Impedence question

[pzaur]

Hello I am looking at the Marantz sr8001 receiver, I am trying to find out if this receiver can handle 4 ohm speaker load,I have looked at the specs of this receiver online but can't seem to find out this rating

Email/Call Marantz and ask them. They built the thing.

Here's the same question from audiogon.com with responses.

I would still email Marantz. You may be violating terms of warranty and thus voiding a warranty.

-pat

 

[mdrew]

It's obvious. If I cranked my system to max, something would be toast. Quickly, within seconds. There is no way you played an entire SACD cranked to max, let alone your following statement,"I could not detect any oddities of sound and the receiver did not shut down."

As for my balls, they are empty at the moment. Wife is knocked-up. I have a free pass.

And, that is how honesty is done.

Well at least you had the nuts to come clean and not hide behind another one of your cute faces (after being called out anyway). Now that I know you think the world is flat, I also know to ignore you. You have nothing of value to share but comparison’s to “your” system. I’m just wondering though, why have a volume control that goes from 0% - 100% if it can be operated at 100%?

At any rate, I stand by what I’ve wrote. I have no reason to lie, or to be condescending for that matter.

As far as calling Marnantz, they will tell you what any manufacture will tell you….. No, they do not ‘recommend’ that you use their product with a four ohm load. Call Denon or HK and you’ll get the same answer. Only a few like NAD, Rotel, BK or Bryston will tell you their product will drive a four ohm load.

 

[annunaki]

A marantz receiver should be fine with a four ohm load on the front two channels and eight ohms on the others.

 

[annunaki]

How high is really high? If I remember correctly the 8001's distortion (it didn't say if it was THD or not) was 0.1% at 205W into 4 ohms based on HT lab measurements. According to the manual, it is rated 125W into 8 ohms at 0.08% THD. Based on those figures, it should not clip unless it outputs more than 125W.

The amplifier is still able to output more power before clipping. The only way to see where the amplifier clips is to use an oscilliscope and check to see the output level in which the waves start squaring off. It is generaly accepted that distortion, with sine waves, is not heard until it reaches about .1% and even then it must be at higher frequencies (above 100hz-500hz depending upon the individual). With music it may be a fair bit higher.

If an amplifier is already at .1% thd at 125 watts rms, it is true that there would not be much dynamic capability left without hearing distortion or early onsets of clipping though.

Most people actually do not mind a slight bit of clipping as it is tough to percieve it at its earliest stages.

 

[mdrew]

The amplifier is still able to output more power before clipping. The only way to see where the amplifier clips is to use an oscilliscope and check to see the output level in which the waves start squaring off. It is generaly accepted that distortion, with sine waves, is not heard until it reaches about .1% and even then it must be at higher frequencies (above 100hz-500hz depending upon the individual). With music it may be a fair bit higher.

If an amplifier is already at .1% thd at 125 watts rms, it is true that there would not be much dynamic capability left without hearing distortion or early onsets of clipping though.

Most people actually do not mind a slight bit of clipping as it is tough to percieve it at its earliest stages.

Thank you for that intelligent and very understandable response. In light of this, I will accept the possibility that the Marnatz 8001 could very well have been clipping, although I could not detect it.

I have used several other receivers to power the same speaker set up in my HT room and I could quite clearly detect clipping at high volume levels in excess of 100 dbs with the other receivers. Those receivers were: HK 7200, HK 7300, HK 745 and lastly, a Yamaha 661. The 661 would shut down at approximately 75% volume, AFTER clipping was noticed. The 7200 faired the best out of all the HK’s, but was obviously straining when approaching max volume and I could detect sound degradation which I assume was mild clipping. All the other HK’s could not maintain the same volume level as the 7200 without sounding quite poorly. The 745 was the worst of the three HK’s. None of the HK’s would actually shut down, but I did not stress them after hearing clipping for more than a few seconds. The Marantz on the other hand was quite a surprise to me considering HK’s reputation for high current amplifier sections in their flag ship units. It was out of pure morbid curiosity that I ran the Marantz at max volume for as long as I did. I’m not sure how the Marantz differs from other manufactures, but I am assuming they use a current limiting design that prevents the units from going into an over current situation. Not being an EE, I can only speculate.

A marantz receiver should be fine with a four ohm load on the front two channels and eight ohms on the others.

