RX400h door speaker surround failed

[Parrot of Doom]

Hi all, the speaker surround on my driver's door has failed.  Pics attached.  Obviously I'm not going to buy a brand new one for an 18-year-old car, has anyone had success with a foam repair kit?  Or does anyone know what the driver is (Mark Levinson have helpfully put their own label onto what is very likely made by someone else).

[Herbie]

Measure the impedance (in this case resistance will do) and just buy a generic one that fits the physical space.

[Tomtit]

I bought a repair kit for the subwoofer on the LS430. Bought from eBay and it has been fine for over a year.

[Parrot of Doom]

Which seller did you use?  The only likely candidate I've found so far is a company called Simply Speakers, based in the US.

[Tomtit]

I have just checked my invoices. It was bought over 3 years ago. The eBay seller was speaker-repairs, based in Cheshunt, Herts. The kit came with instructions and was straightforward to use.

[GSLV6]

I've repaired quite a few.  It's not difficult but it does need care to avoid creasing the cone.   Measuring DCR of voicecoil won't provide enough for a close match.  It's the Thiele-Small parameters that matter so finding one with similar "Vas", "Fs" (free air resonance in Hz), power handling and sensitivity are all really needed to get a close match.  If there are any clues to what driver it is, I may be able to help as I'm a loudspeaker engineer.

However, these do crop up on eBay (some on there presently) so easier to replace like for like with one that's in good used condition from there (about £50 or £60 each)

[GSLV6]

https://www.ebay.co.uk/itm/234636662146?campid=5338627314&mkevt=1&mkcid=1&toolid=10050&customid=Cj0KCQiAxbefBhDfARIsAL4XLRpR5CsOotY0PvH_htj5Dgcd22UonLIUzttt3vSH_oQ4NUzk2M0aZjAaApJeEALw_wcB&mkrid=710-53481-19255-0&customid=Cj0KCQiAxbefBhDfARIsAL4XLRpR5CsOotY0PvH_htj5Dgcd22UonLIUzttt3vSH_oQ4NUzk2M0aZjAaApJeEALw_wcB&gclid=Cj0KCQiAxbefBhDfARIsAL4XLRpR5CsOotY0PvH_htj5Dgcd22UonLIUzttt3vSH_oQ4NUzk2M0aZjAaApJeEALw_wcB

[Herbie]

6 hours ago, GSLV6 said:

I may be able to help as I'm a loudspeaker engineer.

Ooh, ooh, I need you Paul

Sorry to hijack the thread folks but a quick question if I may...

I bought one of these little stereo amplifiers and it arrived yesterday. I listen to a lot of varied stuff but my main love is classic rock, with bands such as LED Zeppelin, Rolling Stones, AC/DC, The Who, Deep Purple and so on, along with a lot of Blues from Joe Bonamassa, B.B. King, Elles Bailey etc.

I'm no audiophile by any means and the manual says the amp will drive any speakers from 3 to 8Ω so my question is, is there a "best" impedance to go with?

I have a couple of KEF HTS-2001 'Egg' speakers like the ones below and the label states 10-100W 8Ω. Will these work and be good, bad or indifferent? Or should I get a couple of speakers with a different impedance?

TIA

[GSLV6]

Just PM me Herbie for detailed advice if needed.  Basically, most amps are designed as voltage sources which swing the current to meet the demands of loudspeaker loads.  Their stated output is usually in Watts RMS which is a sort of maximum mean power they are designed to operate at.  Most solid state amps (Class A/B and Class D) are capable of happily driving loads with nominal impedances between 4 and 8 Ohms with no problems.

However, to ensure the best match it is a good rule of thumb to cater for transient peaks in current demand at lower impedances so I would always advise choosing an amp with double the minimum stated power needs of the speaker load to allow for transient peak power demands in the lower frequencies.

The stated speaker impedance uis usually described as the nominal speaker impedance, so an 8 Ohm nominal impedance means any amp is suitable that can drive an 8 Ohm load.  A speaker rated at 8 Ohms can have a minimum impedance in the bass registers of more like 6 ohms, ditto a 4 ohm speaker can have a minimum impedance of 2.5 to 3.5 ohms in the lower frequencies so an amp capable of delivering power into a 4 ohm load is recommended.

