Capacitor/resistor

[Vince]

Hi, I'm looking for some advice as well as the actual components.
I have a pair of Silver Iris tweeters that I wish to add to my existing speakers. I'm not changing my current speakers, merely adding the Iris's to see if it adds or subtracts, soundwise.
I want to simply add them by connecting with a positive and negative cable to each input from my speaker terminals. Basically the same if I was adding supertweeters and I want something to filter out the mid bass
Frequency's below 2.5khz. I just want something I can run inline on the connecting cables. The crossover of my speakers is 2.8kh, but I want to go a little lower.
Anyone got a good make of what I need or can tell me what I need.
Thanks in advance and stay healthy.
Vince

[Ali Tait]

8uF will get you to 2.5khz high pass.

I use Miflex on the tweeters in my Bastanis, I like them-

https://www.hificollective.co.uk/catalog/miflex-kpcu01h582j-8-2uf-600v-kpcu-copper-foil-capacitor.html

[Ali Tait]

Not cheap mind!

[walpurgis]

Not cheap mind!

Ouch!

[Ali Tait]

If they are too rich, this might help you decide-

http://www.humblehomemadehifi.com/Cap.html

Trouble is that large a value in a poly will not be cheap..

[Ali Tait]

8uF will get you to 2.5khz high pass.

I use Miflex on the tweeters in my Bastanis, I like them-

https://www.hificollective.co.uk/catalog/miflex-kpcu01h582j-8-2uf-600v-kpcu-copper-foil-capacitor.html

Sorry, forgot to say that value is assuming an 8ohm tweeter.

[walpurgis]

Sorry, forgot to say that value is assuming an 8ohm tweeter.

I seem to recall Goodmans using 8uF in a 3kHz filter. Not that it makes much odds at 6db/oct. Maybe they just wanted the roll-in late.

[Ali Tait]

It may well have been depending on the impedance of the driver, but as you say, not much odds at 6db/Oct.

[Mr.Ian]

what about cheap motor run polyprops to test the concept ? before going the whole hog ?

[Ali Tait]

Yep not a bad idea. The maths are the maths though, so if the OP is sure of the frequency and the tweeter is 8 ohm nominal, 8uf is correct.

[loosend]

U will need to check the phase if ur original crossover also to ensure u run the super tweeter correctly else all u will do is cancel things out - I’ve done that before
I use Mundorf Supreme Silver Gold in Oil 8uf, again pricey but great
The standard supremes also sound excellent

[Vince]

8uF will get you to 2.5khz high pass.

I use Miflex on the tweeters in my Bastanis, I like them-

https://www.hificollective.co.uk/catalog/miflex-kpcu01h582j-8-2uf-600v-kpcu-copper-foil-capacitor.html

Thanks for that Ali,
It's a lot more than I paid for both tweeters. I was thinking along the lines of maybe a tenner each, to see if I liked it or not.
Cheers

[Vince]

Thanks guys,
I'll see how it goes with something cheap first, but thankyou all for your help.
Much appreciated
Vince

[Ali Tait]

MCaps are cheap-

https://www.hificollective.co.uk/catalog/mkp630-82uf-630v-mcap-polypropylene-capacitor-p-8562.html

[Vince]

Sorry to ask, but I have make sure, I'll only need one per tweeter, I think, in the positive connection.
Cheers

[Ali Tait]

Yes one in series with the positive connection.

You also need to consider relative sensitivities, an L-Pad would be a good idea so you can match the tweeter level to the main driver.

