Octavia II Poor Sounding Stereo Fix

[Genoa1893]

The greencaps are polarised? wasn't marked as such.:confused:

Thanks mate.

You're welcome ,

no film caps are not polarized. Standard electrolytics are; not polarised electrolytics are used in louspeakers crossovers to cut... costs

Ciao!

[Genoa1893]

I bought the kit for the estate from here.

Noisekiller UK - Sound Proofing Cars

I placed the various pads under front & rear carpets, bonnet, boot floor and spare wheel bay and rear side panels & wheel arches. I never got round to placing the specific pads inside the doors. I was waiting for another reason to take the door cards off.

Thank you Jules,

so it is basically a set of damping sheets, isn't it? What is the cost (I couldn't find them on noisekiller site)?

TIA

[Jules59]

Thank you Jules,

so it is basically a set of damping sheets, isn't it? What is the cost (I couldn't find them on noisekiller site)?

TIA

£195 inc delivery for 27 pre-cut pieces of damping material - some self adhesive.

[Penguin]

£195 inc delivery for 27 pre-cut pieces of damping material - some self adhesive.

Does this kit actually make a lot of difference to tyre / road noise . I was tempted but thought £195 was quite a lot if it didn't make much difference?

[Genoa1893]

Honestly, I dare to say it's a lot anyway for my thin wallet...

[Jules59]

Does this kit actually make a lot of difference to tyre / road noise . I was tempted but thought £195 was quite a lot if it didn't make much difference?

It certainly cut down the background noise but the tyres can still be very loud on some surfaces. Its still far from very quiet - not as quiet as my old discovery TD5 and nowhere near as quiet as our current freelander 2.

I thought about acquiring the stuff myself and doing it all DIY but all the sound insulation materials are very expensive retail and i dont know anyone in the trade. So for me it wasnt a bad deal.

[magic62]

Did my twick last night. Am really surprised what this tweak does.

A lot more soundcomfort in the car. Thanks again, was worth the effort (and the effort is a little more than the cost )

Bought Visaton caps in 3.3uF for just a bit more than 1 euro each.

[magic62]

@Jules59, I used your photo in the german board, hope you dont mind.

[Jules59]

@Jules59, I used your photo in the german board, hope you dont mind.

I dont mind at all - except they are the wrong capacitors in my pics. But the correct ones (as explained in this thread) are wired similarly.

[magic62]

Wrote some words to the picture and mentioned that the caps werent the right ones.

Thanks, I am spreading the news

[Stott]

Shortly, better quality is needed for higher specs. So a cap rated for 100v(ac) is typically better than a 50v(ac) rated one.

Untrue, using the correct part for the job is important for quality, typically in electronics using a part that is too highly rated reduces accuracy in the intended operating range. No need.

[chavdarlk]

Untrue, using the correct part for the job is important for quality, typically in electronics using a part that is too highly rated reduces accuracy in the intended operating range. No need.

Your statement is untrue... Overrating in the electronics leads only to oversizing, nothing bad .

Particularly, with the capacitor voltage - high nominal voltage -> high linearity. (especially for electrolytics).

[Genoa1893]

Your statement is untrue... Overrating in the electronics leads only to oversizing, nothing bad .

Particularly, with the capacitor voltage - high nominal voltage -> high linearity. (especially for electrolytics).

@Chavdar, thanks for your fast and smart answer

Untrue, using the correct part for the job is important for quality, typically in electronics using a part that is too highly rated reduces accuracy in the intended operating range. No need.

@Stott: I'd suggest you to read something on caps - there are tons of links on the web - then also wonder that on the other side may read some electronics engineers, eventually hifi/high-end addicted.

@all: A nice link on the characteristics of sound of different caps used in loudspeakers crossovers (what is the thread about) is Humble Homemade Hifi. Most of them will be simply too much for a car application, but I found it an interesting reading nonetheless.

Have a nice day,

[Stott]

From the link:

For optimum results all capacitors in a series filters should be of the same high quality, even the ones in correction and Zobel networks! Also the higher the quality of the hi-fi-system the more obvious the difference between the various capacitors will be. A higher rating doesn’t always mean “better”; it depends on the implementation which capacitor is “the best” for your situation. Just replacing everything with the capacitor with the highest rating isn’t always the optimal solution, try using different caps in different places throughout the crossover; it’s just like cooking! A bit of pepper here, a pinch a salt there, etc. and try to get your favourite “blend” of sound that way, and don’t forget the Vishay Roederstein MKP1837. To be continued!

