TomW Posted January 8, 2017 Share Posted January 8, 2017 (edited) For the January meeting of the Sydney Audio Club we are very pleased to have dedicated Sydney Audio Club member, Graham Allen, present the large reference version of Linkwitz kit speakers. These DIY speakers are one of many products created by Siegfried Linkwitz (refer to his website at http://www.linkwitzlab.com/index.html). Siegfried Linkwitz has over 40 years of experience in loudspeaker design, electro-acoustic system design and the perception of sound from loudspeakers in normal rooms. (As well, his name is one half of the respected Linkwitz-Riley crossover filter). In our September 2015 meeting, Graham presented a pair of Linkwitz Lab LX Mini speakers. They offer very good sound for a very modest outlay of money. This month, Graham will be demonstrating his recently completed Linkwitz Lab LX521 speakers. Refer to http://www.linkwitzlab.com/LX521/Description.htm. These unique speakers, designed by Siegfried Linkwitz, are wide range 4-way dipoles using per channel; 2 bass drivers, lower mid, upper mid and tweeter drivers. They should be quite capable of filling our club meeting room with a high quality, well imaged sound stage. Graham’s speakers are the LX521.4 4-way version with digital crossover, and are built acoustically identical to the published Linkwitz design, with some minor changes to the appearance to suit locally available materials. The timber used is Australian river red gum, with the baffles and baffle support shelf made from solid stock, and the side supports made from marine plywood covered with 2mm veneer cut from the same plank. The river red gum is finished in an oil based varnish. The bass enclosures are made with marine plywood, painted with a textured satin black. (See the photos of Graham's own speakers below this message.) Graham will give a brief technical description of the LX521 design approach, explain how they were constructed, and demonstrate the speakers on a range of music. For his presentation, Graham will use his laptop with JRiver as a source (via a USB streamer to the miniDSP 4x10 processor). Details of the system…. Linkwitz Lab LX521 speakers – These reference quality speakers offer articulate bass reproduction due to reduced coupling to room modes, neutral timbre and fast time response, low non-linear distortion and high instantaneous dynamic range, optimal spatial rendering of the stereo phantom image. Amplification – The LX521s will be driven by an 8 channel, 180W per channel, Hypex class D amplifier, using the UcD180HG amplifier modules https://www.hypexshop.com/DetailServlet?detailID=2151 and SMPS400A180 power supplies (4 separate power supplies) https://www.hypexshop.com/DetailServlet?detailID=3140. Crossover duties and digital signal processing will be handled by a MiniDSP 4x10 Hd https://www.minidsp.com/products/minidsp-in-a-box/minidsp-4x10-hd. The miniDSP 4x10 accepts digital and analogue inputs. Oppo BDP-105 Universal player – We will have an Oppo on hand for our BYO session. Refer to https://www.oppodigital.com/blu-ray-bdp-105/ and http://www.theabsolutesound.com/articles/oppo-bdp-105-universal-blu-ray-player-and-dac/ The second half of the music sessions will be our popular BYO. Members and guests are welcome to offer music to share with us all. So bring along your favourite music on CD/SACD or USB flash drive. (Sorry, no vinyl this month) All we ask is that the music and recordings be interesting. We'll ask you to tell us a little about the artist/recording before it is played. Tracks over 6 minutes will be faded out, to give everyone a fair go. Whether you are a novice or a seasoned veteran, you will have the opportunity to listen, learn and share your experiences with others. Feel free to come and hear the capabilities of the system, or to just share the experience with like-minded music lovers in a friendly and relaxed atmosphere. Guests are welcome – we are a very friendly club so you don't need to know anyone to join us for an afternoon of fine music and sound. Venue: Epping Creative Centre, Dence Park Address: 26 Stanley Road, Epping When: Sunday 15th January 2017 Doors open 1pm Meeting starts at 2pm Best regards, Tom Waters President Sydney Audio Club www.sydneyaudioclub.org.au tomwaters@sydneyaudioclub.org.au Edited January 8, 2017 by TomW Fix spacing between lines Link to comment Share on other sites More sharing options...
TomW Posted January 8, 2017 Author Share Posted January 8, 2017 Link to comment Share on other sites More sharing options...
