Interesting video about designing out speaker shortcomings

Dedicated to those large boxes at one end of the room
vinylnvalves
Old Hand
Posts: 1074
Joined: Sat Jan 26, 2013 12:08 pm

#16 Re: Interesting video about designing out speaker shortcomings

Post by 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
Old Hand
Posts: 1074
Joined: Sat Jan 26, 2013 12:08 pm

#17 Re: Interesting video about designing out speaker shortcomings

Post by 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.
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#18 Re: Interesting video about designing out speaker shortcomings

Post by 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.
"Once you find out ... the Circumstances ; then you can go out"
vinylnvalves
Old Hand
Posts: 1074
Joined: Sat Jan 26, 2013 12:08 pm

#19 Re: Interesting video about designing out speaker shortcomings

Post by 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
Thermionic Monk Status
Posts: 5600
Joined: Thu May 24, 2007 11:22 am
Location: People's Republic of South Yorkshire

#20 Re: Interesting video about designing out speaker shortcomings

Post by 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
Shed dweller
Posts: 2556
Joined: Mon Feb 22, 2010 7:29 am
Location: Sheffield

#21 Re: Interesting video about designing out speaker shortcomings

Post by 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
User avatar
Ali Tait
Eternally single
Posts: 4373
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#22 Re: Interesting video about designing out speaker shortcomings

Post by Ali Tait »

simon wrote: Fri Feb 19, 2021 7:05 pm 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..
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#23 Re: Interesting video about designing out speaker shortcomings

Post by 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.
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
andrew Ivimey
Social Sevices have been notified
Posts: 8307
Joined: Mon Jun 11, 2007 8:33 am
Location: Bedford

#24 Re: Interesting video about designing out speaker shortcomings

Post by andrew Ivimey »

Oops! of= or.
Philosophers have only interpreted the world - the point, however, is to change it. No it isn't ... maybe we should leave it alone for a while.
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#25 Re: Interesting video about designing out speaker shortcomings

Post by 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.
"Once you find out ... the Circumstances ; then you can go out"
User avatar
Ali Tait
Eternally single
Posts: 4373
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#26 Re: Interesting video about designing out speaker shortcomings

Post by Ali Tait »

andrew Ivimey wrote: Sat Feb 20, 2021 12:30 pm 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. :)
User avatar
IslandPink
Amstrad Tower of Power
Posts: 10041
Joined: Tue May 29, 2007 7:01 pm
Location: Denbigh, N.Wales

#27 Re: Interesting video about designing out speaker shortcomings

Post by 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 !
"Once you find out ... the Circumstances ; then you can go out"
User avatar
Ali Tait
Eternally single
Posts: 4373
Joined: Fri Jun 08, 2007 8:10 pm
Location: Galashiels

#28 Re: Interesting video about designing out speaker shortcomings

Post by Ali Tait »

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