View Full Version : Yamaha Z9 set at 6 ohm or 8 ohm for Lsi25
09-07-2009, 11:30 AM
The Lsi25 is 4 ohm speaker. Yamaha Z9 can set for speaker out put at 6 ohm or 8 ohm, what should i set for Yamaha Z9 when it's running Lsi25 ? set at 6 ohm or 8 ohm is better ??? thanks
09-07-2009, 11:32 AM
Neither. You can try it @ 6 ohms, but don't crank it.
09-08-2009, 04:04 AM
Sniper, despite the suggestions in the manuals, the lower impedance setting on a receiver should never be used. This in no way optimizes the amplifier for a speaker rated at a lower impedance, as is sometimes imagined. This setting simply reduces the voltage output that the receiver power supply is capable of, and is a type of fire safety precaution required by U L(Underwriters Laboratory). When the voltage is reduced so is the current(following Ohm's Law, I=E/R) and the power output which results. Tests by Sound&Vision Magazine typically show that the maximum power capability is roughly cut in half when the lower impedance setting is applied. So, although the chance of overheating is reduced, so is the maximum performance capability. This increases the possibility of damaging the speaker when clipping occurs because of the lower maximum power capability.
The amplifier in the Z9 is quite powerful and can power your Lsi25s to very high levels when operating at full capacity. Leave the impedance setting at 8ohms.
The amplifier in the Z9 is quite powerful and can power your Lsi25s to very high levels when operating at full capacity. Leave the impedance setting at 8ohms.And when your receiver goes into protect mode or you blow a tweeter, you can blame this idiot.
You need an amp, plain and simple. Your Yammie can drive them, but not to reference levels. I'd be conservative with the volume for the time being.
09-08-2009, 12:06 PM
+1 to what Face has to say. The Yammi is nice and you have one of their very best, but the LSi25's require much more juice than it can deliver. Get yourself a good Power amp to drive them and you will be quite pleased.
The CW is that most receivers cannot properly drive 4 ohm speakers. Also, receivers that have a "special" setting for 6 ohm speakers are even less likely to be able to drive 4 ohm speakers properly, since they essentially limit the current output in order to avoid overheating and damage to themselves. NAD receivers, which are famously rated for 4 ohms and even 2 ohms, do not have a switch or setting for more difficult loads.
It never ceases to amaze me when people choose a receiver that the manufacturer clearly does not rate for low impedance loads, and still take the advice on various audio forums saying "it's a beast", "it's a monster that weighs over xxlbs!", "your ears will bleed before you hear a hint of distortion or damage!" ... If the manufacturer rated the unit for 4 ohms, then they would have to cover any repair costs from using such speakers under warranty. When the unit is not rated for 4 ohm loads, and you drive a 4 ohm load with the unit, then they can refuse warranty work stating that the unit was not used according to the instructions contained in the product manual. So, everyone is in agreement about this, right?!
Now, to further the discussion somewhat, I've frequently heard people state that the Pioneer Elite SC-XX receivers can drive four ohm loads effectively, yet here is a review that says this Yamaha receiver actually does it better:
... Our measurements are very conservative and it is clear that the 140wpc power rating of this receiver is greatly understated as Yamaha is delivering MUCH more than specified. In fact, it's only a little less powerful compared to its bigger RX-Z11 sibling which is most real world cases, would likely go unnoticed. Unlike the Pioneer SC-07 (which utilized Class D ICE amplification) I had in review at the same time, the Yamaha did NOT have any issues driving 4 ohm loads at full power and bandwidth. The Yamaha was also a bit more powerful driving 8 ohm loads (170wpc vs 150wpc of the Pioneer). ...
Notice, however, that the review only rates the unit for one and two channels, not all channels driven! It also states:
... Note: With the receiver set to "less than 8 ohms" power dropped to 78wpc into 8 ohms and 144wpc into 4 ohms. Don't use this setting. Keep it at "8 ohms or more" always! ... Which clearly demonstrates the output limiting function of the lower impedance load setting ... and yet, in the "cons" listed by the reviewer, we find "Runs hot and needs adequate ventilation", which I would not consider a very good sign where difficult loads are concerned! In any case, OP, make your own mind up about this, but you may find this thread interesting too:
Furthermore, to confuse you beyond any possible salvation, you are likely to get recommendations for an external amplifier with at least 200w/ch @ 8 ohms any minute now. The same source has this interesting comment about amplifier power:
... What consumers fail to realize is almost no multi channel amplifier that is rated beyond 100wpc can meet the ACD specification for continuous power delivery on real world AC power lines. ... Now there's a little statement to get the flame war glowing hot! Here's a link to the rest of the document to feed those flames:
09-08-2009, 04:11 PM
I blelieve the Sunfire TGR401 will be about the only reciever truly capable of doing a proper job of driving a 4 ohm load, all channels driven. I know the high end Pioneers are capable to an extent, but my experience with Sunfire leads me to conclude that they can get the job done.