TomW Posted January 17, 2017 Author Share Posted January 17, 2017 (edited) Just my usual follow-up after our club meeting on Sunday. Attendance numbers at our January meeting is sometimes on the low side… people are still on holidays after Christmas. However, this time we had a medium sized crowd attend (about 30 people in the first half) – I believe they were enticed by the promise of Graham Allen’s speakers and system. We have some keen DIY members in the club and a couple of the guests appeared to be into it as well. They were all keen to hear what the reference Linkwitz speakers could do. Where else would you go to see and hear them..! The speakers looked very professional and sounded very good. I believe most people were impressed, judging by the comments on the Feedback forms. While the meeting is on, I usually stand and move around the room – I was impressed by how balanced the speakers sounded regardless where I was standing in the room. Perhaps that is due to the dipole arrangement of the drivers. Of course, setup is all important. Before most people arrived, Graham experimented for at least an hour – he tried the speakers forward - back, toed in - straight ahead, close together - far apart. It was sounding good, but Graham noticed a persistent imbalance between the left and right, so we centred everything relative to the centre of the room. That made quite an improvement, but then we had to experiment again (!) with speakers forward - back, toed in - straight ahead, close together - far apart, etc...! But it was definitely worth it in the end. As I mentioned in the above meeting notice, Graham built the Linkwitz LX521 speakers from plans purchased from Linkwitz. He’d ordered the drivers separately, all were manufactured by SEAS in Norway. People were curious about pricing and the build time. The parts alone for the speakers and amplifier cost around $6000 – that includes the plans, license (from Linkwitz Labs), materials, drivers, shipping, customs and duty. A sizable chunk of money, but very reasonable given the sound quality. The build time for the speakers was around 100 hours. The Hypex amp modules cost about $100 each and power supplies about $130 each. Graham used 8 amp modules (his speakers are 4 way speakers and each speaker needs 4 amps). All the amp modules were housed in a single chassis. (You could put the amps inside each speaker - Graham chose to not do that, he stuck to the Linkwitz plans.) The miniDSP unit handled the x-over duties – 8 XLR connectors went out to the amplifier, and 8-way 13 gauge cable to the speakers. We didn’t have our usual Members Music Session. Instead, member Eddie Howe demonstrated the streaming of MQA files from Tidal. Regular attendees will know that we don’t have hardwired internet connectivity at the hall. So for Eddie’s presentation, we used the 4G in a phone to talk to Tidal. At first we had issues with this, but once we switched to a mobile on the Telstra network (stronger in the Dence Park area), it all came good. We played 3-4 tracks. The purpose of the presentation wasn’t about sound quality – we weren’t comparing the SQ of the streamed tracks from Tidal to equivalent downloaded files on Eddie’s MacBook. We just wanted to demonstrate that you can indeed now stream MQA files from Tidal. Keep in mind that the high-res MQA file size is about the same size as a CD quality FLAC file, yet promises to be better than or the equivalent of a 24/192 non-MQA FLAC file in sound quality. So this is quite a feat and very beneficial if you are streaming. A huge thank you to Graham for his thoughtful and comprehensive presentation. And lastly, I’d be remiss if I didn’t extend some recognition to a fellow from Canberra that came up primarily to attend our meeting – thanks! Here are a few comments from the Feedback forms: "Easy to listen to.“ Very natural. One of the very best sounds ever! “Meeting great as usual." "Speakers (IMHO) were better than many famous manufacturers. Effortless power, matching the speakers well. “The electronic x-over was excellent as a preamp." “Meeting was well organized. Great quality of gear. Different music tastes great. Speakers were very nice and "out there", beautiful, looked good.” “My first meeting, very enjoyable. Very interesting gear. Music not all to my taste. Not clear about how Hypex amps sounded. Sound very promising, realistic I thought.” “Speakers great, very well balanced.” "Very well run meeting. System great bang for the buck! Speakers had great range, very open.” “Speakers had great sound, great value for money.” “Excellent meeting. Very impressive speaker, backed by very fine digital things! A great way to start the year. Speakers were a great achievement - 100 hours to build and $6000 - bargain!” “Great DIY build. Graham is a very clever and patient man.” “Well presented and informative. Impressive and musical system.” “One of the best sounds we have had in a while.” “Good start to the year. Well done Graham!” Edited January 20, 2017 by TomW Fix spacing between lines Link to comment Share on other sites More sharing options...
aab Posted February 17, 2017 Share Posted February 17, 2017 I've been wanting to hear these ever since I first read about them. A very interesting design. Shame I missed out. Build quality looks excellent - well done Graham. Anthony Link to comment Share on other sites More sharing options...
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