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In Reply to: RE: Tympani 1-D, IIIa tweeter and custom foil mids using DCX2496 posted by Satie on November 28, 2014 at 15:58:10
Satie, right now I know that positions are less than optimal due to the size of the room and use. As I mentioned, after I move that will change. I am moving into a much larger space with a much better listening area. It will serve dual purpose, and we have not decided how that will work yet, but I will have more flexibility. I understand now what you mean by time alignment in reference to speaker placement. I also understand that this is one of the advantages of the Maggies, that ability. Move them a tad and presto! Much better or maybe much worse. :) What about electronic time alignment? i.e., delay, eq, etc. or even as I mentioned the Dirac Live? Would this compensate for placement given room limitations? Thanks for the crossover suggestions. I will try to get a picture posted somehow, and you will see the present constraints. I am quite aware that it is far from the best setup.
Follow Ups:
Yes, the electronic time alignment will fix the placement issues regarding that. Your Behringer can do it as well as fix room EQ issues with its parametric filters. The Dirac live does that in automatic fashion.
The directions I gave you are to achieve time alignment. The Behringer manual will have a section about the issue of delays and time alignment and there used to be a tutorial on the Behringer website.
It is important when using first order slopes that the bass panels be turned to be the same distance from the listening seat. You can take a measuring tape and secure it at one end to the center of the back rest of your seat with a safety pin and use that as the focal point for a first go measuring distances to the drivers.
Satie, I have uploaded a picture of the front view. That is the best I have at present. You will see the Oak speakers, and on each side out of view are the Tympani bass panels. The center speaker on top is barely audible at present. I can easily take it out of the spectrum when listening to music. i use it primarily for movies.I believe you can get an idea of the problems with furniture. As I said it is far from ideal, as there is a lot of furniture blocking the bass panels especially on the left side. There is a couch/day bed on that side and a custom built stand. A table is on the right side. Again when we move that is all going to change. The panels are however, about equidistant from the listening seat. The listening seat is quite portable as i am in a wheelchair. :) So I can easily move a bit forward backwards left right, to get to the best position. As to the placement of the tweeter/mid panels, to review, I am going to move the speakers left to right (again when we move), putting the tweeter between the bass panels and the mids. So it would be T 1-D bass/bass, then tweeter, then iiia bass, finally mid towards the center. Is that the ideal positioning? In the interim I will familiarize myself with the DCX2496 time alignment configuration and e.q. All will be on hold once we ship the IIIa panel back to Magnepan next week. I am anxiously looking forward to the results of their assessment. Shirley said she was open to redoing it with foil, and that we could discuss it once she had it in house. I love the attitude Magnepan has towards it's users. They are so warm and friendly and a joy to work with. Thanks again.
The I guess what you would be doing while the III bass panels are out at magnepan is using the T ID tweeter for the top end. In the original T-ID the XO was 1st order at 1khz. The tweeter is not as good as the ribbon by any stretch, So I am thinking that you can move your IIIa tweeter to the side of the T-1D tweeter panel by screwing the hinges into it the same way the ribbons are hooked up to your frame. Then you can cross the ribbon tweeter over at 4-5khz. The T-1D tweeter would then be used as a midrange. You can experiment a little to see if the T-1D tweeter can handle a wee bit more lower freq duties.
If the T-1D tweeter panel is not functional then you can still run the bass panels up to 2.5khz and use the ribbons above that. The mids will be thicker than you might want but still fairly good.
Satie, I think that your second suggestion makes more sense given my time constraints with business and moving. I would temporarily use the 1-D panels as mid/bass crossing them over as you suggest. So essentially I would have a two way active crossover, and would I still use a first order filter at 2.5k? This is just a temporary fix anyway, and I would still be able to listen to the Maggies while the bass is being repaired on the IIIa. Thanks for the idea. We are working on the new room configuration and after some thought, hope to have just the speakers, stereo equipment, and maybe another TV hanging from the wall in that room, with sparsely placed furniture. I always have my seat with me ha ha, so I can move anywhere. There are some pluses to being in a wheelchair. I have a very comfortable reclining chair that can me moved less than an inch at a time with just the tap of a joystick. :)
Yes you can do it that way, just keep the ribbon protected with the shelf setting on the DCX - you can play with the specific freq of the shelf to see how far down you can put it without jeopardizing the tweeter's performance. You should mount the ribbon with a separate support so that it is not in contact with the bass panels.
