Here is a link that might answer some of your questions. Scroll down towards the bottom of the page for biamp info:
I wouldn't bypass the fuse/fuses in any speaker.Directly soldering the fuse will most likely ruin the fuse. Onkyo does not give a true 4 ohm power rating that I can find.It would have to say something like this,200 watts per channel into 4 ohms with all channels driven simultaneously.It doesn't even give a two channel rating at 20 to 20khz into 4 ohms.Who knows what the power is at 4 ohms. People on the net claim they are bi-amping. The fuse removal plus bi-amping was in this link provided by Mofimadness link.>>[http://www.integracoustics.com/MUG/MUG/tweaks/paco/]
..Both the woofer and tweeter sections are 4 ohms.
..Yes, you can hook up full range signals to the woofer and tweeter input terminals (the tweeter terminals are those connected by the jumper). This will utilize the passive crossover, which I don't consider true biamping.
..If you want to biamp using an external electronic crossover you need to perform surgery on the speakers to bypass the internal passive crossovers. I don't recommend biamping these speakers because the characteristics of the internal passive crossover are a bit unusual, and hard to duplicate with an electronic crossover.
My reason for bi amping wasnt for using an external cross over to clean up the signal, it was for gaining the additional power from the 2nd channel. The above poster is correct, I cant find real world specs on the Onkyo's 4 ohm rating, but there is definitely more power in 4ohm, and it does kick the amplifier down. The Onkyo has the ability to Bi Amp using the rear 7.1 channels and outputs the same signal as the mains. Therefore you would gain double the power. I realize these arent mono channels, but most flagship receivers do ouput very close to there rated channels on the bench, even with all channels drivern. I cant say for sure I'm getting around 200 watts from the fronts and rears in 4 ohm, but it would have to be greater then the 145 watts @8ohm. I do know that this Onkyo receiver crushes my Magnepan mmgs in the 4 ohm setting. I used a Sony receiver from a few years back, and it couldnt even come near the volume the Onkyo delivered. This setup is for home theater, so I want to make sure I can handle the 1.6's with this receiver, but I think I'll be OK. Specially if the Magnepan can be biamped and the Onkyo works as it states it does. Again, I do know for sure the receiver drops down to 4 ohms, even in bi amp mode. It has a bridging mode that delivers 220 watts in 8 ohms to both front channels, but you cant go under 8 ohms, so I wont use that setting on these speakers. Being that its home theater, I'll likely cross the 1.6's over between 60-80HZ
I'll do some diggin around for some bench tests on the Onkyo 906.
The new receivers don't have to follow the old FTC rules for audio gear.The more channels you drive,the less power is typical.8 ohms is the standard for home theater receivers and systems.That is why a lot of them have a external or internal switch for 4 ohms.A lot of them put a 4 ohm resister in series in the 4 ohm setting.That why a lot of people use power amps that will drive a 4 ohm speaker without the need of the resistor to take the load off of the amp.Even Onkyo's flagship Integra receiver can't give 4 ohms into all the channels.The 906 only consumes about 1152 watts total.100 of that is probably getting wasted as heat,like power amps do.By what the web says you can bi-amp the speakers.The only way to see if it does better,is by trying it.Here is a link to what is happening with a lot of receivers driving more channels.The power supply in most can't give full power at once into a lot of channels.Some rare ones do.Home Theater magazines test give you a good idea on the Onkyo 807's power.30 watts a channel times seven.Link>>[http://www.hometheatermag.com/receivers/onkyo_tx-nr807_av_receiver/index4.html]
I forgot to say,you could see they got a higher output at 4 ohms,but they only did two channels.Driving more channels into
4ohms might kick in the protection like the manual says in a round about way over long periods of time.The Maggies don't tell you when you split them if the highs are 8 ohms,and the lows are 8 ohms.They may be a little different than 8 ohms each half,but still look like they combine to 4 ohms.They wouldn't be 4 ohms each half,(that would make them 2 ohm speakers).
The more channels you drive,the less power is typical.8 ohms is the standard for home theater receivers and systems.That is why a lot of them have a external or internal switch for 4 ohms.A lot of them put a 4 ohm resister in series in the 4 ohm setting.Wow, that really s**ks!!
