Xcel 7 Report post Posted January 8, 2016 (edited) After solving my previous issues involving the subwoofer in my E36 I now have another problem, the box is sliding around in the boot with my "spirited" driving which is not a good thing. I've thought of strapping it down with a ratchet tie down hooked between two holes already in the floor of the boot. A more elegant option would be to bolt it to the floor of the boot with L brackets but I'm not sure drilling down there is such a good idea.What should I do? Edited January 8, 2016 by Xcel Quote Share this post Link to post Share on other sites
Neal 544 Report post Posted January 8, 2016 If you have fixed rear seats put four m6 rivnuts into rear firewall. Make or bent brackets to suit between subbox and back seat. Drill from inside of car (back seat clips out easily) to make sure you don't go too low and hit fuel tanks. Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted January 8, 2016 I have folding rear seats so that probably won't work for me. Fortunately I can let more bass through if I want by folding them down though haha.It looks like the gas tanks probably aren't an issue if I'm drilling into the chassis as long as it's not too far back but I'm also concerned about starting rust doing that. Quote Share this post Link to post Share on other sites
Ahmedsinc 414 Report post Posted January 9, 2016 Epoxy a couple of bolts to the floor. Avoids driving into something you ought not to have drilled into and eliminates any chance of the holes rusting Quote Share this post Link to post Share on other sites
MD13 494 Report post Posted January 10, 2016 A little basic but I bolted L shaped brackets to the sub box then cable tied these to the child seat mount brackets in the boot. This way I can easily remove the sub box to get at the spare wheel. L brackets were available at Mitre 10 in the fencing section I think. Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 10, 2016 By far the cheapest and easiest option is to cover the bottom of your sub box in a roll of wide adhesive Velcro tape, securing with a couple staples, use the spiky side only. Works like a charm I get no movement whatsoever although i have a touring with solid boot floor panels. If your carpet moves just secure it with Velcro too. Quote Share this post Link to post Share on other sites
huff3r 347 Report post Posted January 10, 2016 With folding seats make sure you secure it properly, velcro might not be enough, as it will be considered an unsecure load when it comes to WoF time. I was advised this when I had my Subaru, same as spare wheel needing to be secure, and not an issue where seats don't fold down . Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted January 10, 2016 ^^ really what about when you take your car for a WOF and leave kids push chair, drink bottles etc in the car Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 10, 2016 With folding seats make sure you secure it properly, velcro might not be enough, as it will be considered an unsecure load when it comes to WoF time. I was advised this when I had my Subaru, same as spare wheel needing to be secure, and not an issue where seats don't fold down . It prevents it moving around in the boot which is what he wants. Some WOF agents are very enthusiastic with their interpretation of the NZTA Wof "regulations" Had my sub box setup as it is with folding seats for around 10 Wof inspections now, none of the indians at AA or VTNZ noted anything regarding it. Quote Share this post Link to post Share on other sites
huff3r 347 Report post Posted January 10, 2016 It prevents it moving around in the boot which is what he wants. Some WOF agents are very enthusiastic with their interpretation of the NZTA Wof "regulations" Had my sub box setup as it is with folding seats for around 10 Wof inspections now, none of the indians at AA or VTNZ noted anything regarding it. Ahh, sorry my memory has me fooled. It was the WoF inspector commenting on how spare tyres have to be secured if the seats fold down, but sub boxes don't and how silly it was. I never secured it decently in my Subaru but stopped it sliding with some measly brackets. With that in mind, Velcro is quite a good idea actually. Will keep in mind when I eventually get a new sub. Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 10, 2016 Ahh, sorry my memory has me fooled. It was the WoF inspector commenting on how spare tyres have to be secured if the seats fold down, but sub boxes don't and how silly it was. I never secured it decently in my Subaru but stopped it sliding with some measly brackets. With that in mind, Velcro is quite a good idea actually. Will keep in mind when I eventually get a new sub. I'll keep that point in mind next time the wof dude gives me sh*t about a 2cv with an insecure spare wheel eghhhhhh. I think Velcro is great as i often need to take it out to access the lock bolt key and spare wheel. No farting about with a screwdriver. If you wire a plug into the harness it becomes a very simple proceedure to remove and refit. 1 Quote Share this post Link to post Share on other sites
scottbeattie 63 Report post Posted January 10, 2016 I'll keep that point in mind next time the wof dude gives me sh*t about a 2cv with an insecure spare I didn't think you could build up enough speed in a 2cv for the spare wheel to become a dangerous projectile in a crash! Sent from my iPhone using Tapatalk Quote Share this post Link to post Share on other sites
