quickshot Posted January 13, 2007 Posted January 13, 2007 Hi guys, like to seek any member's opinions here regarding thread title. If my amp specs at 75w per channel, what will the difference be if it is matched by a 50w or 120w speaker? will the 50w speaker will overloaded and incur damage in the long run? Or will the amp lack sufficient power to drive the 120w speaker? Any guidance or experience will be appreciated, cheers!
rahul Posted January 13, 2007 Posted January 13, 2007 You would have no problem driving your 50w or 120w speakers with a 75wpc amp. Just avoid very loud volumes where you might get distortion. Otherwise your speakers are safe.
petetherock Posted January 13, 2007 Posted January 13, 2007 Try this: http://www.avsforum.com/avs-vb/showthread.php?t=780159&page=4&pp=30 Cheers P
macnux Posted January 14, 2007 Posted January 14, 2007 Hi guys, like to seek any member's opinions here regarding thread title. If my amp specs at 75w per channel, what will the difference be if it is matched by a 50w or 120w speaker? will the 50w speaker will overloaded and incur damage in the long run? Or will the amp lack sufficient power to drive the 120w speaker? Any guidance or experience will be appreciated, cheers! In short: 1. Resistance/impedance (Ohm) more important for matching than power (watts). Yr amp will have a rated impedance (4-8 ohm usual). Speakers 4 or 6 or 8 ohm. Mismatching can lead to amp overheating. 2. Always better that rated power (watts) of amp be higher than speakers. Otherwise speakers will sound "anemic" or worse amp be driven into "clipping", again overheating or into protection mode if yr amp has this feature built in.
quickshot Posted January 14, 2007 Author Posted January 14, 2007 In short: 1. Resistance/impedance (Ohm) more important for matching than power (watts). Yr amp will have a rated impedance (4-8 ohm usual). Speakers 4 or 6 or 8 ohm. Mismatching can lead to amp overheating. Thankls guys, prompt reply as always. macnux, having said that, if the amp is rated at 8ohm and the speaker at 6ohm, i reckon the amp will kinda auto adjust to match the 6ohm speaker?
synthesis1624705793 Posted January 14, 2007 Posted January 14, 2007 Don't worry about watt rating of the speaker. Nothing bad is gonna happen under normal use. However, you need to check the speaker nominal impedance. Typically receivers are capable to handle speake with impedance rating from 6-16 ohm. Luckily, most speakers are rated about 6-8 ohm. Try to avoid 4 ohm speaker as some receiver may clip when played rather loud.
1AngMoh Posted January 20, 2007 Posted January 20, 2007 Hi guys, like to seek any member's opinions here regarding thread title. If my amp specs at 75w per channel, what will the difference be if it is matched by a 50w or 120w speaker? will the 50w speaker will overloaded and incur damage in the long run? Or will the amp lack sufficient power to drive the 120w speaker? Any guidance or experience will be appreciated, cheers! Hi Quickshot, If your amplifier is rated at 75w per channel (i assume this is RMS?) then its a good idea to look for speakers with power handling ability of 75w or greater. I don't know what amplifier you have but many lower quality amplifiers have very high total harmonic distortion and at loud volumes can clip and send out nasty spikes which in the extreme can wreck speakers. As mentioned by petetherock impedance is also important - look for speakers with 8 ohm impedance (min 6 ohms). Lower impedance speakers are much harder for your amplifier to drive. Furthermore, you should try to ensure that all of your speakers present a similar load to the amplifer. One final point, that is sensitivity. Sensitivity is measured in dB (referenced to 1w, 1m) and a typical speaker is around 90dB. Try and stay away from low sensitivity speakers (i.e. 84dB) as these need greater amplification and again, if you can, match your speaker sensitivity for all 5 (or 7) of your speakers. These are the basic rules. Good luck.
macnux Posted January 20, 2007 Posted January 20, 2007 I would actually think that a lower rated speaker and not equal wattage to the amp be a better deal. Stick to that 50W speaker. Most amps are over rated .....btw ...... ::)
1AngMoh Posted January 20, 2007 Posted January 20, 2007 I would actually think that a lower rated speaker and not equal wattage to the amp be a better deal. Stick to that 50W speaker. Most amps are over rated .....btw ...... ::) Yep, most amps are over rated are quickly overdriven and can [if appropriate clipping protection is not in-built] cause damage to speakers with low power handling capability. Some people think that high wattage speakers are more difficult to drive. How difficult a speaker is to drive is a function of its sensitivity and impedance variation over the frequency band. 50W speakers for a 75W RMS (assuming it is RMS) amplifier would not be a good recommendation.