The Maggies don't tell you when you split them if the highs are 8 ohms,and the lows are 8 ohms.They may be a little different than 8 ohms each half,but still look like they combine to 4 ohms.They wouldn't be 4 ohms each half,(that would make them 2 ohm speakers).I don't think that is true, and ElDartford's earlier comment about each section being 4 ohms is correct. Consider the non-biwired, non-biamped situation. At low frequencies, the speaker's crossover causes the high frequency section of the speaker to essentially not be seen by the amplifier (i.e., to be a very high impedance). At high frequencies, the speaker's crossover causes the low frequency section of the speaker to essentially not be seen by the amplifier (i.e., to be a very high impedance). So at any given frequency (apart from the crossover region) the amplifier sees the impedance of only one section of the speaker, not both sections in parallel.
Figure 1 of Stereophile's measurements of the MG1.6/QR shows its impedance characteristics. 4 ohms at low frequencies, 4 ohms at high frequencies, and a rise to over 18 ohms in the crossover region.
When I had the 1.6 I made it a point to passively, vertically biamp them. It was a nice improvement. I am not into DIY or modding speakers, so this was a way to juice the performance. On an MMG I would suspect you will hear differences, of course mainly in the quality of the mids and highs. You should detect more "air", deeper soundstage and better clarity. Not in "boatloads", but maybe in "spades".
Some state that passive biamping is of little effect, while others say it's very worthwhile. There was to my ear a very noticeable change to the speaker's performance in my experience. Having used passive speakers with external Xovers (reviewed the Legacy Audio Helix), I can see where a modded Maggie would be considered even more enhanced.
Over time I experimented with more stout amplification and bi-wiring. I found that having a more robust amp and bi-wiring can yield even better results than using lesser amps and biamping. You owe it to yourself to secure possibly an older, well respected amp with some braun (i.e. doubles down into 4 Ohms, and maybe at least 150wpc at 8 Ohms) and see what you think. My guess is that you would be very surprised at the difference in sound of such an amp bi-wired versus the four channels of a receiver. :)
Are you thinking the 906 is driving 696 sq in MMG's fine so I'll use another 2 channels of amplification to drive the extra 539 sq in's of the 1.6's?
Personally I'd keep the MMG's, they're working fine correct, and save up some money to upgrade the amp first then the preamp. My reasoning is the MMG's are very good in their own right and can handle upgrades of the amp/preamp in your system before you "upgrade" to the 1.6's.
I would upgrade to a better quality amp first and use the preamp section of the 906. When you save enough again you can upgrade to a higher quality preamp at which time you will experience how good the MMG's actually are then decided if the 1.6's are necessary!!
I say this because I had a Onkyo 905 in a HT system with 1.6's driven by an external 250 watt @ 8ohm amp it worked for HT but the quality of sound for 2 channel wasn't very good. Bottom line the preamp section of the Onkyo's are the weak link for 2 channel.
Caps in the stock 1.6 are Solon and can easily be bettered, but at a price. When going to an aircore inductor, you need to keep in mind that the issued inductor is 16 ga. of 0.4 ohms (DCR) To duplicate this inductor in an aircore requires 14 or 13 ga. wire, and of course, a bunch more of it! There are several online calculators, if you want to run some simulations.
Eldartford is correct. Unless you've got a jackhammer handy, you are into an external x-over.
Cap choice is very subjective. I'd be curious to know what caps 'Eld used in his mod. I'm about to pull the trigger on ClaritySA.
Don't forget that the wiring in the panel is pretty cheesy, too. A proper, fully detailed job can replace a bunch of wire and connections, get rid of the fuse and go to binding posts, if you want to be rid of the banana connectors. Go ahead and peek thru the crossover cover cloth on the backside. Bring a strong flashlight.
Go to *Magnepan Users Group* for a good afternoons read.
Almarg,I shouldn't have put 8 ohms each halve without knowing the speakers measurements.Some speakers have crossovers with odd impedance characteristics.It would be nice if the companies gave more spec's with the bi-amp option.Amplifier companies could give us a lot more spec's too. After looking at the chart,I don't why some people act like they're(Maggie's) a nightmare to drive.They are inefficient,and 4 ohm speakers,but look nice and stable(nothing dropping down 1 to 2 ohms or something like that).Magnepan link>>[http://www.magnepan.com/faq#power]
Maggies, the 1.6s in particular are indeed, not a 'bad' load. People that call them such look at impedance and sensitivity without looking at the 3rd leg of load evaluation. ANY amp with reasonable current into 4 ohms will be able to drive 'em. Some, of course, better than others. YMMV?