Andre3000 55 Report post Posted January 10, 2016 I didn't think you could build up enough speed in a 2cv for the spare wheel to become a dangerous projectile in a crash! � Sent from my iPhone using Tapatalk If the trade winds are favorable it is possible 2 Quote Share this post Link to post Share on other sites
zero 1162 Report post Posted January 10, 2016 I know you can fail wof on an unsecured battery. Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted January 10, 2016 I have it secured with a ratchet tie down at the moment but I like the idea of epoxying some L brackets down for a more permanent solution. It's a small but relatively heavy box at 35kg so I hope it doesn't break free. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted January 10, 2016 ^wow taking up that much room would drive me up the wall Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted January 11, 2016 I don't use my boot for anything else so it doesn't bother me. I could move it back another 25cm if I wanted to but that was where the existing holes were for the strap. Quote Share this post Link to post Share on other sites
Neal 544 Report post Posted January 11, 2016 When I suggest m6 rivnuts scratch that. Use m12 grade 8.8 fasteners and weld in the L brackets ! That a 15 in a 2.5 cubic foot box ? Quote Share this post Link to post Share on other sites
MD13 494 Report post Posted January 11, 2016 That is a big sucker! What happens when you get a flat tyre? Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted January 11, 2016 It's actually quite a small custom enclosure (1 cubic foot) with most of the space taken up by a very long slot port I designed using the Thiele/Small paramaters in a calculator online. The sub has a very low Vas (26L) due to the stiff spider so that's probably why it wanted such a small enclosure, either way it goes really hard and seems to have great sound quality (aside from interior rattles at high volume). It's an Ascendant Audio Havoc 12 inch rated at 1250w rms but I have 1800w available, probably limited by the stock alternator currently though.If I had it bolted to L brackets right to the back of the boot I shouldn't have any trouble getting the spare tyre out. Quote Share this post Link to post Share on other sites
tawa 150 Report post Posted January 11, 2016 A little basic but I bolted L shaped brackets to the sub box then cable tied these to the child seat mount brackets in the boot. This way I can easily remove the sub box to get at the spare wheel. L brackets were available at Mitre 10 in the fencing section I think. What? Child seat goes in the boot? Guess it's one way to cut down on cabin noise, those crazy germans... When I suggest m6 rivnuts scratch that. Use m12 grade 8.8 fasteners and weld in the L brackets ! That a 15 in a 2.5 cubic foot box ? Which will be the only four boits left in the car after everything rattles off... Just dip it in a sikaflex/loctite shandy, that'll keep everything together! 1 Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted January 11, 2016 Which will be the only four boits left in the car after everything rattles off... Just dip it in a sikaflex/loctite shandy, that'll keep everything together! Haha I've already had a few bolts come loose, there was a battle in the boot between the amplifiers and the inferior one lost. I found it's mounting plate hanging by only one bolt. Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted February 4, 2016 Intrigued to see how you came up with 28 litres for the volume? here is a snip the curve rolling off at 200Hz is 28 litres the other one is 10.9l which gives a 'Q' of .7071 which is "optimally" flat response The driver is a lardy 250 gram cone must flop all over the place in a 28 litre box? You might have the parameters of the new version of the Havoc but these are the ones I used: Fs: 30.9Hz Qms: 6.07 Qes: 0.43 Qts: 0.4 Mms: 238g Sd: 480cm^2 Vas: 26.1L Bl: 19.8 tesla meters Xmax: 30mm RMS: 1250W I tried a few different calculators with similar results including WinISD and they all suggested an enclosure roughly the same as the Vas with a ~1.4m port tuned to ~31hz and I think it works well, I wouldn't say it flops around at all. From my understanding it's stiff suspension helps control it in such a small enclosure. I have a low pass filter set up to prevent over-excursion below 30hz and then adjusted gains to make sure it doesn't exceed the Xmax since I have more power than it needs available. Whenever I simulated recommended boxes they ended up being too peaky which might be nice for SPL competitions but that's not really my thing. Quote Share this post Link to post Share on other sites
Xcel 7 Report post Posted February 5, 2016 (edited) What are you using to model it? My enclosure is actually only 23.1L after re-measuring it. As far as I know the enclosure Q or Qtc of 0.707 was only for sealed enclosures whereas ported use an alignment e.g. SBB4, QB3 or SC4. Are you sure you're modelling a ported enclosure? Edited February 5, 2016 by Xcel Quote Share this post Link to post Share on other sites
Olaf 3317 Report post Posted February 5, 2016 ported subs are the work of the devil! sealed box is faster and more tuneful! #8 ) Quote Share this post Link to post Share on other sites
