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Thread ID: 145518	2017-11-22 03:35:00	Panasonic stereo - question about speakers	BBCmicro (15761)	PC World Chat

Post ID	Timestamp	Content	User
1442366	2017-11-22 03:35:00	We recently bought a Panasonic stereo-plus-speakers SC-UX100. The sound quality incl the Panasonic speakers is quite good. But it is not up to the standard of my previous speakers - B&W DM4 - which we bought in the 1970s for about $800. I can adjust the Panasonic equalisation to make it sound OK but it needs constant readjustment depending on the material. The old speakers used to sound good on everything I would like to try my old speakers on the new system but the manual seems to discourage that (see attached pics). So what do you think - what is the likelihood of a meltdown? The new speakers are 4 ohm, the old ones 8 ohm but I don't think that difference will matter at the low powers we use. There's no bling (RGB) in the new speakers. I'm just worried that some component of modern speakers might have changed in 40 years	BBCmicro (15761)
1442367	2017-11-22 03:47:00	Shouldnt be an issue . Just plug them in & try. The panasonic look cheap & nasty :)	1101 (13337)
1442368	2017-11-22 03:55:00	8 ohm speakers will draw less power than 4 ohm ones so there is no danger of overloading the system. You will probably have to turn the volume up more to get the same sound level as the 4 ohm speakers.	Terry Porritt (14)
1442369	2017-11-22 07:04:00	Thank you Terry - I think you have indirectly solved the problem I agree that with 8 ohm speakers we'd have to turn the volume up. Which means if the 4 ohm speakers were used on an amplifier expecting 8 ohm speakers, we'd have to turn the volume down. The amplifier could deliver twice the power and blow the speakers So Panasonic are trying to protect the speakers, not the amplifier. They don't want the customer using the speakers on a (conventional?) 8 ohm amplifier, blowing them up then making a claim on Panasonic And when I re-read the Panasonic warnings that seems to be the case. "Use the speakers only with the recommended system" is a statement about the speakers not the Panasonic amplifier I feel completely happy about using my 8 ohm speakers with the Panasonic amplifier. So thanks again Terry :thanks	BBCmicro (15761)
1442370	2017-11-22 07:30:00	You should be ok, and the B&W speakers are most likely far better quality. Conversely, using 4 ohm speakers with an amplifier designed only for 8 ohms may not only overload the speakers somewhat, but may also overload the amplifier a bit if the volume was turned right up.	Terry Porritt (14)
1442371	2017-11-22 18:13:00	We recently bought a Panasonic stereo-plus-speakers SC-UX100. The sound quality incl the Panasonic speakers is quite good. But it is not up to the standard of my previous speakers - B&W DM4 - which we bought in the 1970s for about $800. I would like to try my old speakers on the new system but the manual seems to discourage that (see attached pics). hah, of course they discourage it. 1)In case of lack of knowledge and doing something dodgy I guess although it's unlikely to cause too much excitement I've done similar and destroyed speakers, but there was no fires, electrocutions or anything, just sad speaker remains 2)They want you to buy theirs, not use some already in existence ones.	pctek (84)
1442372	2017-11-22 20:14:00	you cant make wild assumptions about 8 ohms drawing less power than 4 ohm speakers In the real world nothing is that simple. if your 4 ohm speakers are more efficient than the 8ohm speakers, you will need more power on the 8ohms speakers to get the same volume real world: some speakers have an efficiency rating of 90db/W or less , some are rated at 100db/W . Thats a huuuuge differnence in vol for the same power at low volume levels , its not really going to matter anyway .	1101 (13337)
1442373	2017-11-22 22:03:00	you cant make wild assumptions about 8 ohms drawing less power than 4 ohm speakers In the real world nothing is that simple. if your 4 ohm speakers are more efficient than the 8ohm speakers, you will need more power on the 8ohms speakers to get the same volume real world: some speakers have an efficiency rating of 90db/W or less , some are rated at 100db/W . Thats a huuuuge differnence in vol for the same power at low volume levels , its not really going to matter anyway . Less than 11?	Whenu (9358)
1442374	2017-11-23 01:48:00	you cant make wild assumptions about 8 ohms drawing less power than 4 ohm speakers In the real world nothing is that simple. if your 4 ohm speakers are more efficient than the 8ohm speakers, you will need more power on the 8ohms speakers to get the same volume real world: some speakers have an efficiency rating of 90db/W or less , some are rated at 100db/W . Thats a huuuuge differnence in vol for the same power at low volume levels , its not really going to matter anyway . No wild assumptions at all :) You have introduced a new parameter into the discussion, speaker system efficiency, I don't disagree with what you say but it is a red herring, akin to saying that someone hard of hearing has to turn the volume up and hence the speakers draw more power. The salient point relating to the original question is that 8 ohm speakers connected to a 4 ohm amplifier are not going to cause damage when the volume is turned up to maximum. Whereas 4 ohm speakers connected to an 8 ohm amplifier could cause strife if the volume is turned up to maximum. The amplifier does not know what the speaker efficiency is, all it sees is an impedance, and in general all things being equal with the same volume control setting, 8 ohms will draw less current than 4 ohms. Speaker efficiency is something perceived by the listener who will adjust the volume control accordingly. Now there could be an interesting discussion on the pros and cons of a ported bass reflex enclosure versus a non ported highly damped enclosure......................................... ..........:devil	Terry Porritt (14)
1442375	2017-11-23 03:14:00	Terry beat me to it, but I don't think it's totally a red herring. Below half power 1101 is correct and the more efficient speaker will use less power at any given volume (as measured by your ears not the dial on the amp). If the efficiency is similar then you will likely lose a bit of maximum volume with the 8 ohm speakers, but on the plus side you will stress the amp less and should get less distortion too. If you go by the position on the volume knob rather than perceived volume then the lower impedance will always use more power and give more volume for the same efficiency. So I guess I'm agreeing with both of you, probably shouldn't have bothered :) Better amps often have an impedance selector or a matching circuit, cheaper combo packages tend to be designed for a single speaker impedance. There may technically be some effect from an impedance mismatch but it's not something you are likely to actually notice. I do something similar with a small Sony stereo I've had for years, it's own speakers are ok but a bit "boomy" and lacking in treble so I use a pair of old wharfedale surround speakers which aren't really intended for that type of use but still sound way better. There's a difference in impedance there too but it's never been an issue. How often do you actually crank a stereo to full volume? I think the Sony speakers are 4 ohm and the wharfedales 6 ohm, just to be different (4 and 8 were always the common standards) but you don't actually notice a lot of difference between them in terms of volume.	dugimodo (138)
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