SiriuslyCold Posted January 20, 2007 Posted January 20, 2007 I think power ratings on a speaker is meaningless. they are just guidelines at best. For example an Infinity Primus 360 is rated 10W to 200W, and there are people happily using it with low (5W per channel) SET amps. What you really need to know, is the amplifier power output enough to drive speakers of a particular sensitivity to your desired listening level (measured in db SPL) without clipping/distortion. how do we know how much power we need? use this calculator. with the Primus 360 for example: it has a sensitivity of 93db, and if your normal listening level is 80dbSPL (way loud, IMO) sitting 3m away from the speakers you only need 5 Watts. that is if you allow for 10db of headroom. Notice the calculator doesn't take into account the impedance of the speaker. how to make sure the amplifier won't run out of juice? this is where impedance ratings come into play. In our example we need 5W, and the Primus 360 nominal impedance is 8Ohms, then we need an amplifier that is rated 5W and more into 8Ohms. if you use the Primus 360 with 400W amps, can you blow the speakers if you max out the volume? maybe, but I think you wont hear it, as your hearing would have gone way before that would happen
macnux Posted January 21, 2007 Posted January 21, 2007 Yep, most amps are over rated are quickly overdriven and can [if appropriate clipping protection is not in-built] cause damage to speakers with low power handling capability. Some people think that high wattage speakers are more difficult to drive. How difficult a speaker is to drive is a function of its sensitivity and impedance variation over the frequency band. 50W speakers for a 75W RMS (assuming it is RMS) amplifier would not be a good recommendation. You are more likely to damage your speakers if your amp is driven into clipping. Go figure out your ramblings now.
petetherock Posted January 21, 2007 Posted January 21, 2007 IMO Its how hard you drive your speakers. a 50 w rated speaker will be fine with a more powerful amp eg right now I use a 60W rated bookshelf with my SR 12 which in stereo is capable of a rated 160W (proabably more in stereo) and on the odd occasion I turn it up to about 20db on the volume indicator. But if I were to drive it at THX levels, say 110db(volume) it may affect the speaker cones. In a typical flat dwelling, of less than 2000 cu.ft, at moderate levels, it quite fine. So quickshot, if you are buying something in the near future, there are more important considerations like sound quality, matching and so forth before considering something like sensitivity of the speaker, which like I said in a typical flat dwelling is not a problem for most amps of reasonable quality.
1AngMoh Posted January 21, 2007 Posted January 21, 2007 You are more likely to damage your speakers if your amp is driven into clipping. Go figure out your ramblings now. I think the point both SiriuslyCold and i both trying to make is that one can save speaker voice coils by purchasing speakers with a higher efficiency. No argument - more speakers are damaged by under-powered amplifiers driven into clipping than anything else. This does not however overlook the point that speakers are delicate things and easily become damaged by amplifiers with too much grunt. A too-powerful amplifier will also lead to sound distortion. For these reasons you need to know the power output of the amplifier you'll be using and whether your speakers will work with it. The power rating of a speaker (measured in watts) indicates how much power it can accept from an amplifier. Peak power ratings are high, but cannot be sustained without threat to the drivers. Manufacturers often give a maximum power figure only as a warning to help prevent speaker damage. The real information about a speaker's power rating is found in its watts RMS measure, meaning the maximum continuous average power it can handle. For example, a 200-watt amplifier would blow a 30 watt RMS speaker off the planet if cranked up to full power. So coming back to your 50w speaker recommendation. The problem i have with your recommendation is this - that specified 50 watts is likely to be a manufacturers peak power rating, not an RMS (or nominal) one. The peak power rating is many multiples (PMPO sometimes 10x) above what a speaker can sustain for a lenghty period. One might have a situation where that 75w RMS amplifier is driving a 10w RMS (advertised as 50w) speaker, a recipe of disaster.... So i come full circle (see my advice above) the generally accepted rule is match a 75w RMS amplifier with a 75w RMS (or greater) speaker. ok lah?
