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:

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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.

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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.

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OK, we know that simple on axis, straight into the speaker frequency measurements aren’t the whole story – getting a range of measurements at different angles gives a better idea for speakers getting general use, not the whole glued to the magic sweetspot that a lot of hifi has.

So it was time to do some directivity measurements. I don’t have the a licensed copy of ARTA so I can’t do the heatmaps ala Gainphile’s site – but at least Room EQ Wizard is a nice free package that makes it fairly easy to overlay lots of frequency response graphs in different colours.
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I wanted to try some different waveguide options besides the FaitalPro LTH142 before I start making enclosures – and noticed the Pyle PH916 was a quite decent looking, inexpensive, candidate – but very little information about people using it at all on the web, unlike lots of other waveguides. But it is sold as a constant directivity waveguide, and in fact the waveguide I use in my Econowave speakers is a smaller model from Pyle so I gave it a try.

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Well I had made a shortlist of all sorts of great drivers to work through the cabinet simulations with, including the B&C 15TBX100 (Italy), BEYMA 15B100/R (Spain), RCF LF15N401 (Italy), Selenium 15WS800 (Brazil), and even some from Lorantz (Dandenong, Australia), though the Lorantz ones were out of my budget, despite being locally made.

But I got very lucky with ebay and scored a pair of Lorantz 15″ C390X B1 for a great price. I’m told these are asbolutely amazing quality speakers.

Conveniently the auction even included some PA cabinets – though not great for loungeroom use long term at least I can get some instant gratification and get started with measurements and integrating the speakers before I start the big task of building some nice permament enclosures. When placed upside down they even position the speaker quite close to the waveguide, which is how I want the new cabinet to have it.

Not measurements yet. I’ve just quickly hooked up the bass drivers with some temporary banana sockets connected via the bass reflex port.

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Build Intention:
A “simple” two way speaker with the advantages of the Econowave, but deeper bass than my current woofers, and more directivity by using a compression driver/waveguide that extends down to a lower frequency.
Eventually building the speakers with “modular” cabinets, to make changing parts easier.

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