Satie you mentioned a tutorial on the DCX2496 on time alignment used to be available on the Behringer site. I scoured the site and found nothing, so I guess it is no longer available at least on their site. I was wondering if you or anyone else has their tutorial. I really like this unit and can see the potential but the docs and support could use some improvement. There must be something available somewhere given the popularity of this crossover.
The tutorial was obviously written by someone who is not a native english speaker. So not a great loss and probably why it was taken off.
I don't know of another tutorial for the DCX. Rane (manuals for crossovers), Wikipaedia and Linkwitz have discussions of time alignment without reference to the DCX. I read the manual for the DCX and found that it was understandable. So I can offer my interpretation of the manual if you find some part difficult or unclear. At least it isn't as dry as some software manuals. Some of those require alcohol to wet them.
Satie I re-read the manual and studied it some more. It is a bit cryptic, but as I study it further it is understandable. You mentioned an HP shelving filter option, crossed over at 800hz for the tweeter. Would that be done that in the EQ section? I am sending the IIIa panel in today or tomorrow and I talked with Sheila about the possibility of putting foil on for the mids. She said they would consider it, as i mentioned before but needs to know what foil I would like on there. Would it be best to use the foil Roger was talking about, in your opinion, and if so, do you know specifically what it is, or perhaps Roger could chime in here? Or would it be best to just have them returned to original? Yes I would love to use Neo-8's and maybe that might be in the future, but if foil would be better than the original wire and Magnepan is willing to do it, would not that be the best way to go for now?
Computerman,
The foil is 0.0005"x0.1", same cross section as a round wire AWG32. It is what they use in the 20-series mid drivers, Sheila said.
Thanks Roger. Do you think these will sound better using that foil than they would with the original wire? The foil I used initially had a great sound but I had nothing to compare it to as these were pretty delaminated when I purchased them .I think it is great that Magnepan would even consider doing this.
I would not expect a huge difference going from round wire to a flat one. In your case it would be a step in the "better" direction as the foil you already have is too massive.
What will you do with the bass wiring? I dislike the combined bass-mid concept. The separate bass, mid and tweeters that you find in the larger models are more to my liking. The Tympani ID bass drivers are probably better than the bass of the IIIa and matches the mid of the IIIa better. The IIIa basses are double mass the ID basses. Maybe you can have Magnepan build separate midrange drivers? It would be possible to do that if you can sacrifice your IIIa basses. Magnepan will probably not do that...
Maybe you can let Magnepan re-wire the bass with foil, 0.001"x0.1", two loops will give you about 4 ohm in parallel. It would make the bass more suited for filling in the gap between to Tympani basses and the midrange driver. It will not work as a IIIa true bass driver with that foil. Your ribbon tweeter are very far from the midrange driver, not very good if you want to have good imaging.
Roger, to reiterate so that I am clear with what you have proposed. You suggest perhaps having Magnepan use the entire surface of the IIIa panel for midrange if they will do it and that they probably would not. That is a very interesting idea. It really makes me wonder what the sound would be like.
I probably will not go that route because I want the option of using the IIIa's by themselves. Most likely I will not do that, but I do want that option. Plus if I ever decide to replace these, I would have a full range speaker unit to sell. I could also try Satie's suggestion of using the bass of the IIIa along with the Tympani bass. that sounds like a possibility. I am of course, at present using the Tympani bass alone, I totally agree that the Tympani excels in bass compared to the IIIa. I have compared them in the past.
No, not the entire bass+mid as a mid!
I mean creating a four-way system. Tympani basses below circa 120 Hz, modified IIIa basses covering 120-500 Hz, IIIa mid 500-3000 Hz and finally the ribbon tweeter.
I see less potential of using the IIIa bass as it is originally, the Tympani basses are better in covering that frequency spectrum. Remember the Tympani basses is about half the moving mass of the IIIa basses. Maybe, I should make a drawing to give you a clearer view? You can send me an E-Mail, so that I can provide you with a drawing.
Roger, I received your email, and drawing and thanks for all the great information on the Maggies. To answer your questions, first, the IIIa's are in frames similar to the ones that Peter Gunn built. We studied them and if my memory serves me well we actually consulted him on the forums. We copied what we considered at the time to be a good design.
