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In Reply to: RE: Neolith has posted Excel Spread Sheet for magnepan speakers posted by Satie on April 25, 2017 at 20:26:55
Satie,
I will undertake some extensive testing via minidsp and REW and do some
frequency sweeps this weekend.
I already have the graphs from previous testing so it will be very interesting to see the comparison.
I want to make the following point re PEQs.
The PEQs were invoked via the minidsp.
Once I inserted the Lexicon into the chain I removed ALL PEQs and simply added the XO point along with the first order slope.
Thats it.
This combination with Lexicon has been a huge improvement to what I was getting before.
This has really confirmed to my mind the importance of an amplifier which has unconditional stability into a 2 ohm load when coupled with maggies.
The difference in sonics between the Lexicon and the other amps couldnt be greater.
I am so far very very impressed with the apparent brutish strength that the Lexicon has. It really punches way above its weight category.
The Lexicon gets very littl air time in Australia but is obviously well regarded in your neck of the woods.
My ideal outcome is however to have the capacity to switch from PASSIVE to ACTIVE. I want that option in case I wish to sell.
I have taken on board your recommendations in terms of XO figures. Its clear having the 2 ohm tweeter along with another 2 ohm super tweeter plus the series linked 8.5 ohm bass panels presents an interesting channel for a XO setup.
I think the original XO setup offered a lot of simplicity and obviously worked given the respect that the 1Ds still maintain to this day.
The Lexicon has offered a lot of potential in both the top and bottom end.
There is far greater extension into the bottom end to the extent that I almost feel like using a pair of subs which I would cut off at 40Hz given just how good the bass is at the moment.
The Lexicon is experiencing no issues in the HF and at greater than normal dB levels does not struggle with the upper frequencies. Absolutely no sibbilance at all. The previous brightness that was evidenced before has disappeared.
Follow Ups:
I think that the single amp passive crossover setup your restorers came up with is a good solution for resale.
The DSP makes it all very easy to biamp and I presume you got a set with more channels for triamping.
The fortuitous acquisition of the Lexicon amp appears to really have impressed you with the capacity of a solid conservative design that is carefully voiced for sound quality rather than bench test numbers. Though I always found those to make an obvious difference in SQ, many stick to spec reading as the sole guide to amp selection.
Satie,
Absolutely mate.
My focus is ultimately in adding the true ribbon as a supertweeter and I also think that a 5k cutoff on the existing tweeter would be prudent.
To me that makes it easy for the next person, if there ever will be one to acquire my setup, to simply run a single amp for a 3 way passive setup.
My minidsp was custom built by a good friend of mine. Its an 8x8 board which has a whole heap of balanced and unbalanced inputs and outputs.
It can facilitate a 4 way active setup which includes subs.
I think its been done very well and will post a link for it. Its amazing what you can achieve for this type of build.
The Lexicon has been superb. I am so over the smoke and mirrors that seems to pervade this entire industry and which it has to be said has been fueled by audiophiles who only look at data points.
The bottom line is that if you have maggies then an amp which can handle the heat that a 2 ohm load is what I first look at. I have seen so many amps where you pay serious money that bleed out the harder the load becomes.
This is a definite keeper. I am yet to confirm but I think that the current tweeters are actually 1.9 ohms. When you think the type of real estate that is covered by this tweeter from 1100Hz and above that is a mean effort for the Lexicon to cover as a permanent load. It not only hasnt skipped a beat but gives spades in SQ. I would describe it as a very honest amp which should be considerd by any maggie owner out there.
Ozzie
I think that the single amp passive crossover setup your restorers came up with is a good solution for resale.
The DSP makes it all very easy to biamp and I presume you got a set with more channels for triamping.
The fortuitous acquisition of the Lexicon amp appears to really have impressed you with the capacity of a solid conservative design that is carefully voiced for sound quality rather than bench test numbers. Though I always found those to make an obvious difference in SQ, many stick to spec reading as the sole guide to amp selection.
Hi guys,
As some of you are aware there appears to be an ambiguity in terms of the measurements that I am getting for my T1D tweeter panels.
I have put a multimeter across the wires which yields a figure of 2.25 ohms.
This is independent of the caps and inductor.
Does anyone know what the tweeter driver should measure BY ITSELF for this speaker as I am going to go back to the repairer and seek resolution.
I received an email today from him which contained the following information:
"Regarding your concerns with the tympani tweeter impedances , I saw these being rewired and it is nigh impossible to get the number of runs wrong as the magnets dictate where the wires run and that is a fixed parameter .
The wiring used was the same as the original as there is a colour code on these very thin wires indicating the gauge .
Could it be that some other parameter is confusing the reading ?
Also keep in mind that a multimeter - set to Ohms - does not read impedance , it merely gives a DC resistance reading . It is a very confusing aspect of audio theory that both resistance and impedance are measured in Ohms but are quite different parameters .
Impedance is a load consisting of a combination of inputs , ie. Capacitance , inductance , frequency , and , good old Pi (3.141...-.) ."
I understand that each speaker as a whole is rated at 4 ohms impedance.
However what does the individual tweeter driver measure?
I am getting the distinct feeling the repairer is seeking to avoid fixing if there is an issue.
I want to first make sure I have my measurements correct before I go back.
If someone has a pair of T1Ds and can measure the tweeter drivers I would appreciate any feedback.
Cheers Ozzie
As you now have increased the mass of the bass wiring, it is of no surprise that they go lower. The fundamental resonance is lower in freqeuncy and probably the peak in the bass is larger. It means the diaphragm will hit the magnets earlier.
Edits: 04/27/17
Roger,
Absolutely mate.
I've had an opportunity to hear the 20.7s and 20.1s so I know what the bigger maggies are like and I can honestly attest to my personal experience being that the bass on these speakers is superior to the aforementioned ones.
I have listened to 20.7s coupled with a pair of DWMs with some highly rated amplifiers which struggled under the load and was not overly impressed.
I live 5 minutes away from the hifi shop operated by the national distributor of maggies in Australia so I have heard ALL the current maggies that are available.
I think the best way to describe the differences in the range is that as you move up so to speak the next speaker gives you a bit more of the same thing as the previous iteration.
So in other words a 20.7 and a .7 will offer you that wonderful, spatial almost atmospherice imaging that is signature to maggies but the 20.7 will give you so much more of it which is more palpable to your hearing.
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