At long last the enclosures for the Lorantz 15″ woofers are (mostly) done:
Big thanks to Col for helping with the build – his expertise gleaned from the multitude of enclosures he has created was a big help in streamlining the assembly process.
After a very long delay I’ve finally gotten around to working on better cabinets for the Lorantz woofers that will unleash their full potential. Having adequate enclosures so I could be lazy and use the speakers as is no doubt contributed to the delay, but also some non audio related stuff got in the way as well, as happens.
boards assembled to check but not glued yet
A simple build of one of the basic JLH 1969 Class A kits into a dumpster dived old amp chassis.
Used a 120W SMPS after reading in the DIYaudio forums lots of people getting positive results combining this older “classic” DIY design with modern quality switched mode power supplies.
I decided to build this to dabble further with Class A amplifiers after being quite impressed with a very well made DIY S.E.T. Class A valve amp I got to loan. One of the few gear changes my wife has made unsolicited positive comments about the sound.
After reading the diyaudio forum thread I ordered some of these low cost units to play with. So far I have been pleasantly surprised how good it is, and how little electricity it uses.
The current 139 litre volume of the cabinets I’m planning need a two 100mm diameter 24 cm bass reflex ports to tune to my proposed frequency of 33Hz.. Any of the bass reflex tube products cost quite a few bucks to send over to Australia unfortunately. Thanks to the useful suggestions of Stereo.net.au forum members, I got the idea of making my own from PVC water piping, using a heat gun to form the flares. But I’m not so handy with being able to fashion them presentably well, so I went with a combined approach of using some less expensive fixed lenth 200mm long ports (the same kind from Altronics I’ve already used), with some 90mm PVC piping to make short extensions with flaring on the end.
Lucky I still had the offcuts from the ones I had shortened for the Econowave speakers so I could use that to check the dimensions were OK:
There aren’t many constant directivity waveguides for 1.4″ compression drivers, but one I had not been aware of until Paul Spencer and SvenR on SNA forums brought it to my attention was the 18sound Xt1464.
After reading up on it I found it online for sale (inc shipping) not too expensive at www.thomann.de. It did take ages to show up though, with very detailed notifications of the first and last 2 days of shipping, and nothing for the 3 weeks inbetween.
Did this mod over the weekend. It’s a bypass of the Behringer output stage to get a cleaner output from the AKM AK4393 DAC chip.
I’ve been running through ideas for some cabinets for the Lorantz woofers.
The current fairly rough PA cabinets that came with them OK, but I’m not getting the full bass the speakers are capable of.
I just revisited my tweaks to the DSE A2667 speaker (an OK quality cheap speaker commonly available second hand in Australia for about $20). This is because I had the loan of a WooferTester 3 unit from Col, so I could measure the drivers properly, and also had been given an extra pair to experiment with (thanks Gavin!).
TLDR summaryI made one additional adjustment to the crossover that made the response even flatter, by adding a 4.4uF capacitor to the LF portion to make it a 2nd order filter, while inverting the polarity of the tweeter.. but at the cost of an increase in measured distortion at about 3.5khz.