4 ohm speakers on 6-8 ohm receiver

B

Brewdawg

Member
I know there are a bunch of threads on this, but...I figured if I gave my equipment, answers might be more specific to me:

Sony STR DH90 (90w/ch) receiver, specs say 6-8 ohm. Using a Dayton Audio 1200 sub, connected from B speaker outputs to high level input. It's powered, of course, so I'm not even sure if that has an effect, with using the B speaker line.

I was looking at a pretty good deal on Sonus Faber Lumina II, but they're rated at 4 ohm.
I typically have relatively short listening sessions (about an hour), at about 70-75db in a 16x22' room.

I've seen many say that I should be fine as long as I don't play too loud, too long, and stop if I hear clipping. And that the receiver would likely be the fail point, with most have built in protection.

So, thoughts? If the receiver fails, that'd be the preference. It's obviously not as expensive as the speakers. But of course, I'd rather not replace it, and definitely wouldn't want to pay for the speakers and damage them. And also, I have a Yamaha RX-V481 (110w/ch) I could use if better suited with more wpc, but it's also 6-8 ohm. So how "safe" would it be using the Lumina, and which receiver would be better to use?
 
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You risk damaging either the Sony or the Yamaha.

They specify 6-8 ohm for a reason, if they could safely handle 4 ohm loads they would be rated as such.

As they are HT receivers they are designed to run 5 - 7 speakers or more, if you only run the two speakers you could be ok.

Keep an eye on how warm the receiver gets and shut it down if it gets hot or starts to sound strained.
 
Sandman1221 said:
Not an expert, but those are two-way bookshelf speakers and should not draw that much watts/current even when played reasonably loud. A 90 w/ch receiver should be fine with them, I think the problem would be turning the receiver volume up too high for the speakers, but speakers are rated for 150 W so you should be fine.

For a 16x22 room I would want some tower speakers
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You need to read up on speaker sensitivity. Small speakers usually require more power. The Lumina 2 is pretty low sensitivity, 86 dB.
 
Sandman1221 said:
You are a real BSer! Here is a screen shot of your first link, in it NAD 317 is only rated for 8 ohm, and those specifications are very incomplete compared to what I posted above.

Now I remember why I hid your posts in the first place.
Click to expand...
The NAD 317 is rated to handle 4 ohm speakers in stereo mode. The rear of my unit clearly shows that rating. The linked info showing the sales specs only shows the rated power output at 8 ohms, it does not say anything about 4 ohm ratings. The markings on the actual equipment take precedence. My NAD does a fantastic job driving my 4 ohm Epicure 20+ at any volume level.

2023-09-20 NAD 317 Rear serial number.jpg

As for the OP's Sony, I could not find a picture of a STR DH90, but I found a picture of a STR DH190 where the rear shows the receiver is rated for 6 to 8 ohm speakers. Although as noted above, it is likely that the OP will be fine as long as he operates it as he says, moderate listening levels for relative short periods.

The Sonus Faber speakers seem to present a reasonable load. According to this page, the lowest impedance above 80 Hz is 4.1 ohms and the EPDR bottoms out at 2.2 ohms. I would expect the Sony to be able to handle that load reasonably well, provided the receiver is not run near full output for extended periods of time. The OP should be aware that he is potentially operating the receiver within its safety margin and excessive power to the speakers may overly tax the receiver. Considering that OP is using a subwoofer for the bottom end, it would be best if there was a high pass filter for the Sonus so the sub handles the low frequency range and the Sonus plays the frequencies that the sub doesn't.
See the Impedance Chart at https://www.erinsaudiocorner.com/loudspeakers/sonus_faber_lumina_ii/
 
Here we go again saying 75 db, when we don't know under what parameters the readings were taken. The actual peak levels might be as high as 90 db. In order to protect your amp I would want a 100 HZ high pass filters on the speaker outputs feeding the full range speakers to help protect the Sony amp if you want to use it to drive the main speakers. Some subs have the High Pass filters built in the protect the stereo speakers when using the sub with High Level signals.
 
Sandman1221 said:
They are 2-way bookshelf speakers, compared to my tower A500s with 10" woofers. Speaker Power requirements are dependent on the size and number of drivers. There is no way they could draw anywhere close to what my speakers draw "at the same volume position on an amplifier". And in this case we are comparing 4 ohm speakers.

This is fun, but it makes me wonder
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You are over simplifying. Sensitivity is based on more than the number of drivers and their size. I have a small pair of bass reflex bookshelf speakers (1" dome tweeter, 6" mid-woofer) that have a sensitivity of about 85 dB. They probably weigh 15 lb. each. In comparison, also have a pair of bass reflex floor stander Tyler Acoustics PD15s that have a 15" woofer and 1" compression drive/horn and a sensitivity of >=100 dB. The weigh over 100 lb. each.
 
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RTally said:
The NAD 317 is rated to handle 4 ohm speakers in stereo mode. The rear of my unit clearly shows that rating. The linked info showing the sales specs only shows the rated power output at 8 ohms, it does not say anything about 4 ohm ratings. The markings on the actual equipment take precedence. My NAD does a fantastic job driving my 4 ohm Epicure 20+ at any volume level.

