4 ohm Speakers on Cheap Receivers: Recipe for Disaster?

so what happens when you connect 4-ohm speakers to cheap av receivers or cheap two-channel receivers that's the question we're going to be answering in today's video hey folks i'm gene delasallo with audioholics i want to answer this very important question because i get it all the time people want to have 4-ohm speakers on cheap inexpensive receivers whether they be two channel receivers or multi-channel receivers they want to know what happens they want to know what the net effect is by hooking up a pair of four-ohm speakers or two pairs of eight-ohm speakers in parallel which will give you four ohms equivalent to an av receiver to a two channel receiver well the short answer is if it's a really cheap lightweight receiver with not a lot of heatsink area there's probably two scenarios that'll happen either the receiver will shut off as you turn the volume up on a low impedance load which is mostly what happens or it'll current limit meaning that it won't give you as much power as you think so let's talk about what an amplifier is supposed to do an ideal amplifier should double its power with having load impedance that's what an ideal voltage source does so if you had an amplifier that's rated at 100 watts of channel and 8 ohms theoretically you should get close to 200 watts when driving a 4 ohm load that happens on the very best amplifiers you can see in the measurements that we've done on amplifiers like the class a 2 channel lamp the ct 2300 which i love that amplifier doubled down with having load impedance but that's a really killer very expensive amplifier with a big power supply big heatsink area you don't get that kind of power you don't get that kind of finesse that kind of engineering prowess you don't get that in an inexpensive receiver especially a two-channel receiver in this in this topic i want to talk about i saw a video from another youtuber that was saying oh my god this hundred dollar sony receiver is an audiophile dream machine you can plug two pairs of speakers into it simultaneously and run your whole house you can't do that this is why measurements matter this is why being objective that same receiver that this guy gushed over if you look at the measurements from audio science review the receiver did okay in eight ohms but it could not drive a forum load it would shut down and i've seen the same thing i measured a yamaha years ago yamaha 8 a860 from the aventage line the measurements were pretty decent into 8 ohms but when it ran a 4 ohm load you saw like this nike swoosh symbol as you got to its max power it started current limiting so that 200 watts you think you're gonna get in four ohms you're lucky if that thing is driving more than maybe a hundred watts and if you're doing it over a sustained period of time for a really low impedance load you're going to be current limiting you could potentially damage that product now i know what someone's going to say down below they're going to say well let's just use the impedance switch let's set it to 4 ohms and our all our problems are solved that again is not true my friends you've known for over the last couple of years when i did those videos back when hugo was on the channel we did a whole video on the impedance selector switches how you should never use them always leave them on the 8 ohm setting the only reason why that impedance selector switch is there is so that receiver could get a ul stamp that it's safe to drive a four ohm load because it's power limiting as soon as when you flip that switch to four ohms you're cutting your power down sometimes down to maybe 25 watts maybe a quarter of the rated power at eight ohms when you select that peat and switch to the low setting never use that setting that's only there for ul test certification no other purpose to it that's how the receiver manufacturer can cheat and say that their receiver can drive a forum load when it really can't and the reason why you can't again is when you're dealing with a budget product there's not a lot of heat dissipation they don't have enough heat sink area especially if it's a high if it's a high channel count receiver like a seven or nine channel receiver and it's using small heat sinks their power output devices just can't drive enough current they can't dissipate that power usually the power supplies are undersized so that voltage that comes out of that transformer will saturate and it just can't handle those low impedance loads so here's what i recommend if you are going to run low impedance speakers and let's let's also mention the fact if you get a speaker that's rated nominally at ohms or nominally at four ohms it's not really an eight ohm or a four ohm load that impedance fluctuates with frequency if the loudspeaker manufacturer is honest they'll rate that speaker to an iec standard which says that that speaker can drop more than 80 percent of its nominal rating between 300 hertz and three kilohertz okay but that's not always the case we've seen many eight ohm speakers that dip down to the four or five ohm rating and they honestly should be rated as a forum speaker some of the manufacturers will rate them as six ohm speakers to get around it but my point is if you take two 8 ohm speakers and you put them in parallel which is what this youtuber was recommending that 8 ohm load now becomes a 4 ohm load to the receiver and that's what's going to cause either current limiting or it's going to shut down the receiver or over long term because of extra heat dissipation that that receiver can't really do well it's going to reduce the longevity of the product and the one thing i don't want you guys to do is overheat a product i don't want you to current limit either because in some cases when you flip that switch to 4 ohms that receiver is going to clip sooner so what's going to happen is that nice sinusoidal wave that music wavefront is going to be more like more like a square wave and what happens when you have a square wave with a long duty cycle you could fry a tweeter because that tweeter is basically seeing dc voltage and you don't want to do that you don't want to underpower your speakers that's a topic for another video that we could do but the bottom line is if you're going to drive 4 ohm loads on cheap receivers i either recommend you use external amplification if you receive as preamp outputs or your other option is to get a speaker impedance matrix switch if you're going to run multiple speakers across a 2-channel receiver use an impedance switch you know it's like they're kind of outdated they don't really do that anymore if you're gonna run distributed audio throughout your house you're better off using a distribution amplifier there's companies like triad martin logan paradigm that do excellent excellent 8-channel 16-channel amplifiers that'll run your whole house that's the better way to do it don't try to overwork your av receiver or your 2-channel receiver i've been in a lot of installations where i've seen builders that didn't know any better they just ran a bunch of speakers in the house and they tied them all together in power parallel back to the receiver that receiver now sees like a 0.2 ohm load and crank that volume up it's going to shut it down it's going to cause problems avoid those problems always trust the measurements when if something sounds too good to be true if someone's going to tout that this hundred dollar receiver is audio nirvana audio bliss it's going to make your speakers open up and your mid-range more chocolaty just realize there's a grain of salt you have to take that with a grain of salt because there's only so much you could do on a budget and i'm not bashing a budget product budget products are great for what they do but they got gotta be used within the limits that they're designed for don't go and drive a pair of bmw nautilus speakers on a 100 sony receiver you're not going to get the greatest results so guys i hope you found this video useful please share it please thumb it up please make sure you subscribe to this channel if you aren't already don't forget about our patreon channel at patreon.com audioholics you get direct access to me if you want to ask questions you can send us topics you'd like us to discuss on youtube and most importantly you help support the channel we always appreciate that and don't forget about our marantz contest that's running until the end of december we're giving away a marantz av 7705 11 channel processor one lucky person's gonna win that make sure you enter i'll put the link down below and until next time my friends keep listening are you ready hit record you're recording is it on are you sure 100 no i'm not ready okay like my shirt yes i take this for you yes i do thank you okay that old neck old neck injuries okay

Channel: Audioholics

Views: 43,920

Keywords: audioholics, video review, home theater, audiophile, tech, headphones, speakers, amplifier, movies, music, audio, video, projection, bass, subwoofer, hdtv, blu-ray, dolby, atmos

Id: Xx74hQ0MjRw

Length: 9min 7sec (547 seconds)

Published: Mon Dec 14 2020