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Conversion of Monitor Audio Monitor 11 to Active Crossovers


bencat
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Glad it's worked out Andrew - well implemented DSP has improved all the speakers I have tried.

Any cynic who has never heard what it can do should visit your setup at Kegworth.

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Well I tried to do what I said and just play music throughthese speakers but I have to say the temptation to try yet another measurement and create yet another filter set is very strong .

So I have tried a few more options . Firstly I have tried the set with the each amplifier driving a single channel . This was not a good idea as there seems to be an output difference between the two amplifiers (I know they are both 405 units but it is there) . So after much measuring and trying abandoned this as it just did not sound as good as using one amp (the most powerful output of the two for the Bass and the other for the treble )

Then I have spent two days while I am not in work taking repeated measurements for each individual drive unit (Bass Left , then Bass Right etc). Using REW and with the Crossover Settings on the Output channels to bypassed this should enable me to do a measurement of each set of drivers and then create filters for each unit . Brain tells me this is the most thorough way to do it and should produce the best and accurate settings . Sadly probably because i have issues with the settings and i am not sure what paramters I need to change I can not get these various filters to work as they should .

Instead I have connected each speaker as a full unit with CR bypassed and tested this from 10 - 20000 Hz and then generated a filter fro each side and put this on the Input channels .

Doing this has restored the smoothness and intergration that I liked in these speakers and the sound has again become what I want it to be rather than I think what mesurements are saying it should be .

When I get a chance and if someone is kind enough to donate their time I would like to go through the full individual speaker measurment and filter generation again and just check that I was doing things correctly . If after that i again get the same sonic results I will just accpet that for my system and for me ears how I have used the Minidsp works for me .

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5 minutes ago, bencat said:

Instead I have connected each speaker as a full unit with CR bypassed and tested this from 10 - 20000 Hz and then generated a filter fro each side and put this on the Input channels .

Not sure that this is going to give you the best result, or be safe for the tweeters, as you are going to be shoving bass up them at significant power. Nothing wrong with measuring the speaker as a whole and generating filters accordingly, but I would strongly suggest doing this with the crossover enabled, so although your REW sweep goes from 10-20K, only 10-(crossover freq) goes to the woofer and (crossover freq) - 20K goes to the tweeter. That way, the measurements you take will also reflect/correct for how well/badly the two drivers integrate at the crossover point.

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Please follow the advice Tony gives above... If you recall Andrew, when we first measured these speakers, I set an 8th order (48dB) crossover at 2khz to avoid potential damage to the tweeters.

As far as setting MiniDSP filters is concerned, I suggest that Tony would be best placed to advise as I am not familiar with that setup.

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Right I realise now once you wander in to this wonderland world it is very difficult to just fix things and stop . There is such scope for changing settings , crossovers , equalistion (also compression but not really looked at this) and it is so easy to change save in a seperate profile then listen and alter things while you listen .

Then you get the sight of another addition to bolt on and you read a little bit and the tinkering and fiddling demon inside you says you need this you have to find ot what it does.

So I have given in and bought the Dirac Live plug in downloaded yesterday and activated today . This seems to offer a very powerful measuring set up using nine different points around the listening position (or the room itself if you prefer) which  are then averaged and used to generate the in room equalisation that actually works with where nyou are rahter than a general curve to match the supposed flat response.

I am going away today for two days to the Lake district today and Saturday Liverpool are at home so most likely it will be Sunday before I can set things up and get started with new software. Once I have had a chance and produced the first setting will report back about how easy the software is to use and what the sonic results are .

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Right refreshed from my brief sojourn to the Lake District and still grinning after watching Liverpool beat the mighty Cardiff today was the day i set aside to get to use the new Dirac plug in . Getting the licence and getting the software loaded and set up is a bit of a faff but not too much of an issue. Little scary that when you first use it is resets the Minidsp but as I have saved all the files with eq and the like to a folder not the end of the world.

