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Triticum Agricolam

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Triticum Agricolam last won the day on October 9

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About Triticum Agricolam

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    Male
  • Location
    Eastern Washington State
  • Interests
    Speaker enclosure design & construction

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  1. Ending up with the net volume you desire isn't too tough, you just have to assume the manufacturer has given you accurate information in regard to the displacement of the sub. The good news is that if your net volume is off a little bit its not going to make much difference. Getting the tuning you want is much more of a crap shoot. Tuning frequency calculations are much more of an approximation. Plus there are outside factors that will affect tuning (temperature, barometric pressure, etc). You can test to see what your tuning frequency ACTUALLY is once you get the box playing by playing sine wave tones at moderate volume while watching/feeling for cone movement. The frequency where cone movement is the least is your tuning frequency.
  2. Alpine's suggestion for port area is SIGNIFICANTLY undersized depending on how much power you are going to be running. The 10 sq in of port area they recommend is fine up to about 300 watts, but if you go much over that you are going to want more port area. The nasty part about an undersized port is you don't necessarily hear the effects of it. You just don't get the output you would otherwise get if you had the right size port. Here is a port area calculator that can help you determine just how much port area you should have based on how much power you are going to be running: https://docs.google.com/spreadsheets/d/1mwBK02mF-8BF3mxqqB8WG0H0GUbTmgQfpJODlo_0moQ/edit?usp=sharing Depending on how much power you were running, your port area may have been just fine. If you were running higher power you might have been very surprised to find out how much more output you COULD have had with a larger port.
  3. There has been a big update to the port area calculator! SMD member aaricchavez has taken my spreadsheet and used his vastly superior google doc skills to make the spreadsheet a lot more visually appealing and easier to use! Big thanks out to him for his efforts. Everyone please use the new link below! Here is the new link: https://docs.google.com/spreadsheets/d/1mwBK02mF-8BF3mxqqB8WG0H0GUbTmgQfpJODlo_0moQ/edit?usp=sharing
  4. No problem with having the ports sticking out of the box. As long as you don't mind how it looks it will help preserve some of your internal volume.
  5. You will see an increase from making the front chamber larger. Will it be noticeable to the ear? Probably not. Will it be measurable on the dB meter, probably yes.
  6. I would use two 4" ports, they are going to have to be about 30" long each, they are going to take up about .5 cubes of internal space and that's still not going to get you quite to 27 Hz. Making them any longer to try to get to a 27 hz tuning is just going to take up even more box space. For future reference, you REALLY need to know how you are going to do your ports before you start cutting wood. Adding ports after the box has already been built almost always results in difficulties.
  7. How much power are you going to be running?
  8. Lowering the tuning frequency will give you better low frequency output, at the expense of higher frequency output. Its hard to say if that is going to be what you want without hearing the system first. My suggestion would be to make the port removable or otherwise adjustable so you can play with the tuning frequency once you get the system playing. What you are describing for using 1/2" material for the port and sliding it into the box would be considered a slot port. It would be a 2 common wall slot port. While you can use 1/2 material for the top and bottom of the port, I would strongly suggest using 3/4" material for the sides of the port since they will be unsupported.
  9. The subs he has don't have huge Xmax, if he runs any more power than the amp he has is likely to put out, he will probably have issues with over-excursion.
  10. As far as your box specs go, those look pretty good. The subs you have should perform well in a 4th order bandpass box. The only change I would make would be to increase your port area. I would shoot for 200 sq in of port area. Since all the output comes out the port on a bandpass box, they are very sensitive to port noise and port compression. As far as meeting your goal of getting loud and low, things get more iffy. The box will certainly get loud, however like most ported boxes, you are likely to get your max output around the tuning frequency and bandpass boxes are tuned higher. Here is a graph showing the raw output from both your intended bandpass box (in red) and a 8 cu ft ported box tuned to 32 hz (in green). Please note this graph does not include the effects of cabin gain, which will boost low frequency output significantly. Cabin gain should boost both enclosure's output roughly the same so the comparison is still valid. The ported box is probably going to have more output between 35 Hz down to around 25 Hz. The bandpass will do better above and below that range.
  11. Yeah, I do. But I'm really slow these days. I looked at your box specs, in my opinion you are low on port area, but not hugely so. How loud do you think you should be getting?
  12. What are the specs of your current slot ported box? There is nothing aero ports can do that slot ports can't, so there is absolutely no guarantee that going to an aero port box is going to do a damn thing for you. It may just be that you have a poorly designed box.
  13. If you don't know anything about them, why do you want a 4th order bandpass box?
  14. A ported enclosure will give you the most low frequency output 99% of the time.
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