... The Hijet is pretty noisy, isn't it! There's a lot of road noise. ... at 40 - 50km/h on a sealed road the road noise muffles the stereo so much it's hard to hear what's being played. But I don't want it very loud. I put door speakers in and glued a couple of small speakers above and behind the head-rests for my modest MD/CD/radio. It sounds very tinny when stationary with the small speakers and it sounds awful when I'm moving. - So what to do? I thought the road noise can only get better if I put something on the painted metal surfaces which make the bottom of the cab. It's got floor mats - with a scrap of 'carpet' underneath, and that's all. - So I intend to stick some tough rubbery-plastic-backed carpeting where I see the white paint. Has anyone done this? I suppose I'll be well advised to unbolt the seats and try to do a thorough job, eh? As for the sound quality of the stereo and speakers, I'm favouring leaving the small speakers in place and trying to get the full range of sounds (esp the bass) by strapping one of these:-to the back wall between the (stock) seats. ( http://minkara.carview.co.jp/userid/617723/car/526873/2565777/parts.aspx ) I just want a decent sound. I'm not trying to win any competitions for the best stereo in a Hijet. But I MUST have some bass. What do you guys do when you want better sound from your car audio? And any advice on deadening the road noise successfully?
Well there is a product called "Dynamat" http://www.dynamat.com/ , but for me... it's far too costly to be on my list. I'm anxious to hear from anyone how to drop sound levels in my cab without having to go to this expense. z
I got mine quite a bit quieter by doing the following. Remove the door panels and spray several layers of rubberized undercoating inside the door shells.Remove your seats,carpets and floor mats,and spray a few layers of the rubberized rocker undrcoating on everything including the front footwell (helps keep the heat in in winter as well).Spray the inner fenders above the front wheels as well.The factory thin plastic covering the seat area and floor is best used as a template to cut some rubber backed carpet to replace the factory plastic..The rear cab wall is next on my list to be covered,but even without it there is a huge difference in noise.
Good tips fupa... I do have a single layer of ruberized on the floor... I happen to have a couple of cans left, I think I'm gonna do some more spraying tomorrow and see if I can't make it quieter yet. I personally don't agree with floor mats in a "rough service" vehicle... they just seem to trap stuff under them and cause rot.. I use rolled drainage mat that we used to have in army field showers (I had rolls of this... sold it all at marina yard sales tho now... cept a few scraps), no... I didn't scoop the used stuff.. I had new rolls Now when I want to clean the mud out of my cab, I pull the mats and gently hose off the floor of my truck (avoid water spray under the dash ). I did the same thing for the entire floor of my 76 blazer (after I rebuilt it) and never had a lick of the ol nasty rust. I'm going to take the stereo issues over to my buds at diyaudio.com and see what the engineers there can figure out for small and effective, I simply can NOT justify paying for a kenwood tune up sub. I'm sure I can put something suitable together from bargain parts at www.parts-express.com z
Stuff you got a diesel clakker in that rig of yours don't you? Can ya hear the .. um.. radio (can't call a single a stereo right? ) when the engine is running? z
As a rule ..unless you are a complete audiophile speakers don't matter as much as the placement and enclosure...kinda like the way Dire Straits "money for nothing" sounds good on any stereo,and even the cheapest earbuds sound pretty damn good..I have seen $20 3 piece computer speakers (left right and sub)in a car that sounded fairly decent...for a fun experiment take a clock radio and turn up the volume and give it a listen...then place it inside a plastic pail and note that it sounds 10x better....A bose wave radio gets amazing sound just because it has a well designed twisted chamber behind the speaker...prob. wouldn't be hard to replicate with pvc pipe and a small woofer..then it could be mounted anywhere,even up under the dash...