Phase Angle of these panels is moderate from hi to low.
Please look (if you haven't already!) at the link provided by AlMarg to the Stereophile measured data panel. This clearly shows the phase data. If you are curious, write back and I'll BRIEFLY go over the math. It is very simple and will be an eye opener. All you need is a scientific calculator, either handheld or the free one with Windows or Mac. No rocket science here, either.
The DCR of EACH driver of the 1.6 is 4.5ohms, +-0.1 ohm. This includes the lopass inductor of 0.4ohms.
As a sidenote, reviews seem to encourage the low impedance as bad load philosophy. There is simply not enough measured data for people to think otherwise. The only source of real, measured data is Stereophile which has been publishing this data for years. I don't know how long! Speakers which have both a low impedance dip AND a large phase angle are generally identified as 'bad' loads. The 1.6s don't.
And, if that isn't enough, I don't see the 0.1uf 'bypass' cap in my crossovers. I peeked, using a strong flashlight and I don't see 'em. Both schematics I have show 4 hipass caps totaling 22uf. Both my speakers have 21.9uf.
I was told by someone who should know if anyone knows that the 1.6 dual inputs are just there because people kept asking to be able to biwire, but they are not actually separate inputs and internally go to the same place. The 3.6 and above can be actually bi-amped w/active crossover and other configurations, but from what I was told the dual input on the 1.6 is just for those that believe in biwiring.
Lightminer...Whoever told you that had never had the X/O apart!
Magfan...I used Hovland capacitors. There is considerable opinion that Solons are not bad at all, and, as you say, any improvement would come at high cost. I didn't know what kind of capacitors were in the MG1.6 when I ordered parts for the project.
My air core inductors are AWG10, so the DCR is lower than stock. The effect on crossover frequency is insignificant. Crossover frequency is somewhat arbitrary anyway.
The bypass capacitor is really there. It is a small ceramic which you probably can't see through the cloth.
Magfan,Thanks for the offer,but I'll pass on the math part.Years ago I used to change the tweeters and crossovers in a lot of speakers.I did a lot of math back then and used to get a good sized headache.Some did turn out a lot better,after I got the crossovers correct,maybe? Thinking about it gives me another headache.A friend had a pair of Apogee Scintilla'a that were the worst pair of speakers to drive that I've ever seen.They cooked one of his power amps.I think some people tie those to other panel speakers.Another friend has a pair of older Maggies that he now drives(just found out last night) with a Conrad Johnson EL34 tube amp with ease he said.Its his two channel music/home-theater system in his bedroom.He said it is sounding great. Best Regards
Ok, I'll skip the math! Most people don't do numbers well, as you could tell if you could see my checkbook!
However, I DO urge you to google 'Power Factor' and just look at the Wikipedia article. This will give you and others a basic understanding of PF and why phase angle can be an amp killer.
Personally, the 'online calculator' for various things is a lifesaver.
The MMG's are good, but not near the performance I'm used to. Ill continue looking for some 1.6's. If the Onkyo cant swing it, I'll try a crown amp on them. Keep in mind this is mostly for home theater and will be crossed over at 80hz all around. This is just a fun system, so Im not investing in expensive amps. The crowns will work if need be. You guys had some great points I didnt think of. A all around 4ohm magnepan system could indeed be a tough drive for the Onkyo.
Yeah - that is definitely what they said. Don't know how to reconcile. I believe you - perhaps it was added at some point or electrically there is some technical way that both can be true and/or he was speaking in a more general way - certainly the 3.6 and 20.1 are wired very differently when coming in along the 2 separate inputs... Don't know!
Right, that is what we are talking about, no? Who is on first? I was saying that I was told the separate inputs behind the panel don't really do much (and were just there for biwiring) compared to the 3.6 and 20.1 which have totally separate electrical paths if you use the dual inputs, and you were saying the opposite.