Opening the calibration tool and you get a very simple screen with a step by step list on your left the main panel with all the controls in the middle then on your right a panel with instructions and tips of how to proceed . In all honesty it could not be simpler. Before I made and measurements or did anything I went in to the output for each channel and made sure the right basic crossover points and type were selected and not bypassed as always made much simpler by linking the right and left channels bass abd treble so change to one is mirrored in the other.

Then it is a case of going through the various stages , choose the speaker (Stereo or mono) choose the Microphone then add Calibration file if you have one . Then set the test levels another pretty easy process start with output at its lowest and the input gain at its highest use the slider of the input gain to get abou 24 DB background noise , then increase the output gain until you are in the middle of a green bar . You do this for each Left and Right so it w.ill take in to account and volume differences .

Then on to taking measurements using either a single seat , Sofa or it says Autodorium . Tried both the single seat and sofa options and put them on config 1 and config 2 . Takes nine readings starting with at ear height in the listening position as the first one then in a rectangular pattern to each side and then above the normal listening position . I am sure if you wanted to you could get really accurate about this and measure each position and when my Wife has gone to work I might just take the time and effort to do the whole thing as tightly measured as possible . My feeling is that it will not make that much difference but you never know till you try .

Once the measurements are all completed the system does a calculation and shows you the measurement results and the target curve it has generated to bring the sound closer to flat but with a house curve that slightly boosts the bass and slopes the treble . Nice thing is taht you can pull this curve up and down at any point and switch it about but unlike with Minidsp it does not seem to let you do this while listening to music so you can hear the result on the fly . It may well do this but I will need to study the manual to find out how .

Then it is just a case of saving your project and then dropping the resulting file on to anyone of the 4 configurations and then loading them to the Minidsp .

So all in all a very easy and simple thing that I feel anyone could do and you can just keep everything as the programme generates and it will give good results.

Now the difference , well the EQ generated by the Minidsp using the REW files was good and made the speakers sound more of a whole with drive units and sound more intergrated . Dirac takes this to a whole new level the speed and snap of the sound is still very much there but now you get a much wider image with definite sounds locked in to the position they were placed when recording . Bass is tighter and at first you think it has reduced until some real bass comes in then you realise it is just giving what is on the track and were the level is low then thats what you get when it increases you get the bass but very controlled and tunefull to my ears not any boom or one note bass but very clean and easy to listen to on its own if you want to .

To my surprise there was a very different result for both the single seat and sofa filters . Single seat had a much more focused and strong central image with width but very much behind the cental singer or soloist . Sofa filters gave a less strong central image but greater width beyond the speakers and seemed to move the back images closer to the central soloist almost as if they were in a line rather than curve . Given how a group would set up for a live show the Single seat is possibly the more accurate but I find that prefer the sofa setting even though in my listening room it is a single chair that I have.

I am glad that I started out with the standard Minidso 2x4 and worked through the use of REW as it taught me things about how changes can alter the final sound . I would say that the Dirac filters are much better than anything I was able to produce with the REW (if I did nine different measurements there and then averaged that out it may be similar to the Dirac but it would be lots of work) . The final results are still now an improvement with each change and the Dirac is such an easy product to use that I would say anyone could get really good results without too much fuss . Just remember that you need to have your crossover settings and put these in to the outputs before you use the Dirac.

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Hi Andrew - glad to hear that it is working for you - I haven't bought the Dirac upgrade yet, but what you have written is good encouragement! I discovered that my existing mic setup (Behringer measurement mic through a Behringer USB interface) isn't compatible with the Dirac upgrade, so I have bought the UMIK-1 (and now have a Behringer mic that is surplus to requirements!). 

As to the setup...did you just use the crossover settings in the MiniDSP, or did you also import the EQ and/or gain settings that you used before the upgrade?

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Hi Tony I had considered a few options before I bought the Umik but glad i went that way as it is just so easy to use with Minidsp . One of the things that happens when you first load the Dirac is that you need to restore to the unit to defaults and I think once you do this you have lost the general settings that you had from the Minidsp 2x4 . With the upgrade you are now using the DDRC-24 and its control panel .

