Question

I need help makeing a box for a audiopipe TXX-BDC4-6 6.5 subwoofer what should I do.

How big should I make the box and I wannted to make it vented and to go as low as 35 or 40 hz

Audiopipe TXX-BDC4-6

Audiopipe TXX-BDC4-6

Fs: 60 Hz, Vas: 3l, Qts: 0.48

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+63 vpeti89

10 Aug 2019, 18:40

Hi. That will be a quiet big box on that speaker: Bass alignment +3db @ 40Hz: Vb = 29.4 lts, Fb = 39.5 Hz, F3 = 34.7 Hz.

Box dimensions: WxHxL = 478x400x400 mm, material thickness = 20mm, port -type: L-port, -dimensions: WxHxL = 45x380x1028 mm.

I recomend to use the Quasi-Third Butterworth, or the Max flat amplitude alignment if you wanna be low and space friendly too. These are aligned close to Fb = 50 Hz and F3 = 45 Hz. The max Flat box Vb = 5.3 lts and the quasi box Vb = 7 lts. These are more musical boxes + several times smaller, just the fb and the F3 are a bit higher.

But it is on you, the big box will work well too, just it is very-very big for this speaker. It is on picture.

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Thank you for your help I haven’t looked at my account for a while so that’s why I haven’t seen your post. Thank you for your time and for helping me. I will remember to tell you how the box is when I make it.

Do you have any other box ideas for this driver?

+63 vpeti89

14 Sep 2019, 16:58

Its OK... Just advice what I've learned a few days ago from DD audio: try to find one-way Xmech, because in a car-like listening enviroment is allowed to overpass the Xmax to maximize the speaker's output potential when you push into it 250 Watts RMS in this case, and try to optimize your enclosure for the 85 or 90% of that 1-way Xmech @ 20 Hz to prevent the speaker from damaging itself at low frequencies. There will be some distortion / unlinearity, but it will sound as deep as it can without damaging itself @ 250 Watts RMS. So, try out lower or higher enclosure volume and watch the Cone displacement graph where goes, then adjust the port tuning to reach that value of Xmech - why @ 20 Hz?: simply just on normal music there is no lower bass than 20 Hz. This method works better on an 6th order bandpass, moreover if you will design a 6th order, you can optimize the Xmax and/or the Xmech at any frequency.

For example this is a 6th order bandpass box for this speaker optimised for the speaker's Xmax @ 20 Hz: https://speakerboxlite.com/project-info/18429dfef508a3803f6315196af2cc9173b6ae3c0b1cb305d441aee56b90917e- it will sound not so deep (Fbfront = 66 Hz), but if you know the Xmech, you can optimize it for that 85-90% of Xmech with the Fbfront / Fbrear - you can add lower port tunings - I prefer the low-tuned chambers port. So, I dont know what is the 1-way Xmech for this speaker, but let's say that is 10 mm, so it can be optimized to 9 mm @ 20 Hz, the Fbfront = 46 Hz, and finally the excursion of the speaker @ 10 Hz is less than 10 mm: https://speakerboxlite.com/project-info/8027f26f75fd879d4fff0ceb1119b1f8ffcda2e971202c772631944e1d50e385. Anyways, the speaker's FS = 60 Hz, and in my opinion it is better to tune the port to higher frequency than FS.

And other thing is the cabin gain and car's resonant frequency, I found this video where are well explained @ 12:57: https://www.youtube.com/watch?v=HISsqb3Wh2o.

Or if you will design a ported box, and the Xmax / Xmech you cannot optimize, you will have to reduce the power to prevent the speaker from damaging itself...

What about a box that is around 40 or 50 hz

I see you make a lot of stuff for the service. How I can write to you? Maybe Facebook or do your account email valid? :) I have an offer for you.

+63 vpeti89

15 Sep 2019, 19:47

First I find out that, there is no way to optimise this speaker's Xmax and Xmech to not overpass them with a ported box (like with a bandpass), so be careful with the power.

It seems to be a very good speaker, so I decided to experiment with ported enclosures and I made first a comparison-like project. The Max flat amplitude and the Optimum volume (recomended) boxes will sound the most deep of the "50ish" boxes - see the graphs:

On the other hand, I desined unique enclosures what are tuned to 37.5 Hz (what is perfectly between 35 and 40 Hz - your personal need) and 46 Hz. Outer dimensions are acceptable on both, there is a loss in db at higher frequencies like the Fb (see Amplitude response graph), but in my opinion seems to be they will work well.

At the 46 Hz box the loss is less than 1 db and the speaker's excursion is still a little bit less than the Xmax @ port's Fb = 46 Hz - these 2 things are the reason why I am thinking, that the 46 Hz tuned box is the "limit" box what is still safe for this speaker with still compact outer dimensions. The 37.5 Hz box in my opinion is still compact, but there is a bigger loss in db and the speaker's excursion is higher @ Fb.

I used labyrinth ports, because L-port or round port probably will not fit in the boxes because of the length. They will fit in if the port area is less than minimum recomended, moreover the labyrinth port is possible to make with bigger port area like the minimum and still fits in the box - if my knowledge is right, this gives an extra "boom" and reduces the port wind. So that is the reason why I designed the port with a much bigger area than minimum recomended and choosing the labyrint port.

It depends on you how big box you want to build (how much space do you have for the box), and for what will you use it, so if you want to design a different ported box, this method probably will work well for you like for me:

  • Type the Fb what you want to tune the port
  • Type a very small Vb
  • Increase the Vb
  • Watch Amplitude response graph: if the line reaches or overpass a little bit the 0db line @ Fb, that is the correct Vb for that port tuning with a still compact and / or acceptable outer dimensions of the box (but there will be some losses at higher frequencies like the Fb).
  • If you want to remove the losses, increase the Vb further, but the speaker's excursion will overpass the Xmax @ Fb, and the outer dimensions will not be so compact.

So, in my opinion that 46 Hz box will be OK, but the Max flat amplitude box is the most compact of these 4 boxes. But it is on you, you can design a box with lower Fb, just it will not be so compact, and be careful a bit more with the power.

And other thing, I just can not find nowhere the Xmech parameter for this speaker, so I dont know what are the final limits of this speaker...

Yup, i got basicly the same Driver ESX QE622. it is the same as the Redline 506d from DD and yours.

I made a 22 Liter Tube. But you can also make a box with 22 liters and put a 75mm round Port on it with a length of 35cm and you're good to go.

Frequency range is very nice and it has its loudest peak from 39 to 50 hz.

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