Fitting speakers to the cubbies for those with basic hi-fi...

[Magicarcher]

Here it is (blue) compared to the tangband (green) in a 5L cabinet where the tangband imho still performs better and can produce more volume due to its larger xmax (12mm vs 9mm):

Have you by any chance calculated the volume of the rear cubby areas. I tried to calculate it using a series of calculated cube and trapezoid measurements, but it is an absolute pig, the area is so irregular. I read a BMW technical document somewhere that said it was 10-11L but there is no way it is that big. I calculated it is somewhere between 5L and 6L

[Anmarube]

I have Morels in the rear cubbies and in the footwells. 10" sub in the boot. Fantastic when roof up but disappointing bass when down so have to find a way to get bass in the cabin when down. Think the Morels in the cubbies are going to be replaced with some long throw drivers.

[ph001]

I think it about 4l. Defo less than a petrol can which is 5l. Good shout on the Reckhorns, amazing value. Have a Reckhorn amp powering my 10hz transducer bolted to my settee in my AV room. Nice piece of kit.

[GuidoK]

With you 100%, have you considered Reckhorn D165, half the price of the Tangband and very well made German loudspeakers.

I didnt consider/know that one (I've been out of the diy scene probably as long as I've been in it....), but it simulates very nice:


Not quite as good as the tangband (which has the upper hand to the -6db point) in a 5L box (but the difference is minimal), and it doesnt have the massive 12mm xmax from the tangband, which I've not seen in this class before thus quite unique (so the tangband will be able to produce more bass if amplifier power is sufficient), but in smaller cabinets (3L) the reckhorn does better because the Qbox is lower. And indeed very very cheap for that speaker. The tangband is already very cheap (€60) compared to say a JL audio jl audio 6w3v3 (€170) or 6,5"peerless SLS (€90), but €30 for such a nice minisub is crazy.

Have you by any chance calculated the volume of the rear cubby areas. I tried to calculate it using a series of calculated cube and trapezoid measurements, but it is an absolute pig, the area is so irregular. I read a BMW technical document somewhere that said it was 10-11L but there is no way it is that big. I calculated it is somewhere between 5L and 6L

No I just made a guess. Its certainly not 10-11L (thats the size of a bucket!), and dont forget that the volume of the sub itself also has to be subtracted (1-2L)
TBH, if one could get the original carver units for cheap, those would also be an option. They're quite well made. An odd impedance, but you could wire them in parallel and use a 2 channel amp in bridge mode to get the most power out of it (amps usually work to 4ohm in bridge and the nominal impedance of 2 carvers in parallel is 5ohm, so a safe setup. I think the factory hifi pro DSP setup is the same.

I think the biggest question which hasnt been answered yet is: will a normal 6,5" sub fit, or does it have to be smaller.
If it has to be smaller, the availability of long throw chassis decreases significantly.

[ph001]

I suppose we ought to consider the fact that the OEM installation IS ported. I think it's done through the oval cutout in the top of the enclosure, You have little chance of finding the thiele small parameters for the oem driver I guess but maybe a fully sealed enclosure is not the way to go.

Would be difficult to model though I bet as the port is effectively cutoff from the front of the driver by the fascia trim (well not completely isolated as there are a few vents and gaps around the cd changer that lead back around to the front), but it's certainly a complex path. It's kind of halfway between using the boot as the box volume (almost infinite baffle) with a bit of leakage thrown in!

[MrPT]

If you go ported, the reflex system will colour the sound a bit and you’ll need to think more about the amplitude of harmonics compared to a sealed system; especially if you want to set your crossover frequency quite high (for enhanced mid bass). The results can be quite unpleasant in difficult spaces, which is why room correction + cheap speakers is often better value for money than expensive speakers and no ability to tame resonant modes etc.

I wonder whether a passive radiator setup might be best, using the cubby hole space to link an active and a passive long throw driver? Again, not a clue whether this is ever done in car audio circles, but in home audio you can build very high performance subwoofers economically with pairs of units from the likes of Peerless etc. Assume you don’t want to bore a mini Channel Tunnel through your CD changer though.

[ph001]

Well I've just pulled the plug on a couple of those Reckhorn 6.5" subs and also bought two of the oem rubber grommets that form the port on the Carver system. I'll have a play about using the Morel Ultra 602 and then the Reckhorns. I'll try fully sealed and then ported for both drivers. To make it a little more scientific I'll use a wideband microphone and laptop with REW (room equalization wizard) on a 20Hz - 1Khz sine sweep to look at the actual freq response in the driver seat. I suppose I should do a run with roof up and lowered too.

[ph001]

At the very bottom end of the price range I did find these... https://www.thompsonsltd.co.uk/brands-l ... ngle).html

£12 for a 6.5" subwoofer!!! I have heard of Lanzar so it's not like they are some unknown Chinese brand. The Thiele small parameters look very strange though, so much so that it wouldn't even simulate... 6.8cuft for the VAS is 192.55l !!

Reckhorn D-165:
FS: 28 Hz, Qms: 5,69, Qes: 0,32, Qts: 0,30, Vas: = 17l Mms = 43 g, BL = 9,38, Sd = 132 qcm


Lanzar MAXP64
Fs: 80Hz, Qms: 4.05, Qes: 1.3, Qts: 1.2, Vas: 6.8Cuft (192.5l)

[IAmOrion]

At the very bottom end of the price range I did find these... https://www.thompsonsltd.co.uk/brands-l ... ngle).html

£12 for a 6.5" subwoofer!!! I have heard of Lanzar so it's not like they are some unknown Chinese brand. The Thiele small parameters look very strange though, so much so that it wouldn't even simulate... 6.8cuft for the VAS is 192.55l !!

