Quasi-Sixth Order Series-Tuned Bandpass

[keep_hope_alive Premium Member]

you'll have to find a spot for the amp. take the time to screw it in place, loom the wires, and route it well and logically. you want the amp out of the way so you can easily move/rotate/flip the box. hopefully the wires you have are long enough to do that.

when you face it forward, you'll have to make filler panels for the sides and top. that box is blocking a lot of airflow to the cabin. facing them backwards you are going to lose a lot of bass out of the car, that will never make it to your headrests.

 

[murph 10+ year member]

you'll have to find a spot for the amp. take the time to screw it in place, loom the wires, and route it well and logically. you want the amp out of the way so you can easily move/rotate/flip the box. hopefully the wires you have are long enough to do that.
when you face it forward, you'll have to make filler panels for the sides and top. that box is blocking a lot of airflow to the cabin. facing them backwards you are going to lose a lot of bass out of the car, that will never make it to your headrests.

That is not my current setup... My wiring is cleaned up and my amp is mounted... I was using that as reference to trunk size.

 

[keep_hope_alive Premium Member]

so how is the amp mounted?

 

[murph 10+ year member]

so how is the amp mounted?

It is mounted on the 1/3 pull down seat.

The sound issues have been fixed with some eq tweeking. The box is very sensitive to over amplified or clipped music. If a song is either or I have to turn the volume down a bit to get it sounding right again. (only a hand full of songs)

 

[keep_hope_alive Premium Member]

ok. seat mounting is fine, just be sure if you turn the box around that the surround doesn't touch the amp chassis.

the 1/3 seat is usually driver's side. so if you flip the box around the port is on the passenger side.

to seal it off you can just flip it around. use cardboard to mock up the filler panels, cut them out of 3/4" MDF and experiment with them taped to the box and car.

 

[iamamp3pimp 5,000+ posts]

The build looks like it came out fantastic. do you have access to a TL?

I'd like to see comparisons between this enclosure and a standard ported one.

 

[ancorp 10+ year member]

The box is gorgeous. But - what's the difference between this and a regular ported box? I wanted to do something like this for a while with a 15 or a 18 in my trunk, firing up inside the box, and sealed off into the cabin.

 

[T3mpest 10+ year member]

2 difference resonance points and barely and octave of response..... K

 

[Moble Enclosurs 10+ year member]

Hey guys! Justy wanted to chime in here and answer any questions about this build. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif. It was not easy to get that response considering we were required to stay below 3.5 cubes, but all in all I hope it worked out well, and as far as it having two resonances, that is incorrect, and the octave band is around a full octave, which is not bad for a BP design. The goal we had was an SQL to play around the 20-60Hz range, and the first idea was to utilize a 4th order, but I found that this design style worked a bit better than that as far as output in the lower region.

The design was goaled for an in trunk install, BUT the point of interest on the location of the port was to be facing the cabin, which may or may not have been mentioned lol. But all in all, the resonances in the upper range can very well be fixed by sealing it off, though a lot of this has to do with the end of band operation froma lower tuning and trying to control the phase within a small dimensional space given that quasi 6th orders can require a lot of room. All in all, I stuck with a BP design by request of the customer and though a conventional ported box would have worked very well also, the idea was to crush the lows in this case, with high efficiency, and the way to go with that while keeping control of the driver is with a BP.

That all being said, Im glad that an honest review was done and I am glad that the enclosure came out well! The muddiness mentioned can be tweaked obviously by cutoff points and possibly positioning as the response information was based on a single position alone, so please @Murph keep me updated on that and thanks @keep_hope_alive for the help on that as well! If you have any questions, please let me know //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

 

[Moble Enclosurs 10+ year member]

The box is gorgeous. But - what's the difference between this and a regular ported box? I wanted to do something like this for a while with a 15 or a 18 in my trunk, firing up inside the box, and sealed off into the cabin.

