Will 4 ohm's hurt in anyway?

[scoodilywoo]

Hello eveyone! I normally don't ask for help but this time I'm going to. I have an Harman/Kardon AVR 247 Receiver and I was wondering. Would it damage my receiver if I used 4ohm speaker's? On the back it does say 8ohm, But doesnt state it's minimum... :/ I want to use a pair of "Dayton MK442T" and other "Dayton Audio" Speaker's for the surround and they are 4ohm's as well. I already know that the receiver get's hot using 8ohm speaker's even on low volume. I just don't want to blow a channel or something using 4ohm's. How could I go about doing this or can I do it at all? Thank's to anyone willing to help me out.

 

[Pandaman617]

Hello eveyone! I normally don't ask for help but this time I'm going to. I have an Harman/Kardon AVR 247 Receiver and I was wondering. Would it damage my receiver if I used 4ohm speaker's? On the back it does say 8ohm, But doesnt state it's minimum... :/ I want to use a pair of "Dayton MK442T" and other "Dayton Audio" Speaker's for the surround and they are 4ohm's as well. I already know that the receiver get's hot using 8ohm speaker's even on low volume. I just don't want to blow a channel or something using 4ohm's. How could I go about doing this or can I do it at all? Thank's to anyone willing to help me out.

This is just an assumption on my part so please read your user manual as I always run a Denon/Marantz setup with external power amps for my LRC. But it’s very possible that if the impedance seen by the AVR is too low it will go into a protection mode and shut down before any significant and permanent damage can occur. I could very well be wrong however. Does your Harmon have preouts? You could pick up a cheap 4ohm power amp if needed.

 

[Trebdp83]

The Daytons are not exactly efficient but the receiver has pre outs. I run two pair of the MK442Ts and an MK442 center channel and things can get warm after hours of spirited listening.

 

[scoodilywoo]

Yeah it has preouts, and I do have stereo 4ohm amp's. So your saying use the pre amp's to the external amp that has 4 ohm loads, and run it that way? I have no idea why I didnt think of that lol.... Thank's for pointing that out to me Would i be able to still use the menu from the receiver to setup the distance of the speaker's etc?

 

[scoodilywoo]

The Daytons are not exactly efficient but the receiver has pre outs. I run two pair of the MK442Ts and an MK442 center channel and things can get warm after hours of spirited listening.
View attachment 50301

Ok i got the same speaker's as you mentioned

 

[warnerwh]

Yes you will still be able to use the menu from the receiver.

 

[scoodilywoo]

All these receiver's I have and never once have I thought about using the pre-out's.... I'm disappointed in myself I'm setting this up with the dayton's that are mentioned and 2 TS14 harman/kardon subs. though I replaced the speakers in the subs with a pair JBL Stage 1010. I made spacers for them because the sub boxes are made for 12's and I wanted 10's... I love the original's their just to big sounding for a smaller room. the 10's do sound better all around but I still need to play around. Now that you's helped me out Thanks to you guys for helping me so far!

 

[scoodilywoo]

Yes you will still be able to use the menu from the receiver.

Perfect!

 

[ryanosaur]

Put some active cooling on top like an Aircom T8 from AC Infinity or similar. Unless you find the Amps in your AVR expressly are not designed for 4-ohm loads.

 

[TLS Guy]

Hello eveyone! I normally don't ask for help but this time I'm going to. I have an Harman/Kardon AVR 247 Receiver and I was wondering. Would it damage my receiver if I used 4ohm speaker's? On the back it does say 8ohm, But doesnt state it's minimum... :/ I want to use a pair of "Dayton MK442T" and other "Dayton Audio" Speaker's for the surround and they are 4ohm's as well. I already know that the receiver get's hot using 8ohm speaker's even on low volume. I just don't want to blow a channel or something using 4ohm's. How could I go about doing this or can I do it at all? Thank's to anyone willing to help me out.

The real thing you have to understand is that almost all speakers are in fact four ohm, even if the manufacturer gives them an eight ohm rating at the insistence of their marketing department.

 

[Leemix]

Does it have a lot of air around it or is it stuck in a cubbyhole?
ABRs like a lot of air or active cooling but since this is at low volume it will probably get just as warm when on and not playing anything. The volume dial is what decides how hard it has to work, low volume is nothing at all, a watt, maybe a few only and thats no problem at all with a 4ohm speaker. The difference comes when you turn up to loud.


Sent from my iPad using Tapatalk

 

[PENG]

Hello eveyone! I normally don't ask for help but this time I'm going to. I have an Harman/Kardon AVR 247 Receiver and I was wondering. Would it damage my receiver if I used 4ohm speaker's? On the back it does say 8ohm, But doesnt state it's minimum... :/ I want to use a pair of "Dayton MK442T" and other "Dayton Audio" Speaker's for the surround and they are 4ohm's as well. I already know that the receiver get's hot using 8ohm speaker's even on low volume. I just don't want to blow a channel or something using 4ohm's. How could I go about doing this or can I do it at all? Thank's to anyone willing to help me out.

Any receivers can drive 4 ohm speakers depending on your volume setting, or if you sit close enough to the speakers and don't listen so loud as to push the amp to its clipping point. That being said, it is true that on "all else being equal" basis, if the speaker's impedance is rated nominal 4 ohm with "power handling" of 80W RMS/160W max such as that of the Dayton MK442T then in general it is not a good idea to use the AVR 247 rated only 50 W 8 ohms. Again, it depends, and you will know better if you find out your real power need for you application. You can use an online calculator to figure that out.

