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The quest for more bass...........

5K views 40 replies 9 participants last post by  Ryan Anderson 
#1 ·
So after building my 18" with dual 18 pr's I find myself still not satisified with the low end output. There's nothing wrong with it, I'm just still thirsty for more low end.

That being said I'm looking for ideas on a new build. I have a spot allotted below my screen for a stereo cabinet, but I do have an equipment rack in another location I can store the gear in. The space is 63"w x 23.5 high. I can do something about 20" deep if I had to.

I'm looking for lots of low end and maybe some mid punch as this will be strictly used for movies. I'd like to do an efficient design that's not difficult to build as I'm limited by tools.

My amp is a Yamaha P2500S rated at 1300 4 ohm bridged.

I'd ideally like to use the woofers and amp I already have. If anything has to change I can look at a more powerful amp, but that's a last resort.

Here's a pic of the screen wall to be..


Thoughts? Thx
 
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#9 · (Edited)
Here's a quick winisd model showing closed, vented and passive.
Passive in pink, vented is grey, and closed is yellow.


Here's the cone excursion - the PR, and vented need an HPF, but the cone excursion on the sealed is wicked at 1300 watts. at 800 watts it looks much better (not shown).

the PR has 1600g mass on it.
the vent is 4" wide x 6" long




and the SPL


For H/T which one looks best?
 
#16 ·
uh huh

Ported Ported Ported..... Sealed looks weezy compared to the ported. The sealed looks like its almost 8db down at 20hz. Ouch!

cheers
graham
no what im sayin?

I'm still learning as I go, but I'm starting to grasp all this modelling stuff. I tinkered with this stuff about 20 years ago so it's all starting to come back to me At least I can grasp what's going on. With regards to the PR's I tinkered with WinISD and was able to get within a db or so of the ported design with the PR's.

I bought a cheap furniture mover at costco, and moved my box around my room to find the best spot. Turns out the best spot is in the back corner behind the sofa. Wierd, but it sounds the best there. I have a crazy idea to build a tall, narrow corner box with the active woofer down low and the PR's closer to the top. It could possibly almost look like a corner bass trap :). Maybe a big sonotube would end up there.

I should never come on here before bed as now I'll never fall asleep as I have bass flowing in my veins LOL.:cunning:

they had WinISD for the Commodor 64?


hehehehehe... I ate up the PRs with Pac Man
 
#13 ·
When I've modeled passive radiators compared to vented and get what you are showing in your graphs, it usually means that you either have too much weight or too large of a volume on the passive model. You get that large choppy slope like that if it is off. You should be able to get the passive setup to stay near the output of the vented, it will just start rolling off like the vented is doing a little earlier.
 
#15 ·
I'm still learning as I go, but I'm starting to grasp all this modelling stuff. I tinkered with this stuff about 20 years ago so it's all starting to come back to me At least I can grasp what's going on. With regards to the PR's I tinkered with WinISD and was able to get within a db or so of the ported design with the PR's.

I bought a cheap furniture mover at costco, and moved my box around my room to find the best spot. Turns out the best spot is in the back corner behind the sofa. Wierd, but it sounds the best there. I have a crazy idea to build a tall, narrow corner box with the active woofer down low and the PR's closer to the top. It could possibly almost look like a corner bass trap :). Maybe a big sonotube would end up there.

I should never come on here before bed as now I'll never fall asleep as I have bass flowing in my veins LOL.:cunning:
 
#22 ·
I would say that it might be too close to the ceiling...

One thing to think about, is the fact that you might need to have a baseplate. Or, you could leave it with no baseplate, but the bottom of the box will still have to be ~5 inches away from the floor, so your useable distance from the top of the box to your ceiling will be down to ~2 inches.

It says in the Sonotue program that the total box height will be 95.48 inches, so it would be REALLY close to the ceiling. Can you experiment with different widths of the Sonotube? That would be your best option, because I would say that it will be too close to the ceiling as it is.
 
#26 ·
I like the gray plot. Smooth and rolls off cleanly.

What are you listening to at 15 Hz?... Probably nothing.

Ported properly is hard to beat! I like long 6" PVC ports for HT use. No chuff.

Any way you cut it a big box is needed to get low and flat.

On a side note: Why so much gap in your drywall top and bottom? And if the framing on the speaker wall is sitting on concrete it needs to be PT. I cannot tell from the picture.
 
#27 ·
I'm not listening to much at 15 HZ really. The sub is strictly for H/T use so if the content is there I want it to really get the most out of it. I may as well tune it low and I have the space to do it.

The gaps top and bottom on the screen wall or on the other wall? I think you're referring to the other wall. My ceiling height now is about 8'6. I'm doing a drop so you won't see the gap at the top anyways. The bottom gap will covered by trim anyways, and if the basement ever leaks the drywall shouldn't get wet.

I built my house last year and I live in cold winter climate. The outisde walls are 2x8 and are fully lined with sprayfoam. I can crank up my system and not hear a peep outside. I have an R value of 35 for warmth, and the side benefit is great soundproofing :)
 
#28 ·
Nice R value! Exactly what I would do for a personal home with new construction. Just don't open the front door ;) Actually windows are the achilies heal on thermal efficiency.

I ask about the frequency because the lowest natural musical noise will come from pipe organ music... And who listens to that!? For HT use who knows what is blended in, but I doubt you need to go that low.

On mine I tuned for 19 Hz and have been very pleased with a 15" Adire Brahma MK1 in a 8ft vented box. Very flat curve and then drops smoothly and quickly.

... Before I had been playing around with 10s and dual 12s and none of them can match the low end of the larger diameter subs with xbl2 technology. The 30 Hz area is much stronger!

Everyone thinks it is nuts, but you have to go ported for a truly flat curve. IMO sealed is the worst for SQ as you loose all the bottom end in an effort to prevent peaks in the top of the low end.
 
#29 ·
Everyone thinks it is nuts, but you have to go ported for a truly flat curve. IMO sealed is the worst for SQ as you loose all the bottom end in an effort to prevent peaks in the top of the low end.
Well, there's this thing called EQ.....

With EQ, some room gain and signals with a decent peak to average ratio, sealed is fine and goes deeper w/o needing a subsonic filter to prevent over excursion.
 
#31 ·
Thanks for the input - I'll keep tinkering with the model.

The only reason I tuned it a bit higher is because my basement area is quite large and open. The theatre area is 13x27 with an l shaped corner at the back that leads to another area, and the front is open with the staircase on the left in the picture.
 
#32 ·
Well, there's this thing called EQ.....
Then you start to work your amplifier to hard. Most people do not tune the EQ down, only up which loads up the amp. Especially in a sealed box you would have to EQ the bottom end up to match the upper low end. With a ported flat curve you can EQ down in the middle (40-50HZ) to compensate for room gain, if any.

Depending on the Sub design unloading it a bit may or may not hurt it. Also depends on the power being sent to the Sub and of course the size of the enclosure. WinISD should be of help here... I think a lot of people overpower subs in large enclosures which can lead to over-extension.
 
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