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TOPIC: Building my first Active 2 Way Speaker

Building my first Active 2 Way Speaker 1 year 1 month ago #37996

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Hello All

I have been a music lover since a very young age and have bought and collected many Hi fi systems that are used today . I have never really been part of the DIY scene but after having a room at a UK Hi Fi Show at Kegworth which is run by a UK Hi Fi Forum (www.hifiwigwam.com) I came across a number of other members demonstrating their own built Active speakers .

I decided that I would give this a try but realised that my woodworking skills and cabinet / Driver design skills were zero so I went the way of taking an already built vintage Speaker and working on that. A trawl of ebay turned up a pair of 1980's Monitor Audio 11 speakers which were ideal in that they were not too small so unable to deliver reasonable bass plus they were Bi Wired so giving the correct split for speaker inputs without any extra drilling and adding.

The outside of the cabinets were rough by solid so as a first step I removed all driver units and the Passive Crossover and after sdanding the cabinet painted it with Blackboard paint and then finished with beeswax . Not by any means a perfect finish but good enough for my wife not to object to them .

The passive crossover on these speakers was hard wired to a MDF board that covered a cut out on the back with the Binding posts attached so I needed to use this board to seal the speaker again . So I just snipped all the components connected to the Binding Posts and then solder the connectors direct from the drivers to the Binding posts Bass to the lower pair and Treble units to the Upper pair .

This then completed the physical work and went on to the measurement . Visited a friend and we set one speaker up in his garden then completed some sweeps with a microphone 1 metre from the units in free air .

I have included a few of the measurement graphs below for those who may be interested . Upshot was that we decided to put the crossover a 2k which represented a null and downward trend for the Woofer and strong rise for the treble.

To my surprise this worked well and produced music which sounded good even with just this basic work . It is my intention to put this Crossover in Config 1 on the Minidsp 2x4 HD and keep this as the baseline for any listening . I can then use the other three Configs to experiment with Filters , EQ whatever and compare them with the straight flat setting
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Building my first Active 2 Way Speaker 11 months 3 weeks ago #38640

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Well I have now completed my first Active speakers and today they made their first music . The speakers as indicated are a Pair of 80's Monitor Audio 11 Monitors they are not huge and are a sealed baffle two way unit . The passive crossover is fully disconnected but the board and components have had to remain as they form the back panel with the binding posts on at the rear of the speakers . Settings for the units are 48dB LR crossovers are bass 10hz to 1500hz Treble 1500hz to 20000hz . Trable units have been adjusted down to -1db compared to the LF units to get better bass intergration .

Firstly I was amazed that not only have I been able to complete this project from measurements through to crossover implementation to final reslut music .

With no adjustments to the initial crossover settings the sound was very good but a little too sharp in the Treble and light in the bass . Having the Minidsp plugged in to my Lap Top with a long USB cable I was able to play music and sit and alter the treble ouput and listen to the results and twaek things to get it woking better and for the sound to become really intergrated .

Result is exceptional . First thing I have noticed which is different from a passive speaker is the speed of the active . Notes start and stop with great speed and precision which gives music a real natural flow that I have not experienced with any passive unit . The sound changes with whatever the material is fed to it so you can easliy hear the difference between recordings and you can tell it is the recordings sound rather than any addition or subtraction of the speaker.

I need to now get to understand how to use the EQ racility on the Minidsp so that I can have a much more subtle control of the sound to fine tune and adjust it to how I want it to sound . If anyone has any suggestions or advice on what settings to put in as a rough guide to get me started it would be appreciated.

I realise that my project is quite modest compared to amny here and I do not have the technical skills or knowledge to read the graphs I am producung without help . But this is a very good thing for those new to this idea and way in which a fully working product can be made so easily without any previous experience .



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Building my first Active 2 Way Speaker 11 months 2 weeks ago #38686

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@Bencat

Great to hear on your first project as a success!! It always put a smile on our face seeing projects from our customers.. :-)
I'm sure that you're going to have much more fun over the years as you start tweeking and learn even more tricks..

Have fun and thanks much for sharing!