Rubberised undercoating? I'll have to do another check. I can imagine what it is but I can't think which section of the DIY centre I'd best look at. I thought the inner fenders would be a good place to try to soundproof as well - that's where most of the road noise is coming from I reckon. I installed the tune-up sub, and it has vastly improved the sound - but it booms a lot. I imagine I'm hitting the resonant frequency of the back wall of the cab on a lot of the bass tones. I realize I'm not going to get a sound like I would in a car. One of the problems is the 10cm max speaker holes in the doors. Yes, I could cut it out more, or I could use spacers for either wider speakers, or longer ones such as those from better quality domestic stereo speakers. And in fact I was testing a whole bunch of speakers I have amassed on my bench last night and I found a pair which sound much better than the car-speakers I have in it now. The speakers that seem a good replacement are still 10cm, but they have a long 'stroke.' - It's a pain to make spacers, but I'll try I guess. I'll use one or two discs made from 11mm 'cement' board and cut it with my scroll saw. - Then I'll probably spray it with something matt and black - like exhaust paint. At least I can go about 40 to 50 km/h and still be able to tell what music I've got on.
I must've spent a total of three hours reading about that stuff and reading what the people have to say about it. It's probably a good idea. But it's pretty expensive and I don't think it will help much based on the sum of what the people said about it. It'll do something for the resonance and the knocking but it won't do much for the road noise. And it's the road noise which is the biggest problem.
Yes. It's a lot of money to shell out for a non-essential item. But it is a quick fix. It wasn't easy installing the Kenwood. It was a tight fit (a perfect fit actually). But I had to bend the four mounting brackets to make the unit stick out an extra centimetre because it was just a tad too long to fit in the recess between the back window bottom frame and where it curves up from behind the seat. I managed to break a couple of the nuts and bolts I used and cursed the cheap quality of expensive stainless stuff. I actually overtorqued one screw out of the eight which go into the back of the unit to mount the brackets. But seven viable nuts is enough I think. The wiring wasn't difficult. I cut the wires as short as possible and put new connectors on them. I ran the wires along the central plastic cover on the driver's side and made it neat with wire ties. The wired remote wire is far too long and I'm going to put it on the bench, cut it to the right length and resolder the connections inside the controller. Well I'm quite pleased because after several hours I got the whole thing working, and I'm not unhappy with how it looks. I'm going to take a snap of it and I'll post it once the missus shows me how to upload pics to my blog.
I'm not chucking the stock radio out. It works fine as a radio, and the road noise didn't stop the sound from the onboard speaker. I have a small fluorescent digital clock I got from a scrapped car ages ago. It's got nowhere really for it to fit, so I'm going to think of some sort of attractive way for it to be glued on the dash somewhere.
I've had a go at making a subwoofer out of PVC pipe. My guesswork wasn't lucky and it was abandoned. But I have made several great subs from wooden boxes with or without backs to them. - I mean boxes which wouldn't be able to fit in my Hijet. This Hijet is nothing like a car as far as the sound is concerned. It sure is a noisy vehicle. There are two ways to get a better sound methinks. One is to soundproof the cab and the other is to use more watts with better speakers and a graphic equalizer - or both. I've got enough watts now, but now I've stumbled on the next biggest problem which is resonance. - I'm planning on trying that rubberised-undercoat once I find out what it is. - I expect it is messy to work with?
I figured out what 'undercoat' is. I wasn't thinking laterally and I was of the mind it was the paint which you put on before the top coat. So I was thinking 'oh! So there's an undercoat which is rubbery.' So it's under-coat - not undercoat. Did I pay attention to the way it was written here? I don't think so. Well I bought a couple of cans and I'm going to find out how it's used to best effect and I might have a go at putting some on either tonight under a spot-light or tomorrow. I did a test spray on a bit of concrete-block wall and noticed it runs if applied too thickly. So I suppose it should be used by spraying several coats. I hope it helps.
