Interesting video about designing out speaker shortcomings

[vinylnvalves]

Just ran the driver through the box calculator. For a sealed arrangement, medium stuffing. A 13 ltr box would give you an f3 point of around 70hz and an f6 of 42hz, so integrating a subwoofer would be easy, mirroring the filter slope of the sub to match the roll off of the sealed cabinet. Almost talking myself into it

[vinylnvalves]

As an aside I do wonder if something like this https://josephcrowe.com/products/dual-m ... eo8-planar would be better giving a single driver over the critical freq range.

[IslandPink]

So much data here !
https://www.erinsaudiocorner.com/driveu ... _ptt65w04/
Shows the results of the science and development, when you compare it to some of his other tested units.

[vinylnvalves]

As no group buy..https://www.ebay.co.uk/itm/Purifi-PTT6- ... %7Ciid%3A1. Not sure how much you would get charged for importing them though.....as we are now the leper’s of Europe.

[simon]

Good question. I suppose 20% vat? Then there would othe "handling" charge. But one wouldn't have to pay vat in the seller's country presumably? lt used to be a lot easier!

[chris661]

They're really interesting drivers, although the cost is quite off-putting.


If anyone's interested in getting lots of bass from a small box, Kartesian Acoustic are doing some cool drivers. I have a pair of their ferrite 4" drivers here, which get down to the mid-30s in something the size of a shoebox, when used with a PR.
They use high-tech motors and the spiders look quite interesting - the outer waves are much larger than the inner ones.

Of course, with a 4" driver making decent bass from a small box, the efficiency is in the gutter. It's neat trick, though, if you've got some power on tap.

Chris

[Ali Tait]

Good question. I suppose 20% vat? Then there would othe "handling" charge. But one wouldn't have to pay vat in the seller's country presumably? lt used to be a lot easier!

Just bought a Decca C4E from Japan for £218. Had the pay DHL another £62 to get it..

[andrew Ivimey]

Did you ask DHL for a breakdown of just get very depressed?

I was in cloud cuckoo land over this thinking I'd just be paying extra on items from Lithuania to Lisbon.

[andrew Ivimey]

Oops! of= or.

[IslandPink]

Thanks for the link above, Steve. Need to get on to this. Just debating whether to go for the ±10mm or ±10mm ones for Jon's project.
I will start a separate thread on enclosure options, as I have now modelled the Purifi 'Application Note' ported box, in addition to that MLTL option.

[Ali Tait]

Did you ask DHL for a breakdown of just get very depressed?

I was in cloud cuckoo land over this thinking I'd just be paying extra on items from Lithuania to Lisbon.

The latter.

[IslandPink]

You have always had to factor-in VAT from places like Japan, I have bought 2 or 3 camera lenses from there.
I also got a very expensive record from there once, but the seller took a chance and valued it at about 10 euros, that was nice but wouldn't have been if it had gone missing !

[Ali Tait]

Yeah, just depressing that it’s now the same from Europe.