Box for jl 12W0v3-4

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#25
I tried a ported simulation with hornresp just double check and I noticed acoustic power chart looks the same as Bassbox ... except for when I input Pmax and Xmax, then it all goes to s**t with dips, and clipped peaks. Should I be worried?
 
#26
Well, it's showing you that you're exceeding Xmax at those frequencies/power, so up to a point not a major concern at higher frequencies, but as you go downwards the excursion is increasing by 4x/octave, rapidly reaching a point it's going to damage the driver enough to require re-coning/replacement.

If you want to know approximately where this point is you would need to input the driver's Xmech value and if there's no dips/clips, then you may be OK, though run often at that power for any length of time [such as an organ pipe sustain] will not only cause a distorted performance, but also overheat it enough to probably damage it, so a good plan is to input a slightly higher Xmax and find the power rating where the dips are just starting to show and that's your usable peak [not average] power rating.

GM
 
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#28
OK, 310 W is only good to ~60 Hz, so ideally need to get it down to at least the 24 Hz tuning [preferably to 0.707x it = ~17 Hz] for best protection since this is a 2 pi sim. Unfortunately, HR's 1, 4 pi sims are increasingly optimistic, so at most I personally wouldn't go beyond adding a couple of dB if on the floor against a wall or 4-5 dB if in a corner to whatever power rating yields no red to 24 Hz.

GM
 
#29
GM said:
OK, 310 W is only good to ~60 Hz, so ideally need to get it down to at least the 24 Hz tuning [preferably to 0.707x it = ~17 Hz] for best protection since this is a 2 pi sim. Unfortunately, HR's 1, 4 pi sims are increasingly optimistic, so at most I personally wouldn't go beyond adding a couple of dB if on the floor against a wall or 4-5 dB if in a corner to whatever power rating yields no red to 24 Hz.

GM
Click to expand...

The thing is, the chart shows clipping on anything above 9W, I only entered the 300W value based on the driver's max RMS.
 
#30
Sounds about right down low since [1] tuning is <Fs, [2] super high Qts for vented = large box/very little driver air mass 'spring' restoring force. Put it in an optimum TQWT tuned to Fs though and it will handle 100 W with very little overdrive from ~20-60 Hz where the room/boundary loading will increase SPL and the full 300 W above ~60 Hz same as your sim where most of the 'slam' is in music. Doesn't make anymore deep bass, just is smaller and can 'sink' more power [heat], ergo more driver protection due to a stronger air mass 'spring' with potentially more distortion though.

Personally, I prefer acoustic efficiency, but then I was 'raised' on relatively low power amps where we were always seeking as much acoustic efficiency as practical.

Regardless, HR 'crashed' when I tried to save one of the sims, so need to update, re-do them for you to browse later; got some car repair to deal with first though.

GM
 
#32
Hmm, forgot to do the sims. 🙁

Which peaks? Small HF ripples? Lining the cab walls suffices. Vent peaking or just its harmonic ripple? [Critically] damping the vent to a greater or lesser extent suffices.

Room modes can be EQ'd for a single narrow listening location, but it takes room design and/or damping to do it properly for over a wide listening area.

GM
 
#33
https://www.diyaudio.com/forums/<a href=https://postimg.org/image/4u6uuhkgd/ target=_blank>[IMGDEAD]https://s14.postimg.org/f499tqac1/image.png[/IMGDEAD]Something like this.

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[URL="https://postimage.org/"]][/URL][URL="https://postimg.org/image/4u6uuhkgd/"][IMGDEAD]https://s14.postimg.org/f499tqac1/image.png[/IMGDEAD][/URL][URL="https://postimage.org/"]picture hosting[/URL]
 
#34
Ideally you need a high pass [rumble] filter to protect the driver down low, but you can use EQ to approximate it if it's at least 1/3 octave. I tried doing it with a one octave EQ back when they were the only ones that were reasonably cheap and it didn't work too well. Note that not dealing with the lowest peak may make for some annoying 'boom' if there's any loud signal in this band-width [BW]

GM
 
#38
Don't know, though guessing you'll need to put them in ~form fitting tubes to brace them. When I've used them to tie Sonotube' sub's pedestal, driver, baffle, end wall together I used the largest size that fit the driver mounting holes and sometimes reamed them out a bit along with alum. tubes between the pedestal, baffle to conceal them and just covered them inside with FG insulation.

GM
 
#40
Bad link since it's not an image, just a link to an image. 😉 https://postimg.org/image/6l53hc4i5/

It's a fairly large cab, so need at least [3] sets.

Also need a vertical riser to tie them all together to keep the cab from 'breathing' and ideally should support/mass load the driver; where 'mass loading' means to slightly press against it just enough to clamp it to the baffle [put it in tension].

This of course is usually done by leaving a small gap and shimming it as required: http://www.frugal-phile.com/boxlib/GM-A10-MLTL.pdf

GM
 
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