I looked about and tried to find some sagely advice about applying that undercoat. Unfortunately there wasn't much. Basically the best advice I got was to thoroughly clean the area to be sprayed, point, then shoot. Several coats? How long does it take to be dry enough to apply an additional coat? How long before the surface can withstand a shoe? My Hijet came with the most rudimentary carpeting available - just two rubber mats. - And I'm planning on spraying all of the floor. So can I use the truck without covering the undercoat with carpeting? ... I'd think a carpet of some kind would be needed over undercoating, and it would certainly look better and also contribute to the soundproofing and heat insulation. But would the carpeting need to be done right after the undercoating? Carpeting:- I suppose whatever carpet I use would be best glued permanently to the floor? So the way to do it would be to cover the undercoating with adhesive in strategic places and then plonk a piece of carpet down in the middle of each side, then slowly press it down and trim with a box-cutter as I go? So the way it should be done is for me to maybe get one more can of undercoat - to make it three cans. Then take the door panels off, take the seats out, then clean the surfaces. Then spray one coat and then hopefully the parts which were done first are ready for their second coat. Then one more coat for luck. When that's dried enough I should then stick some 'fitted' carpet to all the metal surfaces. The other undercoating, which is under the fenders means jacking the truck up a bit, then removing the plastic covers, then the same three coats of undercoat. The back wall means a bit of masking is necessary. But basically it's the same deal - with three coats of undercoat and carpet glued on top of that. I think I'd like to do the back wall on the outside as well with undercoat. How about the roof? As far as I can tell, the roof just has a loosely fitting wafer of cushioning/soundproofing. So I could take that out, spray the roof with a few coats of undercoat and then affix carpeting up there as well.
The rubberized rockerguard/undercoat isn't meant to be walked on directly...generally it works best in wheelwells door skins and under carpets or as an undercoating. The wrecking yards are full of excellent carpeting with sound deadening pads built into the backing..(Mercedes Bmw) some have nearly untouched carpets in the trunk or hatch and it's generally large enough to use anywhere on your mini. And you are correct..several light layers keeps it from running...I suspect the biggest problem for sound reduction is in the doors..
I have installed fatmat in two GTI's, from the firewall to the trunk lid. It quieted down motor, tire, and exhaust noises.
I'm too knackered to say just how much improvement (if any) has been made to the sound quality/road noise. I was up all night fiddling with some carpet trying to make it fit. So it fits - well mostly - well it's a truck anyway.:sly: Must get longer screws for the door speakers. The long 'stroke' domestic speakers got put in with a spacer made from 'concrete board,' and I need longer and thicker screws. The new door speakers replaced dual cone ones so I ought to put a couple of tweeters somewhere. When I get round to looking at what I've done after some sleep I'll see where I can mount a couple of tweeters. At least the cab is better insulated. I put a square of carpet under the driver's seat, but the passenger seat isn't meant to come apart. Two cans of undercoat is about a third or a quarter of what I should be using. I went to get some more u/coat but the shop had run out - They'll get some more next week. This is one of the perks of living on a small island. ... I mean not being able to get what you want. So with about one coat on most of the floor is as far as I got. I didn't use adhesive on the carpet, rather I want to be able to remove it. I'll have to tape something together so the carpet covers the wheel arches in front of the seats - I cut that area in several dart shapes and there's space between. Well I'll figure something out. What was I thinking when I imagined there were plastic wheel covers for the fender above the tyre? Of course there aren't any.op: - And the place where I bought it had done a coat or two of undercoating anyway everywhere underneath including above the tyres. At seven in the morning when I had put it all back together and switched on the stereo for the first time I thought it was broken. Eventually I remembered I hadn't connected the rear speakers because I was waiting until I could play something on the stereo to tell be which side was left and which was right. ... But I'm going to have to do the back wall, and maybe the roof as well. At least those areas are pretty straight-forward to cut a piece of carpet for. And I didn't have enough u/coat to do the driver's door. ...
While I had the plastic console under the stereo out I noticed two control boxes. One for electronic fuel injection and the other for the airbag. Shows how much I know of what I bought because I had always believed it was a carb job. - I'd seen Hijets before, and I thought the ones with EFI were only the ones with the lettering indicating this on the back of the tray. - Ah well! Maybe I didn't really want to fiddle with the carb settings anyway.