Thanks, and the main difference is the control and efficiency. These quasi designs, which can also be referred to as tapped designs depending on the physical structure, can have great efficiency for the use of lower powered amplifiers. This one in particular was designed around a 500W output. SO, for its output on 500W, I hope that it did its job in that respect. But with the control, the great thing is that the compression can be made quite large for lower tuning capabilities, but still control the excursion from the cross-sectional area of the port along with its length. The longer the port (to a point), the better the coupling with the drivers mechanical parameters in relation to tuning of the compression area and beginning of the line. Other than that, in a lot of cases, which this cannot be argued, a typical ported box can very well give a greater response band. But with that, less control in the lower region as well as a possible high peak in the response (though that can easily be controlled by eq settings as well-since they are to be lowered and not raise) from certain drivers designed for SPL purposes. I hope that helps answer a little bit about it. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[Moble Enclosurs 10+ year member]

Those with doubts or concerns need to understand that this particular design was based around the request of a bandpass-originally a 4th, and within a limited volume for BPs as a total volume---hence the quasi effect being utilized. That has to be taken into consideration when you judge its limitations.

 

[murph 10+ year member]

Hey guys! Justy wanted to chime in here and answer any questions about this build. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif. It was not easy to get that response considering we were required to stay below 3.5 cubes, but all in all I hope it worked out well, and as far as it having two resonances, that is incorrect, and the octave band is around a full octave, which is not bad for a BP design. The goal we had was an SQL to play around the 20-60Hz range, and the first idea was to utilize a 4th order, but I found that this design style worked a bit better than that as far as output in the lower region. The design was goaled for an in trunk install, BUT the point of interest on the location of the port was to be facing the cabin, which may or may not have been mentioned lol. But all in all, the resonances in the upper range can very well be fixed by sealing it off, though a lot of this has to do with the end of band operation froma lower tuning and trying to control the phase within a small dimensional space given that quasi 6th orders can require a lot of room. All in all, I stuck with a BP design by request of the customer and though a conventional ported box would have worked very well also, the idea was to crush the lows in this case, with high efficiency, and the way to go with that while keeping control of the driver is with a BP.

That all being said, Im glad that an honest review was done and I am glad that the enclosure came out well! The muddiness mentioned can be tweaked obviously by cutoff points and possibly positioning as the response information was based on a single position alone, so please @Murph keep me updated on that and thanks @keep_hope_alive for the help on that as well! If you have any questions, please let me know //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif.

After lots of tweaking I am quite happy with the box. From 26-36 you would think there is a decent 15 in the trunk or possibly even 2 12's. I forgot to shoot a video but, man I am impressed. It plays the bass guitar very well and sounds very clean. I found the low end output to be better when facing the trunk.

 

[Moble Enclosurs 10+ year member]

After lots of tweaking I am quite happy with the box. From 26-36 you would think there is a decent 15 in the trunk or possibly even 2 12's. I forgot to shoot a video but, man I am impressed. It plays the bass guitar very well and sounds very clean. I found the low end output to be better when facing the trunk.

Sweet man! Thank you for the extremely quick response! lol. Im glad you like it. Now, regarding the positioning, the ideal for it being facing the front was to control the upper range, which had some to do with that hollowing you mentioned before, but naturally facing the trunk it will excite the low frequencies even more, so either way I am very happy for you! Thank you also for the honest review and I am glad I had the chance to give you a great box that was very complex to design lol. I had very much fun with it! If you need anything in the future, please let me know man. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

To the others, I do hope that my explanations helped a bit on understanding the limitations we were working with and that the understanding of the idea of that type of design definitely is a tough one as you all mentioned lol, but all in all a great way to gain low end efficiency!

 

[murph 10+ year member]

@Moble Enclosurs Just wanted to let you know the box pulled off a 137.4 sealed at the dash.

 

[Moble Enclosurs 10+ year member]

Was that a musical average or at a specific frequency? Not bad for a single 12 on 500w designed for music.