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I'm happy to report that I have an entirely successful addition of 2x subs to my active 3-way Maggies, using the magic of a miniDSP 10x10Hd unit! :-))So anyone who has had a bad experience "the big sub can't possibly 'keep up' with the Maggie bass panel" ... hasn't implemented it right, IMO. ;-)) This is not my expertise that has delivered this great result - the guy that supplied my subs knows how to program a miniDSP and also has REW and a calibrated mike!
When I sit down to "listen", I do this primarily with vinyl. I was worried that the A2D then D2A conversions involved in using a miniDSP unit as the active XO (instead of the analogue active XO I'd been using for 15 years) would degrade my listening experience ... so I'm very happy to report that I can't hear any negatives. But there are positives, compared to the analogue active XO. Sure, the filters are the same - but the advantage of DSP means you can correct measured in-room peaks to flatten the overall FR.
So the subs deliver flat to 20Hz - but actually go a bit lower than this (16hz usable). And the output from each Maggie driver has been 'DSP-tweaked' to be flat.
Subs are 2x 15" Dayton 'Ultimax' drivers in sealed cabinets, with 800w Hypex plate amps. (What is interesting about these Hypex amps is that they use UCD Class D modules ... but have conventional linear PSs!) Outside cabinet dimensions are approx 35" high x 15" wide x 24" deep (1.25" thick walls).
The subs cross over to the Maggie bass panels at 83hz (measured) - LP/HP slopes are both 24dB. Then there's the woofer/mid XO at about 400Hz (18db LP / 12db HP) and the mid/ribbon XO (12dB) at 3Khz.
The result is that:
a) you can't really tell the subs are on, but
b) my Frankenpans have suddenly 'blossomed' at the bottom end. :-))All it seems like is that the Maggies suddenly have developed an extended bottom end! Wow - what I have been missing out on, for 25 years!
I'm delighted to be able to say:
* "Three Wishes" off Roger Waters' "Amused to Death" sounds absolutely awesome with the subs!
* Bach organ music is likewise sensational!
* and the barking dogs on the first track of "AtD" still appear waaay to my right!So I think there is absolutely no degradation of my analogue source - which is what I was hoping would be the case.
Here are some pics of the room, my 'Frankenpans' and the subs:
1. Centre - showing the miniDSP 10x10Hd
2. Left sub & panels
3. Right sub & panels
Regards,Andy
Edits: 07/14/16 07/14/16 07/14/16 07/14/16 07/14/16Follow Ups:
The subs project a short image, compared to the 6 foot tall low bass image running without subs.How far are your maggies from the rear wall? They seem way too close for good depth IMO!
Edits: 08/09/16
That's an interesting and valid point, RS ... but not one I've noticed ... or thought about. I'll have to experiment.
Yes, unfortunately (due to the room depth) the panels are not out very far - maybe 3' from the front of the LPs and 4' from the back of the equipment shelf, above.
Andy
andyr wrote:
"The vital point to me was whether the A2D and D2A conversions in the miniDSP unit would degrade my vinyl presentation ... and it doesn't!"
I was also worried about the additional ADDA processing in my miniDSP (the simple one!). Many of us have spent a lot of money in DAC... Inside the miniDSP there are no high grade processors and there is not even a good analog buffer stage. I am using my miniDSP in place of the external crossover box of my 3.6 and feed two indentical stereo power amplifiers (one for each channel). Surprise, it worked far better than expected! I have no EQ, just a plain setting similar to the original external crossovers. Sure, the bass increased by about 1.5 dB, that is what the series resistance of the coils soak up. Still, I like the result and have not set back the level of the bass. Did a fine tuning by inserting a 0.5 ohm resistor on the ribbon drivers. I hope to replace the miniDSP with a proper analog line level active low pass crossover for the bass and a passive for the high pass.
RealStereo wrote:
"How far are your maggies from the rear wall? They seem way too close for good depth IMO!"
It depends on what you mean by "good depth". Do you mean something like a neutral presentation or one with an extra portion of artificial depth due to a large cavity/room behind your speakers? It also depends on room size how far from the wall you place a dipol speaker and how it is angled in respect to boundaries and listening spot.
IMO realistic depth to width ratio, of a large sound stage, of a symphonic classical work.
Looks like everythings really coming together.