So when I checked the config settings they were all at default and cr was bypassed . So I just put the basic crossover settings in as I know them off by heart now made sure they were not bypassed and left the EQ as basic.

Suspect you could reflash the unit back to a MiniDSP 2x4 and then load back up the configurations then reflash as DDRC-24 and then do your measurements and filters on top of your original filters . It will I am sure make a difference but putting EQ over EQ seems not the right thing to do for me as the Dirac is doing a complete room setting similar to the Dspeaker unit rather than just speaker treatment so as long as the crossover is in place then the raw speaker output seems best and allow the Dirac to filter the output as a whole .

I have no doubt I will come back to this another day and try a few different things to see what can produce the best results .

Edited by bencat
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Hi Andrew

That seems like the right approach to me too - as you say, not much point in overlaying one set of EQ filters with another. The one thing that I think would potentially help, though, is if you had used the gain settings to get the overall balance between HF and LF drivers right, it might be worth putting those in as well as the crossovers so the Dirac has less work to do getting the overall balance right. Dunno whether it is going to make any (audible) difference, but might be worth a try, especially as you can set up 4 different configs...

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Oh, and yes, you can apparently go back and forth between the Dirac firmware and the standard 2X4HD firmware as often as you like, according to the miniDSP forum - if you launch the 2X4HD plugin you can reset the 2X4HD and re-flash the original firmware - it is all built into the plugin software. Mind you, given your comments about the results you have had using Dirac, there's probably not much point other than out of curiosity, because you will probably want to go back to the Dirac version again. With my second (non-HD) 2X4 I can do that comparison very easily though.

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Hi Tony was planning to do another run (project) with the minus 1 db treble settings and save that as config 3 but given the stare i am getting from my wife I suspect this will have to wait for another day as you can easily lose track of time doing this sort of stuff and you always seem to come with an idea of just another set of measurements I should do with this changed and see what happens then .

Current ones seem to be fine and working well so will see what these are like to live with over the next few days and then try again .

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Hi Andrew - just got the Dirac upgrade up and running. Did a very quick and dirty test - all measurements taken from the same position - the results are really quite dramatic; significant improvement over the uncorrected response. I can see that this is going to be interesting!

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18 minutes ago, Tony_J said:

Hi Andrew - just got the Dirac upgrade up and running. Did a very quick and dirty test - all measurements taken from the same position - the results are really quite dramatic; significant improvement over the uncorrected response. I can see that this is going to be interesting!

I know what you mean Tony have been thinking about how to set out the measurement positions with a bit of precision and not really coming up with to many good ideas. Latest is to use a large poster pinned to the wall with the positions marked on and then align the Microphone to them . I think the most vital thing is to get the first measurment in the listening postion as accurate as possible then the others can be not quite as precise.

I know this could get a bit OCD so trying to resist doing it too much . I will however set aside a day when I am on my own and measure and fix each point and then see if that makes much of a difference . Will need to do one using the single seat then one using the sofa model .

Surprise to me is height of the Mic when aligned with my ear level . I could do with someone to measure this for me but have avoided asking Linda to do it really do not want to explain why . Rough guide sittong in my normal seat is around 125 CM whcih seems quite high but I suppose that I have to allow for the fact that I have very long body and not so long legs . Next session is going to have a bit of precision about it with equal heights fro all of the test points and equal gaps between them . Have also decided (I hate how this is starting to sound ) that I will remove the seat and my desk from the room so the computer is not in the way and I have more room to tightly postion the Mic at each point .

Edited by bencat
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Yes - getting the mic positioning right may well be a problem, so I  can see much playing needed. In my case I also need to move the whole kit & kaboodle to a more sensible listening room - at the moment I have the speakers set up in my study about 2 feet apart which is less than ideal. 

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Just measured the overall response with the Dirac correction filters active - pretty much ruler flat. Certainly much flatter than I have been able to achieve with REW alone. Which is very encouraging.

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