TLDR= Hello Everyone. I know this is too much information just for an enclosure question, but I feel it was necessary in order to explain the design choice. My actual question is at the end. Regarding turbulence/resonance/avoiding absolute garbage sound.
I have a 1999 Chevy k1500 Suburban and would like to make a ported box for where the spare tire goes on the inside. I would like to recess the subwoofer into the box and cover it with a protective cage, as it is an SUV at the end of the day., and don't want a nice hole in my woofer . I am also going to be designing a "raised floor" around the box, for the cargo area with some drawers so I can keep tools and such on hand, but still have usable room in the back. Ideally, I would like to wrap both the box and drawer system with OEM style, matching carpet so they don't look out of place.
I started playing around in CAD and I think I have found a design that might work? I tried to smooth out the pathway and design it to be made with 2 layers of 3/4inch, so 1.5 inch total wall thickness. The subwoofer mounting side endcap, would probably be a little thicker as I would like the subwoofer as recessed as possible.
QUESTION=
I'm not too sure on the porting of the box. I saw some models showing resonance in various shape boxes, and unfortunately was unable to find something that I feel would translate. I have the internal volume calculated according to the sub spec sheet. However, I did not factor in the displacement of the woofer itself but that's minor details. In an attempt to reduce turbulence, the end of the port is slightly flared out, and rounded so there are no edges, on the interior except for the endcaps which would just be sandwiched on. My question is, conceptually, would the shape of the box/port work? I would really appreciate some technical guidance. Thank you
I have a 1999 Chevy k1500 Suburban and would like to make a ported box for where the spare tire goes on the inside. I would like to recess the subwoofer into the box and cover it with a protective cage, as it is an SUV at the end of the day., and don't want a nice hole in my woofer . I am also going to be designing a "raised floor" around the box, for the cargo area with some drawers so I can keep tools and such on hand, but still have usable room in the back. Ideally, I would like to wrap both the box and drawer system with OEM style, matching carpet so they don't look out of place.
I started playing around in CAD and I think I have found a design that might work? I tried to smooth out the pathway and design it to be made with 2 layers of 3/4inch, so 1.5 inch total wall thickness. The subwoofer mounting side endcap, would probably be a little thicker as I would like the subwoofer as recessed as possible.
QUESTION=
I'm not too sure on the porting of the box. I saw some models showing resonance in various shape boxes, and unfortunately was unable to find something that I feel would translate. I have the internal volume calculated according to the sub spec sheet. However, I did not factor in the displacement of the woofer itself but that's minor details. In an attempt to reduce turbulence, the end of the port is slightly flared out, and rounded so there are no edges, on the interior except for the endcaps which would just be sandwiched on. My question is, conceptually, would the shape of the box/port work? I would really appreciate some technical guidance. Thank you
Attachments
Looks awesome and similar to a snail shell that I have been tying to model. A project close to my heart! Have you entered your volumes into Winisd and HR to see what they both say? I have been going nuts with this and the resulting graphs were interesting enough to turn the bass reflex into a TL. I am aiming for a 43hz tune and reducing cab volume as much as possible. So my port spiral is tapered to a narrower exit than its coupling. Driver volume is also a spiral and again tapers from wider under the driver to port coupling. In Winisd this I input as a ported bass reflex and in HR as a pipe
I think you will do well with your cab shape. The panel curvature is great for rigidity, and the spiral wall doubles as bracing. The path looks good too. I am not sure if I like the port to be on a different plane to the driver, though. I like the sound of ported, and to me in the same plane as the driver sounds cleaner. Especially when playing the bass note by note solo
Allow me to recommend capping the end of the port flare and exiting it from the face by turning it around 90 degree there. Another suggestion that I have is to not have the faces on a parallel plane. Inclining the faces so that the exit side is closer to each other will also give you a tapered pipe and stop the woofer from firing directly across to the opposite flat side of the vehicle. This would be different from what I am making, I am turning the woofer around instead by placing a pod on the face so that the woofer and port are in the same plane and more overall snail shape
My build will be a strip of marine PVA foam board wrapped in the spiral and 200gsm biax stitched glass cloth on either side as skin. Same with the faces. This structure will be better than one that can be made from any wood based, and I will highly recommend that you consider that for your build too
Regards
Randy
I think you will do well with your cab shape. The panel curvature is great for rigidity, and the spiral wall doubles as bracing. The path looks good too. I am not sure if I like the port to be on a different plane to the driver, though. I like the sound of ported, and to me in the same plane as the driver sounds cleaner. Especially when playing the bass note by note solo
Allow me to recommend capping the end of the port flare and exiting it from the face by turning it around 90 degree there. Another suggestion that I have is to not have the faces on a parallel plane. Inclining the faces so that the exit side is closer to each other will also give you a tapered pipe and stop the woofer from firing directly across to the opposite flat side of the vehicle. This would be different from what I am making, I am turning the woofer around instead by placing a pod on the face so that the woofer and port are in the same plane and more overall snail shape
My build will be a strip of marine PVA foam board wrapped in the spiral and 200gsm biax stitched glass cloth on either side as skin. Same with the faces. This structure will be better than one that can be made from any wood based, and I will highly recommend that you consider that for your build too
Regards
Randy
Just my 2 cents, and this assumes you are doing a typical subwoofer that will cross in the neighborhood of 80-ish Hz. Obviously some people like to optimize things, build tank-like enclosures, make complex shapes, etc. so take it with a grain of salt.
