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In Reply to: RE: Tympani 1-D, IIIa tweeter and custom foil mids using DCX2496 posted by computerman on December 11, 2014 at 07:18:49
I don't think it is noise that bugs me, it is something else. Decimation and filter issues, both digital and analog that seem to be the prime cause of the irritation. None of these can be removed entirely from PCM playback, though they can be ameliorated by doing higher recording sample rates and better resolution (24 vs 16). I am tolerant of noise and to quite a bit of distortion. Even hearing it as distortion I can still enjoy music through it.
Converting PCM to DSD is like smoothing out the decimation error and the playback requires no digital filters and only a high freq filter. It avoids the chopped up transients that decimation creates. I always suspected that was the main problem of digital for me, with DSD smoothing it out and avoiding the bulk of analog filtration and doing away with digital filters altogether the bulk of the problem is hidden from the ear. The little loss of detail is not a big tradeoff. The clearer and more present high freq are a godsend. DSD sounds more like real music. DSD recordings are obviously better even as a source for PCM downsamples.
I am not particularly surprised that the Behringer sounded better than a high phase commercial analog XO. The Behringer does not have phase and you set it on 1st order. So if you are not particularly sensitive to digital artifacts then you would be better off using it. Mini DSP with upgraded parts was reported to sound as good as the Behringer. That does not indicate that a stock version would.
Is the Twin a DAC or ADC and DAC for a matching DAW? I have been looking at the Tascam DA 3000 as long time analog master users have been pitching or deep storing their tape machines in favor of this unit. It records 2XDSD and seems to have top quality sound. The chipsets and electronics are similar/identical to the Teac UD 501. The downside is that you have to play it from SD or USB flash cards so the convenience of PC audio is lacking.
Follow Ups:
Satie, below are the Impact Twin specs. It has been discontinued so that is why the price is down. It is an ADC/DAC DAW unit and firewire as well. It does have the advantage of utilizing a PC (in the case of Pure Vinyl Mac only). I read the article Steve linked to, and I am wondering if you have tube amps/preamps. That might explain some of what you hear using a DCX or similar DSP. Have you read the article? In addition, I find that playback of digitally recorded vinyl using Pure Vinyl and the Twin from my Mac to be quite pleasing. It might even be much better with a better quality DAC for playback. I think it might be worth your time to take a look at it before you purchase the Tascam, but the price is so low, you might just want to try it anyway.
http://www.tcelectronic.com/impact-twin/tech-specs/
Yes, I was using a tube preamp and had to tone it down to keep the max output from overwhelming the inputs to the Behringer. Even so, occasionally the transients from the LP were too much and would saturate the inputs. CD was easy since it has a real maximum. I was using a Garrott FGS or the smaller one (S?) with the Shibata (before I had the FGS stylus put in) which is a very lively and detailed MM. My phono stage has ample gain and today I take down the output by 14db with an L-pad to avoid overloading the SS preamp's input, which is limited to 10V.
I am changing the PLLXO/active hybrid I am using right now too often to have it be driven by the tube pre with its highish output impedance. The SS pre stage is good.
The midrange amp was a tube amp. But I tried it with SS too and the sound issues remained. Aside from having digititis it also sounded like a pro audio device.
Hope everyone is having a great Christmas Holiday. I was wondering what the opinions are on fuses? I sent the second panel in and it is being rebuilt the same as the first. Even though the mylar on this one seemed in pretty good shape, Sheila suggested replacing it so that they would match. Now the question is, The original fuses on the tweeters were 2.5A fast blow AGC-3 and I saw on a picture of 20's that it used a 5A AGC-3 fuse for the mids. What are some thoughts on this? I have some pretty high quality fuse holders that I used for the tweeters, and the same can be used for the mids. Any thoughts would be greatly appreciated.
I'm sorry not to be able to help here since I am fuseless.
:" Look ma...no hands" followed by crash sounds...
Congrats on the revitalized IIIa's
I think the big thing is to have your tweeter near the mids and then the mids near the bass - meaning in the middle. then you do an equidistant arrangement and it should all focus well.
Most folks who use 3.x with tympani panels just run the Tympani bass as subs, in which case the arrangement of tweeters in mid 3.x bass and T bass out or placed for wall reinforcement would be the way to go ( using a 4 way XO.
Is there really that much difference leaving out the fuses? Is it safe or a little dangerous? What precautions does one have to take to not use fuses? Why does Magnepan use them even on their most expensive speakers? Are people really that careless? I guess I can answer that question myself.. as I blew both fuses on my tweeters, which were traded out not long ago, so they are quite new. Hate to see that money go down the drain. I am using 2.5A as were the originals. Is that too low? Plus that and the combination of the cryo'ed fuse holder should make for good performance and safety I would think. But sometimes my thinking is flawed in this area especially. :) Any comments would be greatly appreciated. I am sure there are lots of pros and cons.
You took out the original fuse and holder. You have done a mod that is safe and likely got most of the performance improvement you can get from removing the fuse altogether. If you are bothered by possibly leaving potential performance on the table, then why not just bypass the fuses and holders with a wire and listen that way for a while. So long as you don't change the amplification and listening volumes etc. you should be safe - as you had not blown a fuse with them recently in that configuration.
My source components are on a battery UPS so that brownouts etc. don't end up with something upstream turning on on its own. That also leaves time for me to shut down anything that was on in an outage.
I only use amps with delay relays on the tweeter and adhere to the turn off/on sequence religiously, like keeping kosher, so that the 10+ years since I took the fuses out I have not cooked or blown the tweeters despite making big mistakes like feeding the tweeter amp the bass output from the XO.
