Can AV Receivers Handle 4 Ohm Speakers?

[PENG]

Like the amps sound same/different under any conditions or not, this kind of 4 ohm related questions always controversial and people would gave unqualified response, such as "no" if the device in question is an AVR. I would like to quote the following, by a respected speaker manufacturer:

"......like the myth (which refuses to die) that AVRs cannot drive a 4 ohm load without shutting off or bursting into flames. So it’s actually common (from a product sales and marketing standpoint) to state of nominal impedance of 8 ohms (even if it doesn’t meet the strict IEC definition) to avoid undue customer anxiety.

Probably the most transparent way to express impedance would be to state the minimum value along with an assurance that the speaker can be easily driven by any quality AVR – which is certainly the case with all XXX loudspeakers.

Some of our speakers do indeed have 4 ohm Zmin – and yet still remain very easy to drive by any decent AVR, even at high volumes - with no thermal shut-down. So in that sense, nominal loudspeaker impedance has become a spec which no-longer has any real-world relevance to the end-user – at least as it applies to XXX speakers......."

As I mentioned earlier, even the AVR-X1200W should be a good match for the OP's speakers based not only on specs but actual bench measurements. I just realize the AVR-X2200H's measurements were available on ASR. It has the same amp section as the OP's AVR-X2300W.

Denon AVR-X2200W Audio/Video Receiver Review

This is a review and detailed measurements of the Denon AVR-X2200W home theater AVR (processor and amplifier). It is on kind loan from a member. Looks like the unit was released back in 2015. I can't find the pricing on it but I am guessing US $700 when new. Used ones seem to go for as...

www.audiosciencereview.com

136 W, two channel driven into 4 ohms, at 0.022% THD+N. So it would not seem true to say the OP's AVR cannot handle 4 ohms, not as a blanket statement anyway.

Note from the graphs below, the X2200W actually measured better than the much more expensive NAD T758 V3 in terms of power output into 8 and 4 ohms.

 

[audiophool7878]

This kind of questions without the necessarily background information seem to get asked all the time and quite often get answered by people who just wouldn't bother to provide the conditions they based the answers on either, probably for good reasons.

The fact is, it depends on the several things, including but not limited to the following:

- Impedance vs frequency characteristics curve of the speaker, not just "4 ohms nominal".
- Phase angle vs frequency of the speaker, example: 4 ohm nominal+very benign phase angle may be better than 6 ohm nominal (even 8 ohm nominal in extreme cases) with terrible phase angles.

- Seating distance, this is a huge factor, the difference between 9 ft and 12.8 ft is 3 dB, so all else being equal, if you sit 9 ft from your 4 ohm speaker, for the same amplifier it would be like driving an 8 ohm speaker if you sit 12.8 ft from it, again, that's on all else being equal basis.

- The SPL you listen to, almost everyone on this forum knows for a 3 dB increase in sound pressure level, power requirement needs to be double. So if 85 dB average sounds very loud to you (as it is for most people), and you are currently find with an 8 ohm speaker, then you will be fine with a 4 ohm speaker if even 82 dB average sounds too loud for you (as it is for most people). Again, this is based on "all else being equal" obviously.

So one should not make a general statement, if think logically first, that receivers cannot handle 4 ohm speakers without specifying the conditions the statement is based on. By the way, many HTIAB kind of tiny satellite speakers have nominal impedance around 4 ohms or lower, yet the amplifiers that came with such packages are typically weaker than you Denon AVR-X2300W.

As an extreme example, consider the following:

Person A - Using a AVR-X4500H
- seating distance 9.5 ft

speaker specs:
- sensitivity 93 dB/2.83V/1m
- impedance 4 ohms nominal, minimum 3.5 ohms

SPL required at his mmp - 82 dB average, 102 dB maximum

Person B - Using a Yamaha CX-A5200 and MX-A5200, or an AT-2005 power amp
- seating distance 15 ft

speakers specs:
- sensitivity 87 dB/2.83V/1m
- impedance 8 ohms nominal, minimum 6 ohms

SPL required at his mmp - 85 dB average, 105 dB maximum (as loud as it is in a THX cinema)

If you do the math, you will see that Person A's AVR will have much easier time driving the 4 ohm speakers than Person B's power amp driving the 8 ohm speakers.

I hope I made my point clear about why one should not generalize by saying AVRs cannot handle 4 ohm speakers period, and/or power amps can do so period.

Regarding your current speakers, you can see the impedance and phase angles vs frequency graphs here:

SoundStageNetwork.com | SoundStage.com - NRC Measurements: Wharfedale Diamond 220 Loudspeakers

www.soundstagenetwork.com

It would appear that Whafedale specs of 8 ohm nominal, 86 dB sensitivity are not reflected by the lab measurements that show 84.7 dB/2.83V/1m sensitivity and the nominal impedance looks more like 6 ohms to me.

So in your current system, the weak link is actually the Diamond 220, not the entry level Denon AVR.

If you are getting the M5, or M7, you will be in the same or worse situation as you already know the M5/M7 have similar or even lower sensitivity and they can barely handle the rated output of even the AVR-X2300W.