This is overkill in my opinion. Cars are a brutal, rattly, noisy environment. Making a super stiff enclosure is of limited value. Also, typical size boxes will have panel resonances that are significantly higher than what a subwoofer plays, so they won't normally be excited anyway. I've been involved in a couple builds that filled the entire rear of a vehicle and never had any audible issues using 3/4 inch MDF.
Similar issue as above. Most internal and port resonances will be above where the subwoofer is going to play. Model the box with something that gives you port velocity. Most suggest that a value below 17 meters/second produces no appreciable port noise due to turbulence.
Bass is omnidirectional at these frequencies and has very long wavelengths. Port location, port orientation, woofer orientation, etc. will have minimal influence given the overall enclosure size in this case.
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I have a similar cabin type in my XV. System is all JL Audio based. Playlist is heavy with Robbie Shakespeare on the electric bass. Bass guitar notes are all over the place and sounds weird coming from the side doors. Having my sub facing rear and behind the right rear passenger seat is the most listenable position. In my last car, a Holden SV8, the woofer sounded best firing from the ski port. Away from the paper, the position of the sub does seem to make a difference
I will make another point. Speaker cabs are not furniture and should not be built as such, even though wood products are used. A speaker box is a vessel with a powered engine and should be built to be that. Even furniture made for powered vessels are built differently. What an engine introduces for speakers are the panel resonances, and I hope that you realise that even the best of plywood is not considered a complete construction material. I should start a thread on fibre reinforced plastic sandwich construction, as this approach can be used for static powered vessels to mobile. In other words, ply over PVA foam sandwich to glass/carbon/Kevlar matrix over PVA foam and will be superior in every way to even the best braced wooden board cabinets. Its only a recommendation and does not have to be taken man
Thanks sick. No I haven't used WINISD or HR, the links that I found looked kinda sketchy so I didn't try it yet. I just used the body fill command to find the internal volume, haven't used any simulation software yet. What links to the software do you recommend?
How much of an improvement would it be over some Baltic Birch? That is what I was planning on building both my box and drawer system out of, and then maybe spraying\sealing it with the Soundskin coating, or some sort of Rhinoliner spray on material.
Yeah, I feel like it is overkill as well, but based on the sub I'm trying to stick in there I feel like it is better to be overbuilt than underbuilt. The subwoofer in question is a DD Audio 712F, so a true 1500W RMS and 4500W Peak. Currently I'm running a Pioneer Champion Series 12 at only 600W and that thing knocks pretty hard even being "underpowered." Couldn't Say what the volume of that box is, but based off of the spec sheet the desired volume is pretty close.
By "noisy" do you mean noise as in vibration, or noise as in electrical interference? Either way, I totally agree. I have a roll and a half of some Soundskin pro in each door, triangulated foam speaker backing and sound rings to really keep the sound from leaking out, and it definitely sounds more full. This summer I will hopefully strip the whole interior and coat with liner, deadening, and some insulating foam under the carpet/headliner as well as behind the side furniture pieces. Dash will be pulled as well, as I have a dash pocket to install in place of the passenger airbag, so the underside of the dash can also be sound deadened.
What software should I use? do you have any links?
Somehow it sounds best there. It's a JL box with a side port and the xover is set at 150hz. The port mouth is about 20cm from the inner wheel arch cover. The worst offender is the bass guitar coming from the door speakers. I have a mixer attached in front of the poweramp and regularly plug in the bass guitar too. None of my issues are a real issue with things like rock and house music
At some point I will 3D print some pods for the doors and fit one of the 6.5" OEM driver that I am expecting in a 4L volume 4hz ported box that I am working on and mess with angles. A pair of those 3.5" FR right next and another pair up at the A pillars. Around 300hz xover for them and dropping the 10" in the boot to about 80hz should get me humming to the basslines nicely.... this is getting off track though
I did a search for the software and downloaded from their home website
Massive improvement. I have recently been messing with 10" subs in the 1kwrms class to pick two different price point ones. Its not just the strength but the stiffness that goes up with the sandwich process and this is what helps. How about this, if you were to build a housing for a high performance small jet, would you do it with baltic birch or FRP sandwich? West systems website documents will be the best place to start for this process
The finished substrate will be an epoxy impregnated fibreglass surface. This is a great surface for coating as it can be easily made water break free. I will be using around 10mm foam with 200gsm stitched glass skins eventually for one 10" in the car in a wedge in the current position. This one will be a TL
I currently have a rectangular box with the sub facing the passenger side window and the port facing the driver side window, centered in the cargo area What's nice about Suburbans is that its a box inside a box so you get quite at more out of a smaller sub. At least what I noticed compared to my friends builds inside normal sedans.