The AVR247 may be conservatively rated for 50 W 8 ohm but they are still not 4 ohm rated so the best you can assume is 50 W for 4 ohm, probably 75 W for very short duration.

 

[highfigh]

TLSGuy posted that "all 8 Ohm speakers are 4 Ohms", but the reality is, they'll reach 4 Ohms for some frequencies, higher for others and if you read the specs, the impedance should be referred to as 'nominal', which is their way of saying "around 8 Ohms".

 

[PENG]

TLSGuy posted that "all 8 Ohm speakers are 4 Ohms", but the reality is, they'll reach 4 Ohms for some frequencies, higher for others and if you read the specs, the impedance should be referred to as 'nominal', which is their way of saying "around 8 Ohms".

Don't all know TLSGuy enough to know why he would say those things by now?

 

[TLS Guy]

Don't all know TLSGuy enough to know why he would say those things by now?

Well I'm in good company now! That team of very experienced speaker designers, that Gene assembled for the video on speaker specifications, made the exact same point I have been making for years. All audio amps and receiver do need to be 4 ohm capable and stable, period.

 

[M Code]

The AVR247 will drive 4 Ohm loudspeakers just fine, but to comment further U need to confirm a few points:
1. Does the 247 have the 4-5" free-air clearance for the L/R sides and top cover?
2. What is the average volume level?
3. Size of listening room
4. Type of source material, compressed or uncompressed?
5. Are U using it in 5.1 or 7.1 mode, if 7.1 power supply demands will be higher

Since we were the lead design engineer for the 247 we do know little about it.. Note that the 247 will run hot @ idle and low output, as it biased high to minimize x-over distortion. The 247 amplifier section was designed by R.Miller of HK New York, who designed some of the highly rated HK Citation amplifiers and does handle 4 Ohm loads just fine within reason.. The 247 does have built-in fans if the internal temperature climbs too high.. Note that the mentioned Dayton MK442T loudspeakers besides being 4 Ohm, have a low sensitivity spec of 87dB so they do require significant current to drive to higher SPL levels. The 247 was an entry-level AVR and now is 15 years old so it is dated but in its day was 1 of the top selling AVRs world-wide...

Just my $0.02...

 

[EBN]

I had newer higher range HK receiver many years ago, 355 perhaps? So long time ago. I remember the "polite" wattage figures on spec sheet, but some site or hifi magazine measured it and it showed more than competitors. Enjoyable product it lasted 8years with me. I remember it weighted ton, similar to flagship Yamahas. After that one they made some slim receiver before the company stepped down with the av-gear.

As for the 247 model spoken here i found German test which said:

The AVR-247 comes with a seven-channel power amplifier that mobilizes 50 watts per channel in surround mode (sine output at 8 ohms, 0.07% THD, 20 Hz to 20 kHz). That doesn't sound like excessive power reserves, but if you look at the conditions under which Harman Kardon states the power, this puts the impression into perspective. Because other manufacturers like to measure according to non-practical specifications (e.g. at a fixed frequency of 1 kHz and not over the entire spectrum of a DD / DTS full frequency channel from 20 Hz to 20 kHz, often only 1 channel is controlled at a time). In practice, this means that in the case of counterparties who can boast power of 100 watts and more per channel according to the technical data, under identical measurement conditions as with the AVR-247, no more power is actually available, but often guaranteed less power is actually available. In all of the test series, we notice again and again how stable and powerful Harman Kardon AV receivers are. This also proves the high current capability of +/- 35 amps in the case of the AVR-247.

 

[PENG]

Don't listen to hearsay, check out many bench measurements by S&V, HCC, and others. HK's avrs almost always had lowered output into 4 ohms on the test benches than D+M's in the same price range, except the 7000 and 8000 series.

Again, any AVR can drive 4 ohm speakers under the right conditions that M Code and I have mentioned. Another thing, you can have a 50 W 4 ohm rated power amp, and a 120 W 8 ohm rated RX-A2080, which one is more capable driving 4 ohm speakers for stereo listening.

This sort of questions and answers on 4 ohm speakers and amps can get silly.

 

[scoodilywoo]

Ok I've put all of you into thought... I'm not a professional i this area, but I'm gonna take a swing at this and act like I bought some sylvania equipment... That of course was just being an example of cheap lol. But i'll hook it up without external amp's first and try it out on some movie's and music different volume's of course and let you all know what I get outta of it. If i do hurt the receiver I have another one which is the avr 136. The problem with that is the ananlog bass and treble knobs I think are ugly. I havent even used it but it work's. So again, I'll give it a go and hope to update you's asap! I'm also gonna check that fan thing going on. I don't recall any fan's inside but I didnt open it up either. I just didnt hear any, maybe thats good. But ok t2ul! Oh and thx!

 

[PENG]

Ok I've put all of you into thought... I'm not a professional i this area, but I'm gonna take a swing at this and act like I bought some sylvania equipment... That of course was just being an example of cheap lol. But i'll hook it up without external amp's first and try it out on some movie's and music different volume's of course and let you all know what I get outta of it. If i do hurt the receiver I have another one which is the avr 136. The problem with that is the ananlog bass and treble knobs I think are ugly. I havent even used it but it work's. So again, I'll give it a go and hope to update you's asap! I'm also gonna check that fan thing going on. I don't recall any fan's inside but I didnt open it up either. I just didnt hear any, maybe thats good. But ok t2ul! Oh and thx!

Have you figured out how much power you actually would need for you listening habit? If not, please do it and report back the results so we can give further suggestions. Until then, try not to listen too loud, and use an external fan too if you have one.

Peak SPL Calculator (hometheaterengineering.com)