While I am not advocating this receiver is the best choice for owners with 4 ohm speakers, I can elaborate with my speaker set up in mind. I am running M80's (4 ohm) for the FR / FL, twin M22's in parallel for the Center channel (4 ohm), QS-8's for the R/L surrounds (6 ohm) and M3's for the surround back R/L (8 ohm). All my high volume / max volume tests were done with PLIIx enabled so that I could detirmine where to set the max volume on each reciever to prevent damage.

 

[annunaki]

The only receivers I am aware of that advocate 4 ohm speaker usage on all channels would be from NAD (off the top of my head). I can see why you are running into an issue. Three 4 ohm, two 6 ohm, and two 8 ohm speakers will put most receivers under duress with higher volume situations. Especially when all channels are running such as PLIIx with music.

I would suggest a high quality receiver with good processing and a seperate amplifier(s) for the front two or three channels to start. If headroom is what you are after, I would suggest something like the Behringer EP2500. For the center(s) you could do an EP 1500 in mono. This would allow you to get the high output you are after and the dynamic capability without getting to the clipping point of the amplifier(s). The receiver should easily handle the rears at 6 ohms and 8 ohms.

With 750 watts a channel on tap for the front channels you will not reach the clipping point of the amplifier at all. If you hear anything, it will be the speaker begging you to back down. This will give you all the dynamic capability you will ever need.

Say an amplifer is rated at 125 watts rms at .1% thd. If said amplifier is producing 125 watts of rms output and a dynamic passage comes along that demands a 6db bump in output, it will clip that passage because it is already at it's limit for clean power output. If it has limiting circuitry it will just lower output for that dynamic passage. To achieve a 6db dynamic bump in output (at the speaker), it would require a 500 watt dynamic burst from the amplifier.

Running the above amplifiers sounds to me like it would solve you issue.

Please be advised you will be damaging your hearing listening at those levels.
125 watts rms on a speaker rated for 90db sensitivity 1w/1m will yield 111db at 1 meter. That is very loud. To get an extra 3db of output it would require 256watts of amplifier power.

 

[mdrew]

I agree with all the points you raise.

For clarification, I do not listen at extended high volume. An average of 85 db is about my threshold, and in my relatively small room (12 X 16 X 8), I really don’t need to employ separate amplification, but do need a receiver that will not shut down or clip at moderate DB levels. The only reason I entered this conversation was to give the OP some personal experience in regards to the receiver in question that he was asking about using with his 4 ohm speakers. I only tested the receivers for reasons of curiosity and to know what volume level to not exceed. (it happens after a few too many beers)

Prior to using the M80’s in my HT room, I had them in my great room where I have a two channel set up. The great room is 28 X 32 with vaulted ceilings of 23’. (big log house). When I had the M80’s in this room, I powered them with the Rotel gear in my sig. I never did pin the volume as it was just too darn loud to be remotely tolerable. Interestingly enough, when I bought the Wharfedale Opus 2’s for use in this room and with the same gear, I can not achieve the same volume level without the amp clipping (which very close to 100%, unlike when powering the M80’s). The Opus 2’s are a 6 ohm speaker, so I was surprised that they would pull more current than the 4 ohm M80’s.

 

[no. 5]

How high is really high?

Hmm, with speakers having 95dB/W/M sensitivity, I would Imagen it could be uncomfortably loud. Even if the amplifier cannot sustain much power into 4 ohms.

The amplifier is still able to output more power before clipping. The only way to see where the amplifier clips is to use an oscilliscope and check to see the output level in which the waves start squaring off. It is generaly accepted that distortion, with sine waves, is not heard until it reaches about .1% and even then it must be at higher frequencies (above 100hz-500hz depending upon the individual). With music it may be a fair bit higher.

I believe for 'program material' 3% THD is around the threshold, if you have good hearing.

I have casually messed around with that and have found that even higher levels of distortion can be less than a night and day difference.

 

[no. 5]

Prior to using the M80’s in my HT room, I had them in my great room where I have a two channel set up. The great room is 28 X 32 with vaulted ceilings of 23’. (big log house). When I had the M80’s in this room, I powered them with the Rotel gear in my sig. I never did pin the volume as it was just too darn loud to be remotely tolerable. Interestingly enough, when I bought the Wharfedale Opus 2’s for use in this room and with the same gear, I can not achieve the same volume level without the amp clipping (which very close to 100%, unlike when powering the M80’s). The Opus 2’s are a 6 ohm speaker, so I was surprised that they would pull more current than the 4 ohm M80’s.

