Street Bass box

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Street box

Hi everyone
I am designing (copy) a dual ported lab12 box that I see flowing around. I did a little adjustment to the box for it to have four triangle port instead of two.

Can someone please let me know if the adjustments I made are ok.

Thanks



Lab12 port.jpg
 
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Would it be better it I design the box a little wider.
Better for what?

The thin box gives increased frontal area, which is a good thing for a single cabinet, but bad for stacking on.
Or if the speakers go on the thin side, decreases frontal area, good if you want to cram lots of speakers in a small frontal area.
Four ports strengthen all the corners, a good thing, but may require bends (if the front is 28 x 28), which will mean experimentation to see if the box Fb remains as designed.

There must be a reason you are planning to change my design, I just don't understand what your reasons are.

At any rate, I have a pair of the originals for sale, unloaded, loaded with a single Lab 12 and a cover plate, or unloaded if anyone is interested, cost is around materials + shipping from 87505.
 
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he means that because you have increased the number of vents, you have likely increased the overal vent area, meaning your vents are now longer to achieve the same tuning (although you do reduce port velocity). now if you change the depth of the design, you may have to "bend" the ports to achieve sufficient vent length, which means you may change the Fb, as the vent volume will be taking up some of the volume from the box.
 
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he means that because you have increased the number of vents, you have likely increased the overal vent area, meaning your vents are now longer to achieve the same tuning (although you do reduce port velocity). now if you change the depth of the design, you may have to "bend" the ports to achieve sufficient vent length, which means you may change the Fb, as the vent volume will be taking up some of the volume from the box.

Sine143
Thanks. I learn something new.
 
Made a pair of 2x6 cabinets with a tweeter, the pair of Alpha 6 are not very flat, but cover from 110 Hz to 2 kHz well. Simple build, though fairing the HF horn entrance takes a good bit of filing.
About 95 dB one watt one meter at the bottom and top.
Cabinet is only 26.5 tall, 15' wide, and 11.25" deep.
Eminence APT on top, crossing at about 3.5 kHz.

Once the 2x6T is EQ'd, it sounds quite good and can do around 125 dB.
I cross it at 100 Hz to the sub.
Details here in posts #14 and #23
http://www.diyaudio.com/forums/multi-way/240429-help-first-pa-system-build-3.html

If you are interested and have questions, reply to that post, as it is a multi-way project.
 
Made a pair of 2x6 cabinets with a tweeter, the pair of Alpha 6 are not very flat, but cover from 110 Hz to 2 kHz well. Simple build, though fairing the HF horn entrance takes a good bit of filing.
About 95 dB one watt one meter at the bottom and top.

Just curious, but how much does the horn design improve over using the Alpha in a simple vented alignment?
 
Just curious, but how much does the horn design improve over using the Alpha in a simple vented alignment?
Around 6 dB increase in SPL from 315 to 1200 Hz, as you can see in the raw response, below and above those frequencies are about what the level would be in a simple vented alignment with the same Fb and volume.

Effectively almost like doubling the speakers and amplification, but requires a lot of EQ to flatten the response. That said, even a 10 band graphic EQ can correct the response. The polar response is good, when EQ'd it sounds very uniform off axis, and the 90 degree pattern allows for more gain before feedback compared to a front loaded design.

As a subjective observation, I had the same speakers in small sealed front loaded dual boxes, a pair were just barely cutting it as floor monitors, in the little conical horn (with subs) they work fine for covering 100-200 people for mains.

Art
 

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Around 6 dB increase in SPL from 315 to 1200 Hz, as you can see in the raw response, below and above those frequencies are about what the level would be in a simple vented alignment with the same Fb and volume.

Thanks.

I'm considering using these in another build (which I'll probably finish by Christmas concerning my workload these days!). I was wondering if they were anywhere near as good as their bigger cousins, the Beta 8As. The on-axis response I got with them paired with a piezo tweeter and a very simple x-over was very, very good.

I might go with a simple vented build. The purpose I'm going to be using this for calls for as little EQ as possible. Do the 6As get nasty at upper frequencies if run without x-over?
 
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