View attachment 3297878

As for the OP's Sony, I could not find a picture of a STR DH90, but I found a picture of a STR DH190 where the rear shows the receiver is rated for 6 to 8 ohm speakers. Although as noted above, it is likely that the OP will be fine as long as he operates it as he says, moderate listening levels for relative short periods.

The Sonus Faber speakers seem to present a reasonable load. According to this page, the lowest impedance above 80 Hz is 4.1 ohms and the EPDR bottoms out at 2.2 ohms. I would expect the Sony to be able to handle that load reasonably well, provided the receiver is not run near full output for extended periods of time. The OP should be aware that he is potentially operating the receiver within its safety margin and excessive power to the speakers may overly tax the receiver. Considering that OP is using a subwoofer for the bottom end, it would be best if there was a high pass filter for the Sonus so the sub handles the low frequency range and the Sonus plays the frequencies that the sub doesn't.
See the Impedance Chart at https://www.erinsaudiocorner.com/loudspeakers/sonus_faber_lumina_ii/
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Yes, correct- DH190, sorry. I know little to nothing of audio science, but looking at the chart, you're looking at this area, right? Impedance seems to stay above 6 ohm above ~350 hz.
1726410606011.png
twiiii said:
Here we go again saying 75 db, when we don't know under what parameters the readings were taken. The actual peak levels might be as high as 90 db. In order to protect your amp I would want a 100 HZ high pass filters on the speaker outputs feeding the full range speakers to help protect the Sony amp if you want to use it to drive the main speakers. Some subs have the High Pass filters built in the protect the stereo speakers when using the sub with High Level signals.
Click to expand...

Sorry, I didn't know I was "going again." It's just an android app, sampled at main listening area, and seemed to rarely peak at almost/around 80 (but I was sober at the time, so I could see going slightly higher sometimes). I'm not sure what other parameters would be helpful.

But looking at the chart, it seems like ideally, I'd want higher than 100 Hz to be safe- even though I might be safe enough if I don't push the system beyond what's described? Would something like this work? It's listed for cars, but I'm not sure why that would matter- except maybe the guage of the wire. All the others I've found look as if they're for building crossovers, or really expensive component units.
1726410796115.png
 
RTally said:
The NAD 317 is rated to handle 4 ohm speakers in stereo mode. The rear of my unit clearly shows that rating. The linked info showing the sales specs only shows the rated power output at 8 ohms, it does not say anything about 4 ohm ratings. The markings on the actual equipment take precedence. My NAD does a fantastic job driving my 4 ohm Epicure 20+ at any volume level.

View attachment 3297878

As for the OP's Sony, I could not find a picture of a STR DH90, but I found a picture of a STR DH190 where the rear shows the receiver is rated for 6 to 8 ohm speakers. Although as noted above, it is likely that the OP will be fine as long as he operates it as he says, moderate listening levels for relative short periods.

The Sonus Faber speakers seem to present a reasonable load. According to this page, the lowest impedance above 80 Hz is 4.1 ohms and the EPDR bottoms out at 2.2 ohms. I would expect the Sony to be able to handle that load reasonably well, provided the receiver is not run near full output for extended periods of time. The OP should be aware that he is potentially operating the receiver within its safety margin and excessive power to the speakers may overly tax the receiver. Considering that OP is using a subwoofer for the bottom end, it would be best if there was a high pass filter for the Sonus so the sub handles the low frequency range and the Sonus plays the frequencies that the sub doesn't.
See the Impedance Chart at https://www.erinsaudiocorner.com/loudspeakers/sonus_faber_lumina_ii/
Click to expand...
Yeah, mine says the same on the backside of the case, good to know, so 4 ohm with "only one pair" of speakers. Thanks for clearing that up! So you cannot go just by the technical specs sheet. Maybe the OP should check with the manufacturer?
 
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I had a Pioneer VSX-1016TXV 5 channel AVR that was for 6-8 Ohm speakers and you had to set on the receiver which you were using. I forgot and hooked up 4 ohm speakers. After 15 minutes listening at a moderate level the receiver's front L&R channels blew. Speakers were fine.
 
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So from the back panel, the Sony STR D990 can run two pairs of 4 ohm speakers using the "Center Speaker" inputs, but not finding a Sony STR DH90 anywhere.

Has the OP checked the back of their unit? The STR D990 also says 8-16 ohm speakers, but makes a 4 ohm speaker exception for the center speakers, see 2nd picture.

On the STR DH800, 1st picture, the minimum ohms for all speaker channels is 8 ohm.

Based on Mr.White's comment above, I would only use 4 ohm speakers on speaker channels rated for 4 ohms.
 

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Sandman1221 said:
So from the back panel, the Sony STR D990 can run two pairs of 4 ohm speakers using the "Center Speaker" inputs, but not finding a Sony STR DH90 anywhere.

Has the OP checked the back of their unit? The STR D990 also says 8-16 ohm speakers, but makes a 4 ohm speaker exception for the center speakers, see picture.
Click to expand...

One channel/single amplifier/mono, 2 speakers wired in series doubles the impedance for the amplifier.
 
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