SiriuslyCold Posted January 21, 2007 Posted January 21, 2007 can someone point me to a passive speaker rated exactly x watts ( don't particularly care what x is as long as its a fixed x watts) because if there's none, then this whole discussion about 50W, or 75W or nW speakers is pointless.
petetherock Posted January 21, 2007 Posted January 21, 2007 Yeah SC! Back to quickshot's question, I think 75w per channel is enough for most speakers, ratings not withstanding, if they are used judiciously. That would apply to most flat dwellings and our ears would explode and the police would be knocking on our doors long before the speaker cones and drivers give up ;)
macnux Posted January 21, 2007 Posted January 21, 2007 I think the point both SiriuslyCold and i both trying to make is that one can save speaker voice coils by purchasing speakers with a higher efficiency. No argument - more speakers are damaged by under-powered amplifiers driven into clipping than anything else. This does not however overlook the point that speakers are delicate things and easily become damaged by amplifiers with too much grunt. A too-powerful amplifier will also lead to sound distortion. For these reasons you need to know the power output of the amplifier you'll be using and whether your speakers will work with it. The power rating of a speaker (measured in watts) indicates how much power it can accept from an amplifier. Peak power ratings are high, but cannot be sustained without threat to the drivers. Manufacturers often give a maximum power figure only as a warning to help prevent speaker damage. The real information about a speaker's power rating is found in its watts RMS measure, meaning the maximum continuous average power it can handle. For example, a 200-watt amplifier would blow a 30 watt RMS speaker off the planet if cranked up to full power. So coming back to your 50w speaker recommendation. The problem i have with your recommendation is this - that specified 50 watts is likely to be a manufacturers peak power rating, not an RMS (or nominal) one. The peak power rating is many multiples (PMPO sometimes 10x) above what a speaker can sustain for a lenghty period. One might have a situation where that 75w RMS amplifier is driving a 10w RMS (advertised as 50w) speaker, a recipe of disaster.... So i come full circle (see my advice above) the generally accepted rule is match a 75w RMS amplifier with a 75w RMS (or greater) speaker. 1. You are more likely to damage your speakers if your amp is driven into clipping. 2. So now you are saying that the amp's ratings are in RMS but speaker's rating in PMPO? Which do you actually think is more likely to be quoted in PMPO :o ? 3. Go figure out your ramblings again.
1AngMoh Posted January 21, 2007 Posted January 21, 2007 Read what i write, "one might have a situation..." Comprehension son. ::) Speakers power ratings are frequently as dubious than amplifier ratings. 50 watt speakers - bad advice, but thats ok, lets move on.
petetherock Posted January 21, 2007 Posted January 21, 2007 I think if we answer the poster's question, its a done deal :) Right bros?
macnux Posted January 21, 2007 Posted January 21, 2007 Read what i write, "one might have a situation..." Comprehension son. ::) .... Thanks, Dad ..... 8)
macnux Posted January 21, 2007 Posted January 21, 2007 .......No argument - more speakers are damaged by under-powered amplifiers driven into clipping than anything else. ...... ok lah? Ok, Dad ...... 8)
macnux Posted January 21, 2007 Posted January 21, 2007 Fr Monitor Audio's website .... "Power Handling The maximum safe power for speakers. But be aware that it's easier to damage speakers with an amp of too low power driven hard, than that with too much power." Fr KEF website .... Which Amplifiers do you recommend? We do not recommend any specific Brands or Models. However, we can give a few hints on what to look for when selecting your Amplifier/Receiver. Amplifier requirement figures (Watts) are intended only as a guide. As a general rule buy the most powerful amplifier that you can afford within the specified range and use it with great care. It is easier to damage the loudspeaker with a small amplifier driven into distortion using too much volume with bass and treble boost, than with a large amplifier which has plenty of power in reserve. If in doubt, ask your dealer.
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