Power loss with speakers

RosieGlow

Novice Member
Hi guys, I hope someone can help me here. I have a small 35w stereo and use my old 90s Aiwa speakers with them which I really like but wanted to replace. They are bulky so I got smaller bookshelf speakers thinking I would eventually build an entertainment system by gradually adding to it. The Aiwa speaker spec are 6 ohms with 40 watt max power. My new speakers are 8 ohms with 76watt max power. I tried them in my stereo but they were very quiet compared with the Aiwas and needed the volume turned up a lot to get anywhere near the old sound. I have disconnected them so as not to damage them. I guess I may be needing a powered amp but to be honest I get totally bamboozled with the jargon. Can anyone explain to me in layman's terms what is happening here and what I should do. I would appreciate some advice. Thank you very much!
 

dogfonos

Well-known Member
Difficult to be certain what's going on here. Could you provide more details (ideally, make and model number) on both the new speakers and the "35W stereo" you use?

If (big if) all the gear is working correctly, then it could be the case that your new speakers are far less efficient (i.e. produce less sound output for the same power fed to them) than the old Aiwa speakers. I'm surprised you find such a difference in volume levels between the old and new speakers using the same volume control setting on the amp but then again, by and large, big speakers are more efficient than small ones (there are exceptions though) and it is certainly possible that the difference in the speakers' efficiency is huge.

I suspect the "35W stereo" may actually output less power than the headline figure suggests. For instance, is there an RMS figure for power output into 8 Ohms, both channels driven? Or is the 35W stated as PMPO? An RMS figure would give a clear indicator of true power output. If this "35W stereo" turns out to have something like 10W RMS per channel into 8 Ohms and the new speakers are pretty inefficient (and/or difficult to drive), then I can imagine maximum volume would be low - might also get some distortion if driven to high-ish volumes.

My new speakers are 8 ohms with 76watt max power
This seems a little strange. Max. power ratings for a speaker are not a precise science so for a manufacturer to state the very specific figure of 76W seems odd to me. IME, most speakers have an indicated power handling rating rounded to the nearest 5 or 10 Watts.
 

RosieGlow

Novice Member
Hi Dogfonos, thanks for replying. My stereo is just a small Wharfedale model number NE-571USB which operates without a separate amp. The speakers that I ordered were Auna 300 bookshelf speakers but I am going to send them back. I was going to order Wharfedale Diamond 9.1s as they seem to have excellent reviews but I wasn't sure about the bi-wire and also thought that they may be too powerful for my stereo (from what I have read online but not very sure). My stereo instruction manual only says that it is a 35watt power stereo and there is no other info on the stereo itself. My old Aiwa speakers state that they have a music power output of 40watts but I was unsure how that translates to RMS or Max power. Are there any bookshelf speakers that you would recommend that would work well on this Wharfedale NE-571USB. I don't want to buy a new stereo, I would consider buying an amplifier in order to make an entertainment unit but for the moment I just want a decent pair of small speakers. Thanks for your advice. RG
 

dogfonos

Well-known Member
Wharfedale NE 571 USB MP3 - Product review and consumer advice

Is this the unit? If so, it's got even less power than I suggested in post#2. We're talking about 2 to 4 Watts by the look of it. As a guide, a typical dirt-cheap mini-amp would output around 8 Watts per channel into 8 Ohms (although considerably more power is often misleadingly claimed). These amps are just about able to drive speakers like the Wharfedale 9.1 albeit with limited maximum volume and increased distortion as the volume rises. I would think that around 20 Watts RMS per channel into 8 Ohms would be the absolute minimum power I would suggest for a budget hifi system (oddly, there are esoteric exceptions).

The amplifier contained within your Wharfedale unit is unlikely to be capable of powering small hifi speakers to a reasonable, undistorted volume. The stated sensitivity of the Auna 300(SF?) speakers are typical of it's type - around 87dB - although I suspect the figure may be even lower. I'm afraid the Wharfedale Diamond 9.1 won't be suitable either. If you're determined to retain the Wharfedale unit, better stick with non-hifi speakers (probably like your old Awia's). By that I mean single drive unit (i.e. no energy sapping crossovers) and high efficiency/sensitivity to make the most of the very, very, very limited power available. That said, I don't even know if these sort of speakers even state an efficiency/sensitivity figure but if they do, look for 93dB+ (the higher the better). Most speakers of this type are supplied with cheap music playing systems and I'm afraid I have no idea where you might purchase a pair on their own.
 

dogfonos

Well-known Member
Thinking about it...

You were considering the purchase of Wharfedale Diamond 9.1 speakers, right? These currently sell for around £100. Why not ditch the Wharfedale NE571 USB MP3 and buy a cheap CD/DVD player together with powered speakers (i.e. speakers with in-built amplifiers)? You can do that for a similar outlay and end up with something with more power and, probably, better audio quality too. Many big-brand, new CD/DVD players without HDMI are available for under £30 - just make sure it has RCA/phono output sockets for audio connection to the powered speakers such as this one from LG:

NEW LG DP132 Multi Region DVD PLAYER - Multi-Format Compact Size DVD Player

(may be available cheaper elsewhere)

and partner it with:

M-Audio AV32 Active Powered Studio Desktop Reference Monitor Speakers PAIR | eBay
or
Alesis Elevate 4
or Tascam VL-S3 active monitors for sale | Bax Music
or slightly over budget:
M-Audio AV42 Active Speakers Pair

(may all be available cheaper elsewhere)

Or even buy a new, half-decent, big-brand mini-system for about £100.

I have to say that the LG DP132 with the M-Audio AV42 would be a very tidy budget system.
 

RosieGlow

Novice Member
Thanks again for the reply. Its not a very powerful system at all then is it! What I like is that it plays lots of different media. I was considering powered speakers and I have had a look at a few. I'll have a look at some of your suggestions tomorrow but I appreciate you taking the time to reply. Keep you posted.
 

dogfonos

Well-known Member
I was considering powered speakers and I have had a look at a few.

Just in case of any misunderstanding...

Not much info. about the Wharfedale NE 571 USB available online. Looking at the limited info. I've found, I can't see a way of connecting powered speakers to your Wharfedale NE 571 USB unit. So, unless anyone knows different, going down the powered speakers route will require different 'source' equipment (such as that suggested - though many other sources will be suitable).

NB 'Source' equipment is that which reads the media.
 

RosieGlow

Novice Member
Would connecting via the headphone out be a bad idea? I know folk do it with phones and TVs. . . ??? My DVD player plays cds and has RCA out so I could use that for cds. I was also thinking about connecting it direct to my tv as I often send music to that. Only thing is that has an optical out for sound so I would maybe have to connect that with a jack via the headphone out too. . . any thoughts?

Cheers
 

dogfonos

Well-known Member
Would connecting via the headphone out be a bad idea?

You could almost certainly connect powered speakers to the headphone outlet of the Wharfedale and to the TV's headphone outlet too. I say 'almost' because there are rare cases where the output from the headphone socket isn't sufficient to drive the (generally) high impedance input of powered speakers (and amplifiers) so volume won't go loud enough. Also, you'll probably not achieve the best audio quality though I don't see you have much choice if you intend to use the Wharfedale unit as the source. Using the headphone socket has one advantage in that you should be able to control the speakers' volume from the source unit's volume control(s) rather than the speakers' volume control (though you can do either or both).

Like I say, not much info online about the NE 571 USB MP3 so correct me if I'm wrong but doesn't this unit just play CD's and DVD's and have a USB interface?. You mention another DVD/CD player? And the TV with optical output and headphone socket? Maybe a good point in time to reconsider the entire sound system?
 

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