As to the tweeters, I am not sure of the output on those i will check with Shirley when I speak with her once she gets the IIIa panel in that I shipped yesterday. I do not recall resistors. I don't dare take a measurement as I broke my leg a couple of weeks ago and have to be careful. She has a record of everything. I spoke with her recently to get an update on my Tympani's as to rebuild information. They keep a complete record of all of this. She informed me that they had all been rebuilt and gave me the specific dates and glues used. I had one panel with a couple of loose wires, which was rebuilt in 1997, and they used milloxane on that. I re-glued it with 3M NF30 to bring it up to date. It was in very good shape and did not need much repair, but since I had the cover off I did the whole panel with 30NF. There are two others that were done with milloxane in 2004 and so far they are in excellent shape. I think she said that was the last year they used miloxane and she also indicated that it was an excellent glue but not as UV resistant as the 30NF and more prone to delamination. The T 1-D tweeters and one other panel were rebuilt using 3M 30NF in 2007. All panels are in great shape. The IIIa tweeters are essentially new as they were swapped out.
I sent the IIIa panel in for rebuild only. I am sending the other one in eventually as well. Maybe as soon as I hear what the cost to rebuild the present one will be. Might even be this month.
As to the placement of the tweeter, that is hinged so it could be easily moved to the other side to be between the mid and the T 1-D's. i was thinking of swapping the whole speaker side to side, placing the tweeter next to the T 1-D's which would accomplish the same thing as switching the sides of the tweeter. So they would be arranged, from the outside to the inside, T 1-D bass/bass, tweeter, IIIa mid then bass of IIIa on the very inside edge. I am not sure that is ideal, but it would put the tweeter and mid next to the T 1-D's. The tweeter can be put anywhere as again it is just hinged to the IIIa frame. It could even be detached and somehow attached to the T 1-D. Just throwing that out there. I know Satie proposed something like that.
You have given me a lot to think of. As you mentioned I don't think Magnepan will wire the bass panel as you suggest. They have agreed at least tentatively to use foil for the mids. But I do think it would be a stretch to ask them to wire the bass as you suggest. I am not sure I would want them to, and the reason is that if I keep them as a three way, then if I ever want to sell them separately I could.
In your picture you sent me, you are stating that the bass panel would all be wired with 0.001"x0.1" foil? How would that work as a separate speaker were I to separate them? Would it work as a separate three way similar to the original? Or will it be too exotic to respond in that way? Just curious for reasons stated. I might even ask Magnepan just to see if they would if it would work as a completely separate speaker in the end. I will probably never sell these things, but I would like to have that option, should I want to upgrade.
My plan is to eventually work some Neo-8's into the picture. I am not sure how soon that can take place, but it is in my mind to do so. Would that, in your opinion, be the best for mids that are available within reason?
Thanks for the great ideas and putting so much time and thought into this.
I think you would want to keep the IIIa in sellable condition, not converted into big midrange and little midrange. If you want a separate midrange, you can get two pairs of the on wall MMGW's and stack them in a frame - or just one pair. And build a frame for them with the tweeter. MCI may work as well for much more money.
Then there are the RD50 from BG - probably do you well at $1100, but are dynamically limited.
A line of Neo8 will provide you with amazing dynamics, unlimited power and precision, and can let you operate the tweeter from a higher up XO point where it distorts much less. That pleasure is $1200 for a line of 6, or 1600 for the ideal line of 8. And you don't have to buy the entire line at once. You can add to it over time till you reach the ideal length for your purposes. With EQ and limiting midbass duties you can use as few as 4 per channel to start. A line of Neo8s or Neo 10 can be crossed over at a lower point, but these are slightly slower and more expensive drivers and they do not play as well at the top range. You want to XO to Neo8S line no higher than 4 khz up to 6khz if you don't mind a marginal loss of resolution relative to the ribbon, and you would probably need to XO the Neo10 at 2-2.5 khz since their dispersion already drops off <2khz.
Ok so for now we I will stay with foil for the mids, and think about how soon I can update the mids to Neo-8's. When that time comes, we will talk about this part again I hope. I do appreciate all the great comments that everyone has posted. I certainly have leaned a lot and will continue to participate in the forums to see what i can contribute. I hope some have benefited from our discussion as much as I have. It is always a pleasure. I wish all a very happy holiday. I will be sending the other panel back soon. As soon as I hear form Sheila, and have an idea of cost it will be on its way. I am anxiously awaiting the results of the rebuild. I do have one question, if I were to use the bass of the IIIa as some have suggested, how would I add it to the crossover and at what point/slope would you recommend? The DCX2496 is only a three way crossover, so would I have to go to a passive crossover for that?