• Frequency Response: 100 Hz – 20 kHz ±2dB
• Impedance: 4 Ohms
• Power Handling: 80 Watts RMS
• Sensitivity: 84,5 dB
• Weight: 2,2 kg

Based on that, again your concerns should not be the Denon AVR, but your SPL requirement at your seating position.

Even the X1200W measured with the following results by S&V:

Denon AVR-X1200W A/V Receiver Review Test Bench

Test Bench This graph shows the AVR-X1200W’s left channel, from Audio1 input to speaker output with two channels driving 8-ohm loads.

www.soundandvision.com

At 0.1% THD:

- 139.2 W into 4 ohms, 2 channel driven
- 69.9 W into 4 ohms, 5 channel driven
- 47.4 W into 4 ohms, 7 channel driven

It seems to me your Denon is a good match for the M5 and M7.

Peng, I don't see any specs for 5 or 7 channels driven @ 4ohms when I checked the link you provided.

	0.1% THD	1.0% THD
2 Channels Continuously Driven, 8-ohm Loads	112.8 watts	126.1 watts
2 Channels Continuously Driven, 4-ohm Loads	139.2 watts	164.3 watts
5 Channels Continuously Driven, 8-ohm Loads	69.9 watts	78.8 watts
7 Channels Continuously Driven, 8-ohm Loads	47.4 watts	57.9 watts

 

[PENG]

Peng, I don't see any specs for 5 or 7 channels driven @ 4ohms when I checked the link you provided.

	0.1% THD	1.0% THD
2 Channels Continuously Driven, 8-ohm Loads	112.8 watts	126.1 watts
2 Channels Continuously Driven, 4-ohm Loads	139.2 watts	164.3 watts
5 Channels Continuously Driven, 8-ohm Loads	69.9 watts	78.8 watts
7 Channels Continuously Driven, 8-ohm Loads	47.4 watts	57.9 watts

Soundandvision.com rarely did 5,7 channel driven into 4 Ohms, they might have done it a few times.

Such tests are really meaningless because given a budget, the consumers are better served by manufacturers who take a practical and balanced approach. That means try harder to maximize/optimize the 2 to 3 channel driven output for the LCR channels. You will find it rare that any contents would have the ambient channels demanding as much as the LCR. Even on those rare occasions that they might, the odds that all would peak at the exact same moment would be extremely low.

People used to favor HK and NAD for their 5, 7 channel output, not knowing that they were getting the short end of the stick because those AVRs were often much weaker than the likes of Denon, Marantz, Yamaha, Anthem and Sony's in practice, because of their much lower 2,3 channel output, and in many cases even in 5 and 7 channel output. That's likely because (imo) they over spent their budget on the most expensive part, the power transformer so they have to cut back somewhere, likely the amp section.

If you must see such mostly irrelevant tests, try audiovision.de. I don't know why their site's resolution is so poor making it very hard to decipher the X-axis that is for the number of channels. I had even bought a report from them, but the resolution was the same, still hard to read. Occasionally they would somehow publish one that was barely legible, but legible, such as the one linked below:

The 3rd and 5th columns are the the 5 and 7 channel driven into 4 ohms respectively. Keep in mind too, such test were likely conducted using a regulated power supply to hold the voltage constant, and for sure the tests were of short duration. Also, they did not specify the distortion level, I would assume 1%, as that's a typical standard used by many test benches, but we don't know that for sure. Bottom line, we can use the data for comparison purposes of the units they measured on their site only, even then, I would use them as rough guidelines only, but won't take it too seriously.

So in their test, the RX-A1070 measured 136 W, 5 channel driven, and 86 W, 7 channels driven.

Yamaha RX-A1070 (Test) – audiovision

 

[PENG]

Again, unless the AVR, or amp has protective circuitry that could be too aggressive, there is no such thing as 4 ohm rated without specifying the load conditions based on the following:

1) Required SPL at a specified distance.
2) Duration of the load at the specified lowest impedance.

Otherwise one can say that any av receivers, audio receivers, amplifiers can drive 4 ohm, or even 2 ohm speakers.
A good example of how misleading this kind or 4 ohm rated AVRs can get the technically uninformed read the article in the link shah122 just posted. Those AVRs are rated for 4 ohms under the condition that the user set the so called impedance setting to 4 ohms, enough said.....

Okay, may be one more just in case, consider the following:

Most readers understands Ohm's law right, that is V=IR, or I=V/R

So take the weakest AVR that may be rated say, 70 WPC, 8 ohms and the calculations based on I=V/R and Power = I^R, or V^/R, or V*I, you can see that such an AVR can be rated under the same rules for the 70 WPC 8 ohms:

Keep in mind P = I^R, so I = square root (P/R) and you can see that under the following load conditions, the current would be the same, and there should be no need for the protective schemes to spoil the fun if there are properly designed.

70 W...................8 ohms
35 W...................4 ohms
17.5 W............... 2 ohms

Now look at it another way, if the user turns the volume up high enough, the AVR will trip (shutdown) when if the load is in fact 8 ohms. So even that 8 ohm rating is only good if the user is intelligent enough to use common sense.

It is a mess created by those who started rating amps output based on power/watts, same kind of mess about the power consumption specs.