How much equalization does the room actually require? You're only treating the peaks right?
Well, it seems not much. :-))
The guy who provided my subs and programmed the miniDSP unit (using REW and a calibrated mike - lots of sweeps!) said that the room certainly didn't need any bass traps. Which - happily - means that it is pretty well behaved.
When planning the room I used a THX Excel spreadsheet which I have, to calculate the optimum room dimensions - optimum relative to the one dimension which was fixed, due to Victoria's Planning Regulations. The listening room is on what you call the 3rd floor (with Ground being the 1st floor) and, in Victoria, in inner-city neighbourhoods, as you go up, you need to set further back from the boundaries. So 3.6m depth (12') was the critical room dimension - yes, very small! :-(( - so the width is 5.8m (19') and the height 2.8m (9.2').
The floor is carpeted, furniture is a 3-seater couch on the opposite wall to the Maggies and 4 other chairs:
The painting on the wall behind the couch is designed to stop 'slap echo' - I made it in 1989 for the last house ... it is made of 1" thick cork sheets as the backing, with 1/4" cork for the 'objects'. So it acts as a slightly absorbant covering on the rear wall.
What we saw on the REW graphs resulting from the sweeps was a few peaks ... so, yes, Paul reduced these. The net result - taking advantage of the miniDSP unit's ability to set the output level for each driver - is that I have a pretty flat response form 20Hz upwards! :-))
Regards,
Andy
How closely did you get the impulse respomse of the system to a single spike?
Sorry, don't know. I can't remember Paul doing this but I can ask him.
What frequency should this single spike be?
Andy
The impulse response is a time alignment measurement it does not have a freq.
Here is one for the Vandy 2Ce, a time aligned design.
Of course that's a near field speaker impulse response, not one for a room but maybe that's your question.When used for room measurements, IR does not show room modal effects at different frequencies so you don't know what frequencies are problematic by looking at it.
Edits: 07/18/16
I am not interested in room IR but driver integration and phase issues. Short time window in the listening area. Ideally the speaker would provide reproduction of a square wave as Dunlavy liked to demonstrate with his designs. In my mind, FR squiggles are small change and the $$ are time and phase coherence. Dynamic capacity and extension and ultimate spl are also more important in my book. Since DSP is available to fix these things in a speaker along with the room- see DEQX- that is where I want to see it applied successfully.
Franken-nice!
haha, yep, Franken nice is right
I experience good results with Anthem ARC correction/sub X-over as well---one sealed sub.Cleans up the 42 Hz resonance on my Maggie 3.6 and makes it sound 'faster'.
It's clear from reading that there are significant differences between various room/sub correction algorithms. Everybody seems to like Dirac, DSPeaker and Anthem, but the ones on mass market receivers (Audessey & YPAO and others) have mixed reviews.
And I heard great sub integration at THE Newport in 2015 with the 0.7's and some expensive JL subs with their own measurement & correction.
I will make a general observation: Yes, you can integrate subs with Maggies well. Best results seem to come from sealed subs & high quality DSP measurement & correction.
Edits: 07/14/16
Congrats, Andy! It's good to hear you got such a great result.
I can't say I'm surprised, though. DSP has gotten so good, and quite practical to implement.
Happy listening!
The vital point to me was whether the A2D and D2A conversions in the miniDSP unit would degrade my vinyl presentation ... and it doesn't! :-))
Regards,
Andy
That is still my concern.
My AD DA devices , 24/48 audiophile and 24/96 pro audio are distinctly not entirely transparent. But I do have a friend who preferred listening to vinyl on the 24/48 cycle to straight on. Something to be said for Musical Fidelity's voicing. I can add that the differences were far more pronounced in 1st order crossovers than in LR4 active..
At some point I am certain that DSP room and FR and particularly time correction will easily overcome the drawbacks of the AD DA cycles. We are possibly there already with the better implementations from DEQX and Lyngdorf, but it is very good to know that it is already there on the miniDSP HD products at least for some implementations..
My DSPeaker Dual Core Antimode 2.0 sounds better with a separate LPS but still not perfect so I use it only on the subs.
My analogue Pass Labs XVR1-3 way sounds much better in bandpass mode with some buffers removed, but still is just a touch opaque. A little work should improve it significantly. Stay tuned.
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