For £13 they gotta be worth a punt! I might give them a go myself.

I just purchased a set of rear cubby speakers from a forum member (Simon) (viewtopic.php?f=7&t=105049). I have a Pioneer head unit, with a Kenwood KSC-SW11 attached via the subwoofer out RCA. I just split the RCA, and added a small £55 Pioneer amp in the boot, to drive the new speakers. Sounds really nice - they're the default speakers not subs although I'm contemplating making them subs.... that being said, the main reason I wanted these was because the Kenwood Sub is actually enough for me, but when on motorway I struggled to hear the music - only heard the thumping from the sub hence why I wanted these to increase my unfiltered volumes.

[Magicarcher]

.. I think it's done through the oval cutout in the top of the enclosure..

Thanks for that, I am in the process of blanking off all holes in the steel cubby enclosure and discovered the 60mm x 80mm (approx) cut-out at the top which I nearly missed. Now at least I know what it is for.

[Magicarcher]

No I just made a guess. Its certainly not 10-11L (thats the size of a bucket!), and dont forget that the volume of the sub itself also has to be subtracted (1-2L)

I definitely remember reading it in BMW technical document on their HiFi carver system. I am wondering if the value is for the pair of cubbies. Good call on subtracting the volume of the speakers themselves. For modelling the output I use Android App Speaker Box Lite, though annoyingly the latest download appears to need me to register before using it in anger, never used to be the case.

[GuidoK]

I suppose we ought to consider the fact that the OEM installation IS ported. I think it's done through the oval cutout in the top of the enclosure, You have little chance of finding the thiele small parameters for the oem driver I guess but maybe a fully sealed enclosure is not the way to go.

I dont know if the carver is ported. I dont think so.
There is no real port, thats for sure.
I've had them out but I dont remember a distict gap also.

The drivers you've selected are definately not suited for ported operation, you'll see what I'm talking about once you've simulated that. There are serious physical limitations for that. Closed box is definately the way to go, follow the simulations.

At the very bottom end of the price range I did find these... https://www.thompsonsltd.co.uk/brands-l ... ngle).html

£12 for a 6.5" subwoofer!!! I have heard of Lanzar so it's not like they are some unknown Chinese brand. The Thiele small parameters look very strange though, so much so that it wouldn't even simulate... 6.8cuft for the VAS is 192.55l !!

Lanzar MAXP64
Fs: 80Hz, Qms: 4.05, Qes: 1.3, Qts: 1.2, Vas: 6.8Cuft (192.5l)

Anything with that Qts you can leave on the shelf for this application.
Its not suited for either BR or closed box. Useless driver imo, only suitable for 'open air' suspension, like in rear shelf applications.
(and Lanzar is a brand not to be taken seriously to begin with)

[ph001]

I dont know if the carver is ported. I dont think so.
There is no real port, thats for sure.
I've had them out but I dont remember a distict gap also.

Hmmm, I know what you mean in that it isn't a tuned port in terms of length etc, but I'm fairly certain the rectangle on the topside of the enclosure is open via the grommet (item 10). Maybe they just use the grommet to reduce the wind noise around the metal edge of the hole?

rear speakers.jpg (40.34 KiB) Viewed 1415 times

[IAmOrion]

Hmmm, I know what you mean in that it isn't a tuned port in terms of length etc, but I'm fairly certain the rectangle on the topside of the enclosure is open via the grommet (item 10). Maybe they just use the grommet to reduce the wind noise around the metal edge of the hole?
rear speakers.jpg

Is the grommet perhaps for the speaker cables? I mean, in mine (which I had apart the other day) I have (had) additional speaker connections but no speakers... The connections to speakers (1) in the pic go up behind the carpet in the boot and to the rear of the speaker. Wouldn't it make sense that the wiring for speaker (4) follows the same path, but then through the grommet to the rear of that speaker?

Not sure I made any sense there but I know what I mean lol

[GuidoK]

Hmmm, I know what you mean in that it isn't a tuned port in terms of length etc, but I'm fairly certain the rectangle on the topside of the enclosure is open via the grommet (item 10). Maybe they just use the grommet to reduce the wind noise around the metal edge of the hole?
rear speakers.jpg

If the grommet sits in item 9: item 9 is a soft piece. I dont think thats the box, but rather the dampening material? I'm not sure whats behind that.
If the boot is behind that, its an open air setup and not a box of any kind.

I have the carver DSP option, and I had the speakers out (to look at the speakers) but I didnt really look inside the box past the dampening material to see if there is an actual box behind it
But I suspect that is the same for every car as it would probably be the chassis, so you can look for yourself behind the cubbyholes.

To go for a ported setup in this situation you get those odd physical extremities that you need a 3ft long port and such things to get it decently tuned on the box volume and speaker parameters....
I made a quick simulation, for the Reckhorn D-165 to go ported, you need a 89cm long port with a 2" diameter to get it tuned, and then it simulates beautifully, goes really deep (-3dB at 47Hz). But where do you leave that 3' long pipe? With a bigger diameter pipe you only need more lenght and if you go smaller, the air speed velocity in the pipe gets really high so you hear pumping air sounds..