Sound system build progress thread (warning: will be slooooow)

[ashmostro]

While movement in a driver doesn't have much friction, it still has suspension to fight through. Bigger woofer, more weight, more coils all need more suspension which means more resistance and ultimately more power to drive. Look up the part 1 and part 2 research papers titled "Loudspeakers in Vented Boxes" and they go over exactly this.

I am very familiar with Thiele's work, as one of the godfathers of loudspeaker engineering and the first half of the 'T-S' parameters.

This work details how a speaker *system* behaves in various enclosures and how its electrical and mechanical attributes interact with that enclosure. It's all foundational and excellent work and I take no issue with it at all.

I think what's being misunderstood here is that sensitivity is a measured outcome of all of the above. Once you have two 8" subwoofers in ideal enclosures and measure their sensitivity, whichever one is more sensitive is louder and less "resistant to motion". Bringing it back to the original point, the Audiofrog will always be louder than the Rockford in identical sealed boxes, at any power level. And its frequency response will also be optimal at any power level, until you hit the mechanical limits of the suspension.... and that's why the AF is still better. It has more linear Xmax so it's both more efficient and has more high-power potential. It's just a better sub for this application.

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[UWU-mancer]

These mf’s are fighting over magnets and watts….

 

[ashmostro]

These mf’s are fighting over magnets and watts….

Smacks your arm....

 

[UWU-mancer]

Smacks your arm....

Bro hits women!!!!!

 

[ashmostro]

caresses your arm...

 

[UWU-mancer]

caresses your arm...

Thank you

Saint Oya feels better

 

[ashmostro]

Thank you

Saint Oya feels better

In reality, Saint Oya would NGAF

 

[ashmostro]

Thanks to Raw-Cat on youtube, I was able to download calibrated MDAT files for all of my finalist tweeters: The Scan-Speak D3004/602006, Seas 27TFFNC/G, Musway MG6.2T, and Helix Ci5.

This data helped me eliminate the Seas and Musway for distortion and dispersion issues, and reconsider the Helix Ci5 which is a remarkable performer. To top it off, it's tiny and comes with various custom mounts in the box. It's likely my final choice but I'm still debating the Scan-Speak a little because of my love for the brand.

That said, the Helix has better off axis response and surprisingly better distortion than the much more expensive Scan-Speak. And it's WAY smaller. So it will be hard to beat.

Here are some screenshots from REW showing the 0, 30 and 60 degree farfield responses:

Scan-Speak:

Helix:

Musway:

Seas:

As you can see, the Musway has a rapid fall off on the extreme off axis response in the highest registers, and the Seas has a weird diffraction effect of some sort. Those aren't that important because it's at the limit of human hearing. I'm more interested in how consistent the 0, 30 and 60 degree curves are from about 5 to 10kHz. Keeping this spread as tight and "similarly shaped" as possible leads to a much more stable soundstage with varying head position. The Helix does need a little EQ up top to tame some brightness, but that's absolutely not an issue and it's always better to have to take some signal out than put some in.

Some might warn that you should not use a metal dome if you don't like harshness, but it's critical to distinguish between brightness and harshness as they are not the same thing. Brightness is caused by extra sound energy, which can be tamed, while harshness is caused by distortion which cannot be EQ'ed out. That's why you need to look at response (SPL) and distortion to know whether a speaker is a good choice. As you'll see in the next post, the Helix has the lowest distortion between the measured speakers. it won't sound harsh at all in fact it will sound the cleanest.

What the Scan-Speak has going for it is authoritative lower-frequency extension. It's just a beast, and can play loud and low all day. It's the reason I'm considering it, but I think it's probably not worth the trade-offs (worse dispersion, top end response, and distortion).

 

[ashmostro]

Nearfield THD for the Helix:

And the Scan-Speak:

The Seas is bad:

And finally the Musway is quite good:

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