Tony Gee - The Netherlands

[Genoa1893]

Let's make this whole thing short: try a bunch of different caps with different ratings then get back to us and enlighten us with your results (of course I'm speaking of high quality loudspeaker applications where bipolar elco are not even considered).

Easy sport to cut portions of a long history and giving it your meaning. From the link there are other info: 1) even a cheap MKP is better than any bipolar elco. 2) The majority of these caps are high voltage rated: guess why? BTW There are 2 63VDC caps with humble performance, albeit 100VDC Duelund is outstanding (due to particular materials used and construction, I guess).

Back to topic, voltage rating specs of the OEM Skoda caps are obviously tailored to contain costs, and it seems they didn't even pay too much attention towards integration between tw and wf, as Penguin demonstrated, and this is the last things I wrote for Stott, only, of course.

Edited 31 March, 2009 by Genoa1893

[moronica]

Dear Genoa1893, I don't usually comment on peoples opinions, however, there are a few inaccuracies that need clearing up to help the many people who have read these posts intending to actually carrying out the capacitor mod.

The capacitors for a cross over should be non-polarised, to enable them to filter ac and not because they are cheaper. If you fit a polarised capacitor the wrong way around you run the risk of it failing or at worse gassing, exploding or going on fire.

The original Skoda capacitors were not unfit for the purpose because of their cheapness or lower voltage capacity; they simply had the wrong value of capacitance.

It is an absolute waste of time and money to over specify electrical components in any circuit without a valid reason, more expense does not automatically equate to an improved sound. You are only as good as your weakest link. I totally agree with Stott

Higher voltage capacitors usually mean a larger size to allow for the additional insulation required to meet the higher voltage; Motor Capacitors are far too large for the intended application. Ensure it is fit for the purpose, its no good if it fills your boot.

Before slagging off products (cheap crap) or wrongly specifying capacitors I would consider whether you are leaving yourself open to litigation, especially from Maplins or Skoda to name a few!

[chavdarlk]

Just have to specify the things

For given type of capacitor, the higher the voltage rating, the better the results.

Do not compare voltage ratings of different capacitor types!

Higher voltage -> higher linearity for given (small) signal amplitude

Higher voltage -> lower ESR (Equivalent Series Resistance)

Higher voltage -> lower inductance

Higher voltage -> higher maximum ripple current

Higher voltage -> longer capacitor life

...

Higher voltage -> bigger dimensions :thumbdwn:

Just consider one important thing - the capacitor and the tweeter forms a series RCL resonance circuit. In such configuration at resonance frequency you will get much higher voltage across the capacitor than the input voltage!

Interactive demonstration of RCL a.c. series circuit

[Genoa1893]

Dear Genoa1893, I don't usually comment on peoples opinions, however, there are a few inaccuracies that need clearing up to help the many people who have read these posts intending to actually carrying out the capacitor mod.

The capacitors for a cross over should be non-polarised, to enable them to filter ac and not because they are cheaper. If you fit a polarised capacitor the wrong way around you run the risk of it failing or at worse gassing, exploding or going on fire.

The original Skoda capacitors were not unfit for the purpose because of their cheapness or lower voltage capacity; they simply had the wrong value of capacitance.

It is an absolute waste of time and money to over specify electrical components in any circuit without a valid reason, more expense does not automatically equate to an improved sound. You are only as good as your weakest link. I totally agree with Stott

Higher voltage capacitors usually mean a larger size to allow for the additional insulation required to meet the higher voltage; Motor Capacitors are far too large for the intended application. Ensure it is fit for the purpose, its no good if it fills your boot.

Before slagging off products (cheap crap) or wrongly specifying capacitors I would consider whether you are leaving yourself open to litigation, especially from Maplins or Skoda to name a few!

