all look very similar... Maybe I'll just get the UM15 as it seems like a higher quality driver than the MX15 and it also allows me to upgrade to a larger vented box in the future if I want even more output.
 

voodooless

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To be honest, I would struggle to say which is the best just based on these simulations.......
In MaxSPL, they are all within about 1 or 2dB, so no need to worry about that. The HF and UM are the more efficient drivers, so will need less power. The MX has a massive inductance of more than 5 mH! I don't know if I would be happy with that. Given the small price differences, I would probably go for the UM15 or RSS. The RSS has a cleaner response even past 1 kHz. If that is important then take note. I think there are some measurements of these somewhere to be found in the wild. If I recall, they are both quite good.

Also, consider making the box larger. A double-sized box will give you about 3dB more output at 20 Hz.
 
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Felix2

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In MaxSPL, they are all within about 1 or 2dB, so no need to worry about that. The HF and UM are the more efficient drivers, so will need less power. The MX has a massive inductance of more than 5 mH! I don't know if I would be happy with that. Given the small price differences, I would probably go for the UM15 or RSS. The RSS has a cleaner response even past 1 kHz. If that is important then take note. I think there are some measurements of these somewhere to be found in the wild. If I recall, they are both quite good.

Also, consider making the box larger. A double-sized box will give you about 3dB more output at 20 Hz.
I'll try the UM with the enclosures I have. If I'm not satisfied I can always build something larger :D
 

fpitas

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I think you'll be happy. The Dayton drivers are nice.
 
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Felix2

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I have one final question as I'm ordering the subs next week.
This time it's about sensitivity. I noticed that the UM15 has a way lower sensitivity than the RSS. However, when I model them both with 300w of power in 83L boxes the UM15 ends up with slightly higher output according to winISD. How is this possible? Shouldn't the RSS be playing louder?

UM15 sensitivity: 86.5 dB @ 2.83V/1m
RSS390HF sensitivity: 91.2 dB @ 2.83V/1m

Here's what it looks like in winISD with the aforementioned inputs (300w, 1m, 83L). Yellow is UM15, blue is RSS390HF

1676223178510.png
 
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