I think I've probably got the speakers sorted out. I ended up installing thirteen speakers in the end. - Four sets of woofer/mid-range/tweeters & the subwoofer makes for lucky thirteen. The front mid-range and tweeters are in the corners of the dash facing upwards so the high tones are reflected back by the windscreen. I didn't get round to the rest of the carpeting. I still have to do the back wall. But I bought some felt underlay which I plan to cut in strips and put in the recessed parts of the back wall. Then cover it with a sheet of 2mm thick plastic sheet, and on top of that I'll stick some carpet. Maybe I'll finish that job tomorrow? I had a look at the head-lining and the roof and decided it really needs some bracing to keep it from sounding like a drum. I didn't take the fibre mat in the roof out, but I moved it about to see how it comes off. And please correct me if I'm wrong, but I think you first slide the mat forwards as far as it'll go and then pull it out from the rear. I thought it would be a little tricky to do it so the front portion isn't mangled, but maybe it can be done neatly if the sheet is slid out with the assistance of a pronged-something levering it back from the front - where it is crammed. And the last job concerning the soundproofing effort is finishing the carpet on the floor. I have to fashion a piece to go around the door arches. It's not impossible if I take it slowly. Next job? Hmmm! I want a light in the back for the tray and I want a cigar-lighter. oh! And there's the clock! ... Better finish this job before I go on to the next one! - And my wife wants me to put a stereo in her car ASAP. ... Then there's the speedo cable to go in her 50cc Cub. - And the carb balancing to do on my ancient Katana. Never ends!
... Done the sound insulation (and heat insulation as well I suppose) on the back wall. I don't usually like leaving a job half-done, so with the fear of having to come back to a job I have to push myself a bit to get started. But once I've started I just plod on until it's done. I cut the 2mm mat to approximately the right height, and cut the rectangle out where the subwoofer sits and fixed it from the bottom up with double-sided tape. I could still do the carpet (on the back wall), but I wonder if it really needs it? It can't be seen easily and the seat backs are pretty sound-absorbing anyway. - And it's just a truck - For Gs. Now there's only one place left where insulation could make a difference in ride quality based on sound and heat insulation - and that's the roof! If I tap it, it sounds like a drum all right! A tinny sort of drum with no redeeming characteristics I can think of except it keeps the rain out. Before I fell asleep I was thinking of the best (quickest) way to make the roof more solid. No doubt in my mind that Astro-turf glued onto the roof would be good. It'd quieten the sound of the rain as well as deaden the sounds and the knockings. - But I aired the thought with my wife who convinced me of what I already suspected, which is that using Astro-turf is just too wierd. - So if I decide to go the whole hogg then the roof lining is going to have to come down. At least I think so. I could brace the lining to the roof with a spar or three. Another wild idea is to wedge some rubber matting between the lining and the roof by pushing the rubber through the 1cm opening which is possible by pushing the headlining as far forward as it'll go. I'll be glad when I've finished the stereo. - But I think it is likely the most finnicky job I have on my 'to-do' list with the truck.
Or how about drilling small holes strategically in the headlining and injecting adhesive, then pressing the headliner to the roof until it is set? Can't get much easier than that! Or I could use some spray-adhesive if I can manage to pry it down far enough to get the business-end of the can up there facing enough of the headlining and/or the roof.