[Firebottle]

Loads of cheap 8uF if you search.

https://www.ebay.co.uk/itm/1pcs-CDE-950-8uF-250V-ac-5-950CQW8J-Polypropylene-Axial-Film-Capacitor/153021533228?hash=item23a0cb4c2c:g:6bgAAMXQVT9SvV5 D

https://www.ebay.co.uk/itm/2X-AC-450V-8uF-Polypropylene-Film-Motor-Running-Capacitor-H7E3/333437558054?epid=1269152968&_trkparms=ispr%3D1&hash=item4da26d5d26:g:-J4AAOSw~hZd9Fry&enc=AQAEAAACYBPxNw%2BVj6nta7CKEs3N0qV4fO951yo7K76N OdsB4%2FMpsOcm%2FlUX9rsqpZ%2FOfWDz7FlLKtUD9nJO9pkM cU5YHcwr55JuuPaVg9XoxZfkwiHjumRIN6j7U%2BA5KnedFvj5 An1w5PDmk%2Fnk3tSiRHzdeChrEJzDcHZKJhsP%2BaYPzKHm2d jBAGxfo3HFL6fkILW870ho9BQMFamSubkxI2lf0t60Ybuahgd3 TbY7F9fLyHQIV6qIeAuocWwTTFavCYmQuvGKoK93pNTd38mvER x8pcWF5oJM3yfxdakLEIkJ%2Fr8w18YaFcLN%2B1jM6rIIwfKA ag7a%2B8roNZLAEyYGoDvMu95B%2Fhk1bms2loBzbgFgT9%2FD sA4tAvrDQJi3JLUyzP8dKomb021w2pak%2BdvcvYUogR0xFZO% 2BLlQ%2BqvN6xNxfR4KalitU4o2vlYTInhOUaIbU%2FqL9Gug8 mFW7XusVxVYA7ZnX3B9BDM62moLuNPZJjpP5YTPtima9Iu%2FB X83SzUNJRCafcU2rHszCfQU7kcMzvcF5GebPAq%2FBFBvrzejn Yx%2FRZLH7W84PzDhLb7fqKtpqt1mO34u1AUzWG3R3dcsLnZ7t OcXFVPZjVzajHjjXOrZkVxMZnsvFO5ROf0ceyWek59ijGDFk9K UViCooTg%2FeS4hCsXrFm8Xavo2ZOHBo2pDRNEC0HLsxwAL8a2 srVUWimmhVW%2FvMZThiYbzK37PPyB%2BZ5eZYn5jVZmUimhPS I%2BRHp17AsN%2Ftmf7Cotls2OTURxzpIqi88O1gCGh7o45xSv mfS8wlB54ZHmy5JYV0BVe2&checksum=3334375580547373436468cb4a91afd297d8c6335 210

[Vince]

Thanks for everything guys, I've ordered a couple of Mundorf 8.2uf for £22. That's with UPD next day delivery.
I'll see how it goes and let you know.
Thanks again and stay safe
Vince

[Vince]

Hi all,
I've fitted the Mundorf caps inline from the speaker terminals. They sound very impressive, very loud though, so I've ordered 2 mono L Pad attenuators. These should help me get the level I want. I want them firing up, just sat on a Vibrapod on top of speaker to give an even better sense of air. I will try different angles and see how I get on.
Thanks again for the advice and I hope you are all staying safe and well
Cheers
Vince

[grog]

you need to check the impedance at 2.5khz and calculate the capacitor value based on that,
use a reasonable polyprop film capacitor until you are very sure on value,
a lot of the change in sound between capacitors is down to tolerance, even many 'special' ones have +/- 10% that's a significant change in Xover frequency,
this at £4 would be a great place to start, https://uk.rs-online.com/web/p/polypropylene-film-capacitors/6842251/

[sailor]

Hi Vince,

What speakers are you trying this on?

What crossover does it have?

When fitting L-Pads and have established the correct level may I suggest you measure the series and parallel resistances in circuit and then replace these with quality resistors of the same value. Avoid those ubiquitous square white ceramic monstrosities. They sound horrible wherever they are used including power supplies. Consider Mills which are smooth or Powertron, (a Vishay foil) which are very detailed.

I have recently upgraded the crossovers on my OB speakers which use the Silver Iris tweeters and have the original caps available if you would like to try them. Rated 6.8uf, they will raise the XOfreq. slightly but I think you will have better results with a much higher crossover if the idea here is to add air and spaciousness.

Buy me a guiness and you may have the caps.

The link below although it is not mentioned is Linkwitz/Riley behavior.

https://www.parts-express.com/resources-crossover-component-selection-guide

Have fun