However, when you look at speaker ratings, they also include a sensitivity rating in dB/1w/1m (or watts for 2.83V/1m).  If you take a speaker capable of outputting 90dB/1m/1w into 8 ohms and one which outputs the same into a 4 Ohm load, then using 4 ohm taps on some amps (mostly these days it's just valve amps with optional impedance load outputs) then using the 4 ohm tapping results in the 8 ohm speaker still working fine but with around 60% of the available power on tap, lower distortion and better damping factor so it will sound quieter for the same volume setting.  Conversely a 4 ohm speaker driven from 8 ohm taps or amp designed for an 8 ohm load will work fine but if you drive it too hard the amp could run out of power and into clipping as the power needed to give the same output as 8 ohm speakers is double.

In your case you have a little Chinese op-amp amplifier with tube buffers in the output stage (ie not a true valve amp).  It will work but with those speakers which are nominal 8 ohm loads, you'll see half the power available from that amp, or perhaps a little less so in reality it can only supply enough current to drive them with a maximum output of 50 wpc and will likely clip if you overdrive it.

If you don't need the Bluetooth connectivity you'd be better advised using a better designed more conventional amp which can output 100wpc into an 8 ohm load.   Sorry for the thread drift!

 

[Herbie]

Wow, thanks for such a detailed reply Paul, much appreciated.

And yes, sorry for the off topic post folks.

[Las Palmas]

The speaker you have is a standard size 6x9" which most companies make. Get one from a major brand. They cost little and trying to fix suspension on a loudspeaker is not something to do.

https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=loudspeaker+6x9+woofer&_sacat=0&LH_TitleDesc=0&_odkw=loudspeaker+6x9&_osacat=0

If you want to fix the one you have:

https://www.ebay.co.uk/itm/122775712280?hash=item1c9600b218:g:uD8AAOSws6ZZ8poA&amdata=enc%3AAQAHAAAAsDsC81rliaz8p3Le%2FRSI98SvH2y6iNBDS5Wj7ze9Ot%2F4E0G%2BGcppTHSQYMYpVXMZDG%2BFppj2jrQZ0HEbSk9%2Bbt%2BlcQ2jmdCk0zASeZwpXT81q5KuRJwWAnp10%2BLodnGuOl%2FR%2BKNBRDAMvQbd8KqzvGYu7mWyXmNldYTC2DE6p4LPVsGEw4NG3Sw3XRo99zfSRqJ2AUPXGonOqNiIw6cFFW8lEHIRukA4FUbWxcimMKWF|tkp%3ABk9SR_7rj_7LYQ

[GSLV6]

Suspension is the part that joins the voicecoil/cone assembly to the motor assembly and can be replaced if parts are available although it's not one for a diy enthusiast as it can be very tricky. The surround (which I think you mean) is the foam or rubber surround to the cone and these are routinely replaced for most hifi speakers where needed.  Not all drive units will sound the same even if the same size (but from a different manufacturer...ie they are NOT the same designs) but replacing with a good used like for like speaker drive unit is probably the most practical proposition.

[Parrot of Doom]

Thanks all, I eventually bought a kit from Simply Speakers on eBay.  Based in the US so it cost about 50 or 60 quid for a pair, and some glue.

The surround is about 2cm too long so I cut it and overlapped.  I also trimmed about a millimetre from the edge, all the way around.  The glue provided is decent, it gets very tacky within a couple of minutes so it's fairly simple to fix the surround in place before it dries completely.

It's not exactly pretty to look at but neither is the cone tbh, it's just a car door speaker so doesn't need to be perfect.  Funnily enough it mostly does the low end, so driving around without it for a few miles didn't really sound that bad.

I do actually own a decent hifi (Roksan, Naim, Musical Fidelity, Quad etc) so am what you might call an audiophile, but honestly, when you're doing 60mph down the motorway, who cares if one speaker sounds slightly different to the other...