I believe the 3.x models have a lot of IMD issues because of deep bass on the bass panel shaking the other "drivers". So IF your bass amp/s can handle a load below 4 ohms then I would run the IIIa bass panel in parallel with the T -1D bass panels BUT put a 1st order speaker level XO between them at somewhere between 100 and 150 hz. Just one BIG GAUGE coil to low pass the T-1D and one film cap to high pass the IIIa bass. You will probably end up having to put in a resistor on the IIIa bass panel to tone it down relative to the T-1D since it is 4 ohms and the T-1D is 8. very inefficientThe other (better) option is to get a medium powered amp for the IIIa bass panel and take the bass output from the DCX and split it at line level with a 1st order PLLXO at the same freq as above. You will need to have a volume control in the IIIa bass amp or add one in. You can also daisy chain the bass with another DCX2496 (you will need to add delay to the mid and tweeter channels to compensate for the second DCX's deay. You can also get a Rane or Ashly 2 way XO on the DCX bass output. They are very good in bass performance. And you can do a 4th order XO in the bass with no harm so long as you time align the 3 bass panels per side. They are quite cheap on the used market, and don't introduce a delay unless you dial in the Rane to have a delay.
You really don't want to have the output of 3 bass panels stretched over 5 feet without time aligning the panels or at least crossing them over to put the far away panel's output outside the imaging freq range.
Edits: 12/06/14
Roger, I understand what you are saying. To update you on my amplification currently, I have, a Crest CC5500 which outputs 1800 watts per side into 4 ohms, which is being used for the Tympani 1-D's (which incidentally are 4 ohms, not sure where you got the 8 ohm spec, correct me if I am wrong, but I believe they measured 4 ohms with a multimeter, plus the manual states 4 ohms). I have a Rotel 7 channel amp which outputs 200 watts into 4 ohms, of which I am only using three channels, one for my center MGCC1 speaker which I take out of the picture when listening to stereo music., and two channels for the mids. That leaves 4 outputs to power something. The third amp I am presently using is an older ADA PF-200, which outputs approx. 150-200 watts into 4 ohms, which is being used for the tweeters. My thoughts on what you have proposed, is to obtain a MiniDSP unit of some configuration, maybe even a 4dx10, add that into the mix for further active crossover control. Use the Rotel for the tweeters as it is probably a better amp than the PF-200, although ADA may argue that point. Use the ADA PF-200 for the IIIa bass panels. I understand what you are saying about all being on one panel for the mids/bass of the IIIa. I think that was a poor design move by Magnepan. What do you think of this proposal? That would allow me to use active crossovers and I would love to get familiar with the MiniDSP and the measuring software. I have a Behringer EMC8000 mic and a mixer so that I can connect it, plus I understand measurements can be taken attaching it to the DCX2496 as Satie was referring to earlier.
Sorry, ancient memory, IIRC it was the 1 U that was 8 ohms????
Sounds like a good alternative. But if you like the Behringer then the add on Rane or Ashly XO is peanuts off of Craigslist.
Either of your power amp ideas is good. Should do fine. I just would avoid having a multichannel amp do both bass and mids or tweeters, particularly tweeters. So having the ADA on the IIIa bass seems the better idea.
I wish I could listen to something like the Behringer, but the sound it produces rubs me the wrong way. It is really hard to do decent digital, not to speak of good digital. Keeps me away from miniDSP and even TaCT and DEQX. Restored vintage 82 Japanese TT/cart outdoes all the digital I have heard. My DAC outdid an EAD 7000 that had been tweaked out. And I thought it was pretty good. The PS Audio DSD was a revelation to me, I didn't think we would get there before my ears give out from old age. We are doing the PS Audio DSD on my setup next week after the new upgraded firmware that got so much buzz. Hopefully that will open up the possibility of a digital future for me other than as second choice just to access newer recordings. I would so much like to EQ and time align everything digitally.
Satie, have you ever tried the DEQX, or any other form of digital time alignment? Have you used REW at all? Just curious what your thoughts are on it and your experience.
I also own a computer based crossover program that comes with Pure Vinyl. i think we discussed this some time ago, and they claimed to have improved it. It is Mac driven, and I have a couple of Macs to play with, and can devote one to a crossover if I so desired. Their website is http://www.channld.com/purevinyl/ Also have you tried anything like the DiracLive? Have you ever tried the auto align method of the DCX2496? Do you think it is worth doing? thanks in advance..lots of questions.
The Behringer lasted less than a week in my use. It was returned and I was disappointed that even toning down the FR with an overall downward slope EQ it was not listenable at all.