DevTeam
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Building my first Active 2 Way Speaker 10 months 4 weeks ago #38921

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Well happy as I was with the quality of the audio my active speakers were producing I do now find that it is very hard to just set and forget. So after a little reading and much resistance I finally gave in and have bought the Dirac Live plug in for the Minidsp 2x4 HD .

Ordered it yesterday and recieved the activation file this morning so now all set up and ready to start on my first measurement and filter creation. I am however away for two days on a short break to the Lake District from today and with Liverpool FC playing on Saturday I not going to be able to seriously get the software set up and used till Sunday .

Fingers crossed that the use of the Dirac is as simple as it seems having read the manual and I will be very interested to see how this could imporve on using the REW settings . Will get back next week once I have had a chance to look at and use the plug in .
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Building my first Active 2 Way Speaker 9 months 3 weeks ago #39376

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Well have to say i am blown away with how good the DIRAC Live plug in is . The difference it amkes to imaging and driver intergration is way beyond what I was expecting.

The first project with the Montitor Audo 11 units has gone that well that I have now given the speakers away and I am perparing for my second project using a pair of 1970's KEF 103 Reference speakers . This will take some time but I hope to have it completed before the end of February 2019 .

In the mean time the DDRC 24 (MiniDSp 2-4 HD plus Dirac Live) I already have is now being used in my main music system for the DIRAC Liver function alone all other controls by passed on a pair of Quad ESL 57 passive cr speakers and the result is excellent well able to cure the imaging hot spot of this speaker .

I would like to be able to buy another MiniDSP 2-4 HD to use for my new project but having a little issue getting any response from the UK Dealer Kalibrate . Despite e-mails and calls they do not respond so may have to look at buying from another European Dealer . If anyone has experience with the French / German ro Dutch MiniDSp dealers let me know .
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Building my first Active 2 Way Speaker 9 months 2 weeks ago #39495

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Wonderful update and glad to hear that you're having a great experience with your DDRC-24.. :-)

Have fun!

DevTeam

PS: BTW< sorry for the issue with not being able to get in touch with our dealer. We'll investigate. In the mean time, lots of great dealers in EU indeed..
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Building my first Active 2 Way Speaker 5 months 6 days ago #41814

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Just a short up date on how things progressed . While I was pleased with the results and sounds coming from the MA Speakers these were only ever a cheap trial pair to get me used to the MiniDSP DDRC 24 and not the end product.

Moving on from these units i decided to convert my favourite passive units that I owned a pair of 1975 KEF 103 Reference speakers. These have a veriosn of the KEF SB 200 Mid base drive and a purpose built large dome tweeter. They are also housed in a metal frame with a solid metal facia .

However they are only a single wire speaker so not only did I have to remove the passive crossover from the cabinet I also had to make space and holes for a second pair of speaker binding posts so that the Bas unit and the tweeter unit had a seperate connection. As the rear plate was a hard plastic moulding with a very odd curved shape this proved to be more difficult than I expected and in the end burning a hole and then reaming it out with a screw driver head proved the best option. Once smoothed and then filled with a plastic screw binding post which gave good seal (these are sealed baffle units) Iwas able to then move on to the crossover .

KEF being a very professional and helpful company provide me with a full specification sheet for both drive units measured by them in a full aechonic chamber to a very high degree of accuracy so all I had to do was transfer the crossover point 3000 hz for the Treble unit to the MiniDSP and things were set up .

Next was the setting up and running of a full DIRAC Live sweep with accurate and measured points for each of the 9 sweeps with very close attention paid to the accuracy of the intial listening position sweep .

Then on to music and using the MiniDSP as both Crossover and DAC and pre amp with direct feed in to two Fidele Modified Quad 405 power amplifiers I played music through them for the first time . The result was wonderful and most musical the speed of active units was evident and the power of the bass was really noticable . I liked the Kef's as passive units , as active spekers they grew and produced some of the best music I have heard for a very long time . If you have any doubts about making the leap to try and convert spekaers to active then forget them it is not only much easier than you think but the final result will be so much better than you dreamed.
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