The headlining isn't fibre. It's got some very thin cloth which looks fibrous but it's really just a plastic sheet made from a sort-of honeycomb pattern - most likely for strength and weight reasons. It wasn't hard to remove. First push the liner as far forwards as it'll go and then pull down the back end so you can slide it downwards some. Then lever it back from the front with a broad blade of some kind. Once the front is cleared of the slot between the frame and the roof you have to somehow bend it in the middle and then it virtually drops out. Putting it back in isn't difficult either. There are two 'wings' on the L & R sides of the lining. Somehow bend it in the middle and put those two bits in between the frame and the roof, then press the lining back on all sides with the same broad-bladed tool you used to take it off with. I needed to push the lining as far forwards as I could again. Then once the back's lined-up just lever the sheet backwards until it is supported on all the edges. I haven't driven far in it since I tried to insulate the roof. But I wonder if I haven't now eliminated the worst source of 'noise.' I put 2mm plastic sheet/mat on just about all of the non-edge area of the roof using contact adhesive. Then on the headliner I put lint/felt underlay on all but the edges with same contact adhesive. Before when the top was tapped it sounded like a demented cymbal. Now it goes 'thud!' So the job is done - unless I want to make the floor carpet a bit neater.
Photos. Hmmm! Well I've got all the ingredients now. - A blog, a homepage, a computer and a camera. S'cuse me for being so slow about it. But it's just the Japanese language menus which drive me bonkers. - ie - I haven't managed to get it all together quite yet. I've only had the homepage/blog for a few days and my wife has been busy getting it going - but I W.I.L.L. get the camera sorted out ASAP. Give me a week max. Now the reason I haven't done the camera set-up and sent or linked snaps out thus far is because I haven't tried very hard. I put the disk for the camera into the comp and it seemed to digest it. But when I clicked the new logo I get a message in Japanese telling me my camera isn't connected. I was expecting to find some sort of directory saying things like:- 'Your uploaded photos = 0' And I was expecting to find things like 'how to send photo by email, how to re-size etc etc ... .' - So it isn't going to talk to me until I introduce it to the camera via either the memory card or the wired connection. Fair enough. I just have to get my wife to hold my hand through the instructions and/or make the effort and do it myself. So as I understand it, it is possible to upload pics to places like "Photo bucket" - and then link from there? Or the way I'd like to do it is to link to somewhere on my homepage or my blog. Sorry if this is all so simple for you. Once I get going I think I'll actually become annoying with my pics spamming threads everywhere.
I figured out how to upload the pics from my camera and file them. And I also learnt how to send a pic as an attachment to an email. ... It won't be long now.
Is this the great moment in time when I make my first ever successful pic on the internet? Let's see... . I wonder how big the pic (if any) is? Well here goes:-
The eight mounting bolts for subwoofer through back wall. View of the inside of the cab. My modest (old) stereo slotted in fine - Also the old digital clock I glued in. The controller for the subwoofer is glued to the trough above the stereo. One set of rear speakers. Two small tweeters - the one on the left is piezo and the larger one is moving coil. Above the seat there is a black box. That's a speaker from a flat-screen TV. They are rated at 5W, and the sound isn't bad at all considering the size (about 1 X 4 X 8cm each). Simple connections throughout. I like making connectors. Subwoofer seen from the passenger door side. It's a snug fit. There's a rubbery plastic 2mm sheet and some felt/lint undercarpeting on the wall under the window. Passenger door speaker. It's a domestic-stereo speaker and I used the delicate mahogany disc (painted concrete-board-orange) to allow the magnet to clear the window. The speaker wire is run through some cable-tidy stuff and is just wedged between the frame and the dash console. The brown stuff on and around the hinges is purportedly antirust grease. Ugly stuff, isn't it! And lastly in this post is a shot of the front tweeters. The sound is rather good. Good job I like naked stuff. Nice tweeters actually. - I put bypass caps of too high a capacitance so when it stops raining I'll be out there with the extension cable and my soldering iron to change them. Next I might need to learn to down-size the pics. Jap Windows is a nightmare for lazy gaijin like me I can tell you.
wow you jammed a lot of speakers in there. and a double din head unit...what mf caps did you try...I have a bunch laying around and was gonna put some inline on my fronts..wasn't sure which size (mfs) to use tho. Is the red paint in the bed some kind of Japanese market bedliner paint? love the pics
