its the horn that makes it sound the way it does. honestly, my first drivers were cheap china crap. and they sounded great. then the second set were even weaker, and still sounded good!!! they now have good drivers, it does make a difference, but seriously. build just one. $100. you will have a better sub than anything youve ever heard. and it will outdo 3 of the same speaker in reflex cabs.
i promise.
i promise.
here are my first reactions when i built mine
my build>
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-23.html#post2751133
and my first impression after taking them out to a local golf club for a friends engagement.
my build>
http://www.diyaudio.com/forums/subwoofers/170771-single-sheet-th-challenge-23.html#post2751133
and my first impression after taking them out to a local golf club for a friends engagement.
No way would I contemplate buying ANY new drivers.
More than my marriage and my manhood is worth at the moment.
Nope; if I do build one it would have to be with one of the subs on the shelf and the MTX 15s are sacrificial and are the only drivers I would be willing to experiment with.
Fs is actually lower than the factory spec. First resonance is at 18Hz with a secondary ( and annoying ) at 21.
More than my marriage and my manhood is worth at the moment.
Nope; if I do build one it would have to be with one of the subs on the shelf and the MTX 15s are sacrificial and are the only drivers I would be willing to experiment with.
Fs is actually lower than the factory spec. First resonance is at 18Hz with a secondary ( and annoying ) at 21.
OK
last pictures
Hi,
I don't know how accurate the specs you posted are, but assuming those specs, the driver does fairly well in the SS15 design.
Here's a comparison of the SS15 (black trace, about 260 liters total internal) to a 30Hz vented box (grey trace, about 130 liters total internal)
As you can see, the horn gets about 5dB more output above 40Hz, (subjectively half-again as loud), however it won't go as low. you could lengthen the top part of the horn by about 25cm (increasing the total path length by about 1m, and about 100l bigger box). If you do this, you are about the same loudness as the vented box, but going deeper, pretty flat down to 30Hz and solid into the 20s.
Hi Y'all,
I'll attach Hornresp Input and SPL screens for jbell's SS15 w/ the Avico 12". There is not much going on in the initially desired frequency low end. On the contrary, for this driver and this box a good low cut filter would be at around 35-40Hz to prevent excessive excursion at high input power. Yes, it would work, but it would not come close to 25-30Hz.
Regards,
I'll attach Hornresp Input and SPL screens for jbell's SS15 w/ the Avico 12". There is not much going on in the initially desired frequency low end. On the contrary, for this driver and this box a good low cut filter would be at around 35-40Hz to prevent excessive excursion at high input power. Yes, it would work, but it would not come close to 25-30Hz.
Regards,
Attachments
To add a bit more, at 20 Hz, a 5 dB difference sounds twice (or half) as loud to our ears.
The SS15 w/ the Avico 12" is about 30 dB down at 20 Hz, it simply is not a bottom octave contender whatsoever.
Art
?
I wonder where the end of that sentence went to??
It should have read like this]-
The pair I would consider using in a tapped horn are the 15inch MTX subwoofers I already own.
Having such a relatively low Fs I thought they would need a tapped horn with a really long length for an 18 Hz resonance to work in below the cut-off for the 12 inch in a sealed box.
I am having a little trouble learning how to "Drive" the Horn Response program.
Fs (Factory 22.7 Actual 18Hz )
Sd 856cm>2
DCR 3.29
Le 2.6mH
Qes.56
Qms11.96
Vas 315
As measured on WT at the local shop a year or so ago very close to the factory spec except for the lowered resonance
It should have read like this]-
The pair I would consider using in a tapped horn are the 15inch MTX subwoofers I already own.
Having such a relatively low Fs I thought they would need a tapped horn with a really long length for an 18 Hz resonance to work in below the cut-off for the 12 inch in a sealed box.
I am having a little trouble learning how to "Drive" the Horn Response program.
Fs (Factory 22.7 Actual 18Hz )
Sd 856cm>2
DCR 3.29
Le 2.6mH
Qes.56
Qms11.96
Vas 315
As measured on WT at the local shop a year or so ago very close to the factory spec except for the lowered resonance
Hi moondog55,
I entered your MTX 15" data into Hornresp for you. Here are three simulations, BR, TH, T-TQWT. For sealed just zero out Ap and Lpt. That ought to get you started.
For the simplicity of the build and the size I'd go w/ the BR, just double the volume, etc. for a dual (V_int~254 L_net for the single).
Regards,
I entered your MTX 15" data into Hornresp for you. Here are three simulations, BR, TH, T-TQWT. For sealed just zero out Ap and Lpt. That ought to get you started.
For the simplicity of the build and the size I'd go w/ the BR, just double the volume, etc. for a dual (V_int~254 L_net for the single).
Regards,
Attachments
That's interesting as when I enter the data into JBagbys program I get a reflex size of 2455 litres optimum. Sealed I get a reasonable response in 300/400 litres, the alternative which I used and did not like was a small box( 155 litres ) with a first order pass at 18Hz.
BTW that box was very suitable for a 15inch Kicker I got cheap and is now part of my HT and stereo system, very poor WAF
BTW that box was very suitable for a 15inch Kicker I got cheap and is now part of my HT and stereo system, very poor WAF
As Art said, the news is better than expected. 5db equates to about twice as loud. 10 db is twice as loud in the midrange, but if you look at the equal loudness contours, you realise that bass is different. Typically 6db equates to twice as loud, but as the level goes up higher, the db increase required for percieved doubling of output goes down. I wrote about it here:
Red Spade Audio: Loudness perception and bass
Take a close look at the equal loudness contours and you might notice a few things easily missed.
Thanx Paul
I was aware of it but it puts things in a clearer perspective.
I still see no clear advantage over the closed box for those cheap woofers given the ease of building the sealed box. it is more a matter of my funds than perfection at this stage
I am however interested in the possibilities of a tapped horn when I can fund the plywood and I would have thought the MTX subwoofers were actually better for this.
I was planning an wide OB with a 12inch mid-woofer using these drivers
I was aware of it but it puts things in a clearer perspective.
I still see no clear advantage over the closed box for those cheap woofers given the ease of building the sealed box. it is more a matter of my funds than perfection at this stage
I am however interested in the possibilities of a tapped horn when I can fund the plywood and I would have thought the MTX subwoofers were actually better for this.
I was planning an wide OB with a 12inch mid-woofer using these drivers
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