I tried M audio multichannel USB interface (they called it an external sound card then) + free download XO software that was slightly informative on what you can do. Could not stand the sound, did not bother with it again, 24/48 mya$$. Went back on the 3rd day. Headphones directly off my laptop soundcard sounded better.
I used REW to measure the speaker drivers but it did not teach me anything I had not measured before on that count, but time issues were a bit more interesting. However, I found that with the LR4 XO that Marchand talked me into there was no choice but to time align all the panels - before I actually did the REW measurements.
I learned that fine tuning the XO for 1st order and 2nd order PLLXO I was better off listening to the warble tones +meter rather than doing sweeps and noise bursts. I could then relate the measurements immediately to what I was hearing. I didn't depart from equidistant placement during any of the XO experimentation till this year.
I have not heard of the Pure Vinyl XO other than from you, I have not tried DEQX or TaCT. When I had the Behringer I did not try the autoalign because its sound made me distrust it by then.
I compared EQ with my White Instruments passive to EQ on the Behringer and was absolutely stunned by how much more transparent the analog passive was. Just not playing the same game.
The issue is that mediocre digital had become unbearable at real live volumes with the Neo8 it reveals everything whether you EQ it to take the edge off or leave it free with its little bump at 6-8 khz. It makes obvious such things as the break-in of a cap or a new solder joint.
I know that folks are not as sensitive as I am to digititis and I know a thick sounding midrange and lower treble can hide it. Like my setup, my friend's Focal Nova Utopia took apart the supposedly good ADC/DAC of the QOL device, I could not get past the obvious digital artifacts to try and evaluate what the device did. Most digital I have come across sounds like the RatShack "gold" interconnects. In PCM you could not get anything passable below $2k besides the Monarchy tube DACs. I got my lead brick 1 bit Sony CD player that was bearable but the Musical Fidelity DAC/Pre made it actually enjoyable on some recordings and had decent imaging texture and tone etc. I could even run it directly without a tube line stage to take the edge off. But that was a sleeper product that had flopped on its single production run since its connections were out of date before it hit the market. It was designed to be a $5k product but was just closed out at $3k for the one production run. I bought it used for bubkes.
You can get good and perhaps even great PCM digital (being less cynical about reviewers) if you do a discrete resistor ring or ladder DAC if you have a good clock and very clean PS on it. Turns out that making those costs a bucket load of money and has only recently become doable at anything resembling a reasonable cost with the drop in the prices of low jitter clocks (by a factor of more than 10). Even el cheapo DSD has fewer digititis artifacts than 2 or 3 grand PCM. It is at least listenable without irritation.
About all I can say is WOW..you have either "golden ears" or I have been listening to so much noise, i cannot tell the difference. Most likely the former is true as I am getting older and I do have the dreaded tinnitus. I was using a TDM 3-way active X-over, and the DCX made quite an improvement over that. That did not surprise me as I am not sure of the quality of the TDM. I guess the thing for me to do in the future, is to try some good passive implementations, and set up an A/B test. I would also like to try the Pure Vinyl route knowing the quality of their recording software, which i have found is phenomenal.. Using it gave me the best of both worlds. Vinyl on digital. I believe I got a better result from recording vinyl to the computer using their software for playback, than "pure vinyl" alone. They also recommend the Impact Twin as a DAC/DAW and that to beat it would cost near $5000. I also use some custom optimized cables to attach my turn table to the Twin. I just talked to them as my present Twin bit the bullet, and I was hoping to improve on it, but they claim that they found through their testing, that the Twin is the best under 5 grand. Hard to believe, but you know sometimes people get it right. It can now be picked up for a measly $229 on Amazon. If you had the extra money, it might be worth trying. Maybe a test and return if you don't like it kind of thing? I wonder what others think about digital processing. After I move and get settled in, get the new room set up, and all the recording system set up etc, I am definitely going to give a passive implication a test, if I can afford it. I can build them if I have the specs of the caps, etc. I was also thinking about investing in a MiniDSP 2x4 or similar unit (100 bucks or so) to use for the IIIa base addition. What do you think about that?
Also as I do not have the Neo-8's (yet) I can only imagine. That one is definitely on my list.
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.
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.
.
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.
computerman ,
Try this link , I think I have it right this time . . .
This Guy describes using the DCX auto time alignment
Thank you very much!! it is very helpful as any info on this unit is hard to find that is not cryptic.
computerman ,
Here's another link where the same gentleman does a shoot out
of Active crossovers . . . that is Listening Tests . . . very subjective , but it will give You some insight into what He was hearing
Yes, ID is 4 ohm. IIIB too. IC and IIIA are 8 ohm. I think the bass of the MG-IIIs is a bit "in the way" of the rest while using Tympani basses.