The midranges I use can handle 100W RMS and are 96 db sensitive, If you are feeding them any significant amount of power they will let you know well before they blow.
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Finally, it took a while and a long wait but my IIIa panels with custom installed factory foil for the mids are here. Wow they did a beautiful job. The frames even look new. They replaced the mylar and cleaned up the frames so that they look new. I cannot say enough for the quality of the work Magnepan has done on these. It is truly top notch!
Now the next question is which way is the best way to install the panels? It has already been suggested that the tweeters should go to the outside, next to the T-1D panels. With that understood, it could be either of the following for placement....
At the outside we have two T-1D panels, tweeter, mid, IIIa bass; or it could be two T-1D panels, tweeter, IIIa bass, mid. To reverse the placement of the tweeter, I can just swap sides with the entire frame. Hope that all makes sense. It is quite versatile and would love to hear some suggestions.
Repost in appropriate spot
Congrats on the revitalized IIIa's
I think the big thing is to have your tweeter near the mids and then the mids near the bass - meaning in the middle. then you do an equidistant arrangement and it should all focus well.
Most folks who use 3.x with tympani panels just run the Tympani bass as subs, in which case the arrangement of tweeters in mid 3.x bass and T bass out or placed for wall reinforcement would be the way to go ( using a 4 way XO.
I did plan on using the T1-D's with a four way X-over, but was not sure about the X-over points.. I was thinking 30 to 40 Hz, with a X-over point of 200 or 300 Hz, What is your take on that?
If i set them up like you say, then the T-1 D's would be towards the side wall, with maybe one panel paralleling it and out from the side wall (depending on the amount of room as I have not been able to measure the new apartment yet). then the bass of the IIIa, mid and tweeter on the inside? Do I have that right? Sorry for the confusion, I just want to be very clear as you guys really seem to know your stuff, and why waste time getting it wrong? :)
Yes you have the arrangement right.
The best bass xo is probably higher than 50hz and the IIIa bass to mid XO depends on how steep you run it. If steep then 200-250hz is likely good, if low order then you probably want 400-500 hz.
If you are doing wall loading then the T1D bass panels would face forwards and you will position them a bit ahead of the IIIa to get better time alignment.
OK panels are all in and ready to hook up to the amps. Just need to know which terminal should be used for correct phasing. Would the outside wire be plus or inside? Does it make a difference as long as all are the same? I know the tweeters are correct as the factory gave me instructions on them as to hookup, but not sure about the bass and mids. I am going to initially hook up the IIIa's as if they were stand alone speakers until I move. So that begs the question of crossover points. What would the advisable crossover points remembering that I have foil for the mids. This will give me a chance to break them in also. Thanks In advance!
5A fuses on the ribbons is like no fuses at all. If you want to use fuses, go for the ones with solder tags. Do not use the original fuse holders. Do not use slow blow fuses.
Edits: 12/26/14
P.S. Roger I am using a cryo'ed silver LN2 Acme fuse holder.
Roger, Actually I am using 2.5A fuses on the tweeters, and I only blew them once when I forgot to turn off the amps when I was changing something. I think it was when I installed the new X-Over. Not sure. Other than that I never had any issues with fuses blowing. I do use a fast blow fuse. I do not use the original fuse holders. I use a high quality in line fuse holder. I will try to figure out where I purchased them, and let you know. I do recall talking about it here, and this is what was recommended at the time. I will search back to see what I find. Do you use fuses? What would you recommend for the mids? The 20's use a 5A fuse on the mids. I saw an actual picture of the original fuse holder in place. I should get one of the panels back soon. I expect to hear form Sheila the first of next week. Can't wait to see it and hear it. I will have to wait until the other comes back though and that will probably be a week or two into January, unfortunately. She did use the foil you recommended. Should be nice. It looks like the new apartment will not be finished until at least Feb. 1st, so I will most likely have them in the same place when they arrive back. I am not going to change speaker placement until I get them in the new place and new room. It does not make sense to spend the time tweaking them when I am going to move in a few weeks and then have to do it all over again. I would rather spend the time elsewhere as time is a precious commodity to me as I am sure it is to others. Again hope everyone has a Happy New Year!
I have some great news from Magnepan. They have agreed to rebuild my IIIa panels with foil using the foil that Roger recommended. I was really happy to hear the good news when Sheila called me. Magnepan is such a great organization, and their techs are awesome. What company would agree to modify their factory specs for a panel that will be placed in a custom built frame, and charge just normal rebuild prices? I don't think there are many companies that would do that. Maggie also approaches this with the utmost respect for their users. The foil is the same as used in the 20 series mids according to what Sheila told Roger. I can't wait to get them back, plus they will have all new mylar and anything else they need including new bass wire. I will keep you all posted on their progress and what they sound like when they return. I say they as I will be sending in the other panel soon so that I will have a matching pair. We also discussed the possibility of a foil bass of some sort, but Sheila thought that it just would not work with these and had no suggestions to pursue. But we did talk about it, and she seemed open to any other ideas. I am very impressed with Magnepan as a company, and of course, their speakers. As I mentioned in a previous post, I want to keep these speakers as three way speakers that are not dependent on others for completion. Just in case I want to sell them in the future and upgrade. That was always part of my intensions in the beginning. That does not mean I won't use them with my Tympani's. It is all part of a process of growth and learning for me as well, but is the primary reason I don't want to mod the bass to the extent that I cannot sell them as a three way complete speaker. Thanks again to all for the guidance.
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