And I was thinking the same thing with the offset driver position but I've seen a few other builds. The picture attached is one that I really like. And funny enough they used DD woofers too.
I like Hornresp, super flexible program, and great support here on this site.
http://www.hornresp.net/
Conceptually the shape of the box/port is no problem.
How are you planning to make the curves from Baltic Birch?
Where is the spare tire going to go?
We are talking about two different things. Of course moving the sub around significantly in the entire interior volume can make differences. Moving the port a matter of inches on an enclosure in a fixed position is a different scenario, and will make minimal difference in my opinion.
And I specifically said a typical sub crossed over at around 80 Hz. You're talking nearly double that frequency.
I meant noise as in general background sound. In a car the noise floor is so high that in typical cases any enclosure resonance is going to be far below engine noise, road noise, random panel noise, etc.
In a true multi-thousand watt driver application, things get more complicated. I specifically said earlier "a typical subwoofer," because those details were left out. Extreme power situations have their own requirements. I'm not a fan of those kinds of systems for general use, so they're not what I'm involved with. So at this point, I'm bowing out of the discussion.
My PC is making every attempt to block it. Is there a more secure download spot? I'm just scared to run it lol.
I have a table saw so I was going to do spaces out cuts and cut them at an angle, then come back over those cuts and hit the angle the other way. Maybe a little bit of steam to keep it from cracking, but I don't want the wood to swell. My father is a carpenter/woodworker and he will most likely help me with the whole process. I also could probably just make good prints and take it to a cabinet shop to have them build it for me if I want to. I mean they have more fancy tools than I have. I do like in the San Francisco Bay Area so I could try to hit up Bobby Gately or Steve Meade and see if they can build my design. Last time I talked to Bobby to get a quote it was starting $1600, his design. So probably a front port like the DD picture I posted.
My suburban is lifted on bigger tires so the spare is useless. Stock tire is like a 8.5 or 9.5 wide 31, I have 12.5 wide 33s with some offset now, so a spare wouldn't fit if I tried. I am going to be adding an onboard air system eventually too, so I will keep tire patch equipment on hand along with sockets, wrenches, straps, come along etc
I'm going to have to look into that. I don't have any experience with anything but wood for boxes. I need to see some pics though, sounds like it's going to be sick.
Lol yeah I'm fully aware. Box will be fully carpeted inside and out, and all tools will be stored separately and tightly in tool rolls. Rolls will be secured from moving around themselves. Some heavy duty hinges and good locks to keep the box itself from making noise. I could even sound deaden it too just to be overkill. Weight isn't an issue for me, I just want it to be solid.
Your antivirus software is generating a false positive.
Rest assured, the Hornresp Setup.exe file is perfectly safe downloaded from the site linked by Art (weltersys).
I'm just scared of downloading from an http instead of https. I'm just going to really research that link before hitting download. I'm not doubting your integrity, I'm just crazy and overthink things.
Hornresp is very kindly hosted on a server in Germany by diyAudio poster Sabbelbacke. I have no expertise in such matters, and if it was not for Sabbelbacke there would be no Hornresp to download. The Hornresp Setup.exe file that I generate will NEVER contain malicious code. As I understand it, for the file to become a threat it would need to be somehow intercepted and hacked as it was uploaded by me or downloaded by a user.
Nothing like that David, just we are familiar, but new users might just pass, and never join the board either. I have passed up on a number of downloads after taking heed of a browser security alert. Having been on the board for a while and being familiar with the program was the only reason I pushed download anyway. If I hadn't been on the board, I would have also passed
Hi Randy,
Understood.
I have sent an email to Sabbelbacke to make him aware of the situation. I am not sure that there is anything he can do to make things better for us though. I am just very grateful that he was prepared to host Hornresp in the first place.
Coincidentally, just today I have released yet another update
.
https://www.diyaudio.com/community/threads/hornresp.119854/page-707#post-7559338
Kind regards,
David
Understood.
I have sent an email to Sabbelbacke to make him aware of the situation. I am not sure that there is anything he can do to make things better for us though. I am just very grateful that he was prepared to host Hornresp in the first place.
Coincidentally, just today I have released yet another update
.https://www.diyaudio.com/community/threads/hornresp.119854/page-707#post-7559338
Kind regards,
David