Roger, Actually I am not sure why but the bass on the IIIa measured 4 ohm. hmmm...Of course they are being rebuilt so I guess that will bring them back to 8ohm? Is there any way they can be wired for 4 ohm if I ask Sheila when she calls. They have the one panel at the factory now for rebuild. As soon as I have a price and specifics on it, I am sending the other panel in. Anxiously waiting her call and hoping they agree with the foil mid as you suggested. I gave then the specs you suggested as well for the foil.
The MG-IIIa have 4 ohm basses. No need to worry!
I think he is aware of the issue, but if it is focused with the Tympani bass panels being setup with equidistant centers to the IIIa bass panel then it should work better and integration would be better with the mid being closer to the midwoofer and the Tympani doing the real bass.
Roger how do I send you my email address without advertising it here? I don't want to end up with a bunch of spam. Thanks that would be a great idea if you could send a drawing.
I don't have anything to add to Roger and Stephen's comments on the foil. They know what they are doing.
First, the DCX's PC control software is far easier to use than the tiny display on the DCX itself. So download and install it first if you have not done wo already.
http://www.behringer.com/EN/Products/DCX2496.aspx
"editor software 1.16a" in the middlle of the apps line a few pagedowns on the documents tab
you can then adjust the basic configuration and then the XO and then the shelf in the eq section for the output channels (12 db low shelf, -15 db and 300hz - which gives you a -3db point of 800hz for the shelf) then you go to the delay section of the output channels and put in the delay distance you need - in the units you selected to work in - probably ft and deg F. I would not turn on the temp adjustment feature.
The Time delay adjustments are from the difference in distances between the tweeter and listening spot and the midbass panel to the listening spot. Put up a mic stand to attach the measuring tape end. And wiegh its base down so it does not move when you stretch the tape.
If you have the measurement mic, you can use the automated delay and phase adjustment the manual covers in section 4.2.2.
Satie, I have been using the software and purchased a USB to RS-232 adapter and it works much better than trying to read and set the front panel.. Thanks for the specifics on the filter. I will be sure to implement that as soon as I can free up some time.
computerman ,
Here is a link to a gentleman who uses a DCX2496 to time align speakers . . . it seems fairly straight forward .
http://redspade-audio.blogspot.com/2010/12/time-alignment-with-behringer-dcx.htm
I have re-wired 2 MGIs with foil , and I use them for the mid-range . . . I used foil from Magnepan that is 0.0005"x0.1" . When I talked to Sheila , I told her what size of foil I wanted , and what length I needed . . . I also ordered a Quart container of the milloxane , that way I have enough to do other experiments in the future .
The MGI re-wired with foil , measured 3.2 ohms .
P.S. Stephen I tried that link and it is no longer active, but thanks for the thought.
computerman ,
Here is a link to a gentleman who uses a DCX2496 to time align speakers . . . it seems fairly straight forward .
http://redspade-audio.blogspot.com/2010/12/time-alignment-with-behringer-dcx.htm
I have re-wired 2 MGIs with foil , and I use them for the mid-range . . . I used foil from Magnepan that is 0.0005"x0.1" . When I talked to Sheila , I told her what size of foil I wanted , and what length I needed . . . I also ordered a Quart container of the milloxane , that way I have enough to do other experiments in the future .
Stephen, thanks for the link. You might want to think about using 3M 30NF as that has replaced Miloxane. It is supposed to be much better and is the material that Magnepan is presently using. I spoke recently with Shiela when I had to re-glue one of my Tympani's. It was rebuilt at the factory in 1996 I believe, and some of the wires were delaminated, but not badly. It was a simple fix to re-glue them with the 30NF. Sheila stated that the 30NF is much better than the Miloxane, but that the Miloxane is still a good glue, but it should no longer be used.
Hard to understand how the larger Magnepan speakers can really do their thing in such suboptimal set-ups....Seems so many try to stick 100 lbs of speaker in a 50 lb room....
try it! you know you want to!
Perhaps you should read the posts more carefully
Isn't that what i stated? no reason to rub it in. Unfortunately some of us do not have the privilege to avail ourselves of separate listening rooms. We have to make do with what we have.
Well, if you can't change the room, you could change the speaker to something better suited to the venue you do have....
Not trying to rub anything in, just trying to be realistic...
try it! you know you want to!
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