Sincerely I have not enough time to answer in detail, or taking it personal as I seem you wish to but: MKP are not polarized, nor anyone ever said to mount electrolytics in speakers. Bipolar electrolytics are not known as good sounding regardless the xover implementation made in the Octy (as many times written the integration between tw and wf by Skoda seemed not too well cured). MKP at 250VAC have small sizes, and compatible with original cap position, small motor cap (2.2uF) have small sizes anyway. For my (and only my) ears a bipolar elco in a xover is crap, besides a MKP equivalent one costs only a couple bucks/each, not hundreds. Such components are available even from Maplin, or Farnell or whatever supplier you like. And last but not least I love my Skoda

EOF

[moronica]

"Higher voltage -> higher linearity for given (small) signal amplitude

Higher voltage -> lower ESR (Equivalent Series Resistance)

Higher voltage -> lower inductance

Higher voltage -> higher maximum ripple current

Higher voltage -> longer capacitor life

...

Higher voltage -> bigger dimensions"

Sorry Genoa it was not personal.

The point I was trying to make was that whilst you are able to continuously upgrade a component there are limits as to whether the improvements are noticeable within the intended application.

The tolerance will have a bearing on the sound as will the impedance, ESR and inductance; as to whether a higher or lower impedance, ESR or inductance value would improve the sound is down to trial and error, no doubt the existing components and speaker characteristics would also influence the sound. Higher maximum ripple current again should not matter for this application, albeit ripple is not a good thing.

The capacitors should in all fairness out last the life of the car because they are not working remotely close to their maximum design limits.

Previously the sound was very shrill on female vocalists especially on higher volume listening, very painful to my ears; people speaking on FM radio sounded different to how they usually sound, sometimes it was difficult to recognise who they were. At the time I thought that the OEM capacitors were letting too much Low/Mid frequency sound through to the tweeters, thus, disturbing their ability to deal with the high frequencies. After installed the Maplins - NP 3.3 uF 100v Part No. JA77J at £0.12 each, the sound is much more listenable; smoother and a lot less shrill, no need to lower the treble to avoid the pain; peoples voices now sound far more realistic.

Whilst the improvement realised is substantial, the components need bedding in and I am sure with a bit of experimentation, sound could improve further.

As posted on the 20/03/09 I am still interested if anyone has compared the sound difference between the NP 3.3 uF 100v Part No. JA77J and any other capacitors.

[Genoa1893]

And, at last, after too much talking here am I, too.

During the weekend I got the door handle bits and excluded the OEM bipolar elco by wiring a brand new visaton MKP 3.3uF. Even when just rewired I found I could raise the volume much more, sound is cleaner and effortless (given doors were opened, I also stuffed some batting inside the doors and placed some other under rear seats and under the boot, in the wheel well, too).

This morning I could listen to music better. High frequencies are already much more refined than with the bipolar elco (btw, listen, or better read something here: questions about bypass caps in Xover - Head-Fi: Covering Headphones, Earphones and Portable Audio). In a next step I might add a further MKP bypass, but let's go with a bit of break-in, before.

Aloha,

[Genoa1893]

You must bear with me, friends, but I have a horrible feeling... If the wire "feeding" the tweeter with + is the red/black one (assuming the "-" is the plain black one), we - and Skoda too - wired the tweeter BEFORE the cap and not vice versa! :eek:

Hadn't the time to test yet, please, tell me I'm getting older and older...:P

[chavdarlk]

The order of components is irrelevant.

[wardth]

I'm what you might term a dyed in the wool audiophile who has valve monoblock amps, a Gyrodek/ SME/ Koetsu front end and I spend quite frankly ridiculous amounts of money of cables, connectors, magic potions and witchcraft in the search of the perfect sound but once thing is for sure, I couldn't talk anywhere near the amount of cobblers you two have over the protracted length of this post!

I reckon the pair of you need to just lock yourselves in a padded room for a day until you tire of discussing the pros and cons of bloody capacitors!

Does the mod sound better? Yes / No?

If yes then great - a slightly overspecced cap will make sod all difference to a 10p tweeter.

Enough already!!

[wardth]

BTW, does anybody have the correct specs for the capacitor?

:rofl:

[Genoa1893]

Are you really sure? I agree that in an electrotechnical theoretically pure approach the resulting graph and equivalent function of transfer doesn't change a comma, but in all the schematics I've seen in years, the cap was wired to "+" connector, as electrons moves "towards" + pole...