I blelieve the Sunfire TGR401 will be about the only reciever truly capable of doing a proper job of driving a 4 ohm load, all channels driven. ...I'm not sure how you arrive at that conclusion, but I certainly beg to differ! Any NAD will drive a 2 ohm load, and they are all rated for it (not just 4 ohms). They have also been measured to exceed their specifications in this regard during testing.
As an example, I currently use my comparatively modest T754, rated at 70W/ch (or 90W/ch in stereo), and am currently driving speakers rated at 3-6 ohms, with only 82.5dB efficiency. It will drive them at reference levels so effortlessly (over an extended listening period) that I don't even bother to engage the proprietary "soft clipping" circuit, which is designed to prevent possible damage from the effects of distortion. In fact, from what I can tell, NAD is probably the most cost effective way to drive difficult loads without an amplifier, since, as an entry level high-end product, they are priced below just about every Big Box Store flagship model. There are even very credible options well under $1,000.
The big question in such cases, however, is whether or not the receiver is able to deliver the full potential of the speakers, not just excellent results per se.
Not that any of this helps the OP, though, since it sounds as though he is not asking for suggestions on what receiver to buy ...
09-08-2009, 08:55 PM
sniper, did you go with the FXi for surrounds? As was discussed in your other thread, you may need to pick up a 3 ch amp. Leave the setting on 8 ohms, make sure the AVR has plenty of room to breath, use the powered sub in the Lsi25 and stay conservative with the volume. After you give it a try you will be able to decide if you need the amp. The LSi won't sound their best until you hit them with power, but you may be happy with them and the Z9 by itself. If you drive it to clipping or into protect mode, then you need the amp, or need to sell the LSi.
Just my $.02 which most will disagree with, for good reason, but as I said before the Z9 is one of a few mass market AVRs worth giving a try.
09-08-2009, 09:16 PM
I'm not sure how you arrive at that conclusion, but I certainly beg to differ! Any NAD will drive a 2 ohm load, and they are all rated for it (not just 4 ohms). They have also been measured to exceed their specifications in this regard during testing. ..
I arrive at that conclusion based upon the fact that the Sunfire receivers use exactly the same amplification that is inside their separate amplifiers, and they have no difficulty in pushing 400wpc to a 4ohm load at all channels, and will do so without breaking a sweat. Have I experience first hand with them, no, but I do run a Cinema Grand in my rig that has never been phased by my LSi-15's running at full volume for extended periods of time, and with 800wpc on tap to a 4ohm load.:)
09-11-2009, 12:55 AM
Thanks Jonh K . I keep the set up is 8 ohm and the Z9 run Lsi25 very good, the sound is perfec for me. Z9 can drive Lsi 25 in maximum level. thanks everyone here
09-11-2009, 08:28 AM
sniper, glad you are enjoying:) But again I would caution you on: "Z9 can drive Lsi 25 in maximum level"
If you mean drive them to a loudness level you are happy with using a moderate output level from the Z9, then you should be set.
If you mean you are driving the Z9 to the maximum output it has, you are asking for trouble.
09-11-2009, 08:40 AM
+1 on apphd's warning, that Z9 may be a beast, but be careful it's not bulletproof. Would be a pretty pricey thing to have to replace. The 25's are a hard speaker to keep happy without an amp at high levels. Things may seem ok at first, until it's too late. Enjoy.
09-12-2009, 01:54 AM
Thanks Apphd, good to see you here !
i have a little problem with shipping, can't get the Lsic and Micropro 2000 subwoofer, so i can only test the Z9 with Lsi25 for now. After a week try the Z9 and lsi25 ( not only me, i invited some of my friend ) all we can say it, the Z9 did really good job with Lsi25, we listen from classic, jazz , to hard rock. believe me, Z9 + Lsi25 never let you down with clear sound.
Yamaha Z9: Minimum RMS output power : 20Hz to 20kHz, 0.015% THD, 8 ohm ...170 W
Dynamic Power (IHF): 8/6/4/2 ohm . . . . . . 210/260/340/580W
out put power set at: 8 ohm
i keep tone control at natural: Bass control: -6 to +6 : keep at 0
Treble control: -6 to +6 : keep at 0
Set up for Lsi 25 subwoofer: volume control and frequency adjustment at factory setting
they blow up my house (and my neighbour house also) with clear sound. I will be back after i have all system for with Yamaha Z9, Lsi 25, lsic , Fxi A6 (x2 pair), Fxi A4 (presence) and MicroPro 2000 subwoofer. Thank again.
09-12-2009, 07:02 PM
Sniper, that is one nice reciever....try to make it last and get an amp.
09-12-2009, 07:44 PM
but I do run a Cinema Grand in my rig that has never been phased by my LSi-15's running at full volume for extended periods of time
Really? You have run your speakers at full volume for an extended period of time?
09-12-2009, 09:18 PM
Really? You have run your speakers at full volume for an extended period of time?I have my Yammi set to never go beyond the "0" db mark, and yes, when I am working out in the yard I crank it all the way up, sometimes running through 4 hours worth of cd's on the changer.:D
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