I determine the vent size by getting at my sim computer, plugging the numbers i have (the PE alignment, the vent length, height, and then i use the simulators vent calculator to spit out the appropriate width which determines how big the vent spacer needs to be.
dave
dave
Changing 5.75x5x6 to 5.75x5x6.5 = 3.06 litres.
This is what i’d do — note that the vent spacer width is unknown, i had a power failure last nite and haven’t gone down to turn my modeling computer so can’t figure it yet. If it turns out to be too wide, i’ll shrink the vent height.
Uses 12mm ply, and all dimensions used, except the starting internal dimensions, are metric.
dave
Note: drawing updated to reflect missing information
Awesome thank you! I noticed it says I need to cover the walls with felt or cotton. Is that 100% necessary? Also the vent divider goes all the way to the back of the box correct? Thanks
Some damping material is needed to kill some of the internal reflections. Yes, vent spacer goes all the way to the back of the box.
dave
dave
67 Hz is the box tuning. The model suggests anechoic response of F10 ~ 50 Hz, F6 ~ 53 Hz. When talking speakers F3 is only menaingful in terms of defining the filter the roll-off emulates.
dave
dave
Dave, I got the speaker in the mail today and hooked it up to my amp. When I use the Bluetooth feature on the amp board a sort of intermittent static plays. Do you know of anyway to fix this? I bought it cheap off amazon so that could have some effect in it... Amazon.com: UCTRONICS TDA7492P Stereo Amplifier Board, 25W+25W Dual Output, Wireless Bluetooth Receiver 4.0 or 3.5 AUX Audio Input Digital Amplifier Module, DC 8-25V Input Voltage: Home Audio & Theater
Ask the question in Class D forum. This looks a lot like the Sanwu board with TPA3116 amp. It had noise problems and that was fixed by bypassing a buffer amp between the BT module and the amp inputs and utilizing the balanced line drive feature. It's not an easy fix. If you don't like BT noise, use a non BT amp.
SANWU TPA3116 + CSR8635 Bluetooth 4.0 - Noise Fix
SANWU TPA3116 + CSR8635 Bluetooth 4.0 - Noise Fix
Get this instead and take its output to your amp. It works very well no noise and lets you play mixroSD or USB drives too. Output goes to your power amp. Any stereo amp will work and I suggest a Class AB to reduce noise pickup.
Bluetooth audio receiver board with USB decoding before the class output SANWU TF card original producer-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
Bluetooth audio receiver board with USB decoding before the class output SANWU TF card original producer-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
Okay thanks. The noise isn't too bad at the moment if it gets worse I will look into that as it is very cheap. I temporarily fixed the problem by clipping a piece of wire to the antenna... seems to work.
Dave do you have any suggestions on cutting the piece that has to be 10mm tall? Sanding would work but would take awhile...
I just draw em, i don’t build them.
You could make it 12mm with a 54mm vent spacer (leave 12mm at the back of the vent shelf)
dave
You could make it 12mm with a 54mm vent spacer (leave 12mm at the back of the vent shelf)
dave
For the noise fix..... try attaching a small piece (6-10") wire to the tip of the BT receiver antenna. It helped to reduce the hiss noise in my TDA7492 based amp.
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Changing 5.75x5x6 to 5.75x5x6.5 = 3.06 litres.
This is what i’d do — note that the vent spacer width is unknown, i had a power failure last nite and haven’t gone down to turn my modeling computer so can’t figure it yet. If it turns out to be too wide, i’ll shrink the vent height.
Uses 12mm ply, and all dimensions used, except the starting internal dimensions, are metric.
dave
Note: drawing updated to reflect missing information
Dave....In the updated file, the slot dimensions shown are 40mm x 10mm (vent opening) by 146.1mm (vent length). Are the other portions, the entrance and exit, not counted in the vent length for calculations.
Can anyone let me know the calculations for the tapered port below. I cannot find answers for tapered port calculations. The Jantzen Audio pdf file (part no. 051-0008) below says that it is 26.3mm inside opening and 35mm outside opening and overall length is 165mm. What should be the diameter to consider for calculations?
The only thing that I could get was that a tapered port with a wider opening towards the outside slows down the airflow and reduces port turbulence at the cost of efficiency.
http://www.jantzen-audio.com/wp-content/uploads/2013/09/Port-Tubes-2017.pdf
Jantzen Audio - 1-1/8" ID x 6-1/2" L ( 35 / 165mm ) - Flared Port Tube
The only thing that I could get was that a tapered port with a wider opening towards the outside slows down the airflow and reduces port turbulence at the cost of efficiency.
http://www.jantzen-audio.com/wp-content/uploads/2013/09/Port-Tubes-2017.pdf
Jantzen Audio - 1-1/8" ID x 6-1/2" L ( 35 / 165mm ) - Flared Port Tube
I should have added a dimension to the vent shelf… 136mm… there is no explicit dimension for the vent length.
dave
Do not try to substitute a tube port in my box, the tuning assumes the high R, high ratio vent.
dave