Which model of Opus 2? Even the most sensitive of the models I looked up is 4dB lower in sensitivity than the M80's, so it will take more power to even get to the same SPL, not to mention differences in impedance curves, and phase angles.

 

[zumbo]

How can you guys keep having a serious conversation with someone who repeatedly claims using a volume of 100%, or close to it?

To further experiment, I left the room and used my RF/IR remote and turned the volume to max and let an SACD disk play from beginning to end. Even though I was not in the room, I could not detect any oddities of sound and the receiver did not shut down.

Only an idiot would do this.

Interestingly enough, when I bought the Wharfedale Opus 2’s for use in this room and with the same gear, I can not achieve the same volume level without the amp clipping (which very close to 100%, unlike when powering the M80’s). The Opus 2’s are a 6 ohm speaker, so I was surprised that they would pull more current than the 4 ohm M80’s.

I would assume they pull more voltage, not current.

 

[mdrew]

How can you guys keep having a serious conversation with someone who repeatedly claims using a volume of 100%, or close to it?

Only an idiot would do this.

The only idiot in this conversation is you. I’ve explained what my reasons were more than enough times for any moron with an IQ over fifty to grasp, which obviously, you do not possess.

You offer no value to this conversation, or any other from what I can tell by reading some of your other “helpful” posts on this sight. You do however seam to enjoy talking down to anyone with a different view or opinion than yourself, as if that automatically makes up for your lack of knowledge or expertise, which this statement clearly demonstrates……

I would assume they pull more voltage, not current.

I have better things to do than fight with some jerk on the internet when there is no way to hold that person accountable for his words by means of a good old fashioned *** kicking. Nor do I care to partake in further conversations on a sight that condones that type of behavior, which from what I can tell, happens quite frequently here. There will be no further replies from me to this thread, or any other on this sight.

 

[zumbo]

Just pointing-out the obvious. Most of the members on this site are more than happy to offer help, and opinions. But, when someone makes claims such as yours, it needs to be pointed-out so other people who are reading this thread don't go and turn their system to max volume because you say it's ok. It's simply not.

Well at least you had the nuts to come clean and not hide behind another one of your cute faces (after being called out anyway). Now that I know you think the world is flat, I also know to ignore you. You have nothing of value to share but comparison’s to “your” system. I’m just wondering though, why have a volume control that goes from 0% - 100% if it can be operated at 100%?

To further experiment, I left the room and used my RF/IR remote and turned the volume to max and let an SACD disk play from beginning to end. Even though I was not in the room, I could not detect any oddities of sound and the receiver did not shut down.

Prior to using the M80’s in my HT room, I had them in my great room where I have a two channel set up. The great room is 28 X 32 with vaulted ceilings of 23’. (big log house). When I had the M80’s in this room, I powered them with the Rotel gear in my sig. I never did pin the volume as it was just too darn loud to be remotely tolerable. Interestingly enough, when I bought the Wharfedale Opus 2’s for use in this room and with the same gear, I can not achieve the same volume level without the amp clipping (which very close to 100%, unlike when powering the M80’s). The Opus 2’s are a 6 ohm speaker, so I was surprised that they would pull more current than the 4 ohm M80’s.

So, to clarify, I am responding to you in order to help others. I am sorry if that offends you. No-one should turn their system to MAX volume. That is a stupid thing to do. I could care less that say you have done this to your system.

You offer no value to this conversation, or any other from what I can tell by reading some of your other “helpful” posts on this sight. You do however seam to enjoy talking down to anyone with a different view or opinion than yourself, as if that automatically makes up for your lack of knowledge or expertise, which this statement clearly demonstrates…

I would assume they pull more voltage, not current.

An 8ohm speaker requires more voltage, while a 4ohm speaker requires more current. My statement is valid, and correct. With this, one can see a 6ohm speaker will also require more voltage than a 4ohm, while the 4ohm will be more current hungry.

I have better things to do than fight with some jerk on the internet when there is no way to hold that person accountable for his words by means of a good old fashioned *** kicking. Nor do I care to partake in further conversations on a sight that condones that type of behavior, which from what I can tell, happens quite frequently here. There will be no further replies from me to this thread, or any other on this sight.

Sometimes, it takes a good debate to come to a conclusion. If we were all to take every post as it was written, I am pretty sure we would have some screwed-up systems. Each thread takes time to come to a solid conclusion. With you, it took much less time. You did not start this thread, but yet you act as if it is yours. With that in mind, I have every right to correct you if needed.