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New member Username: HifinovicePost Number: 1 Registered: Sep-11 | Hi, I am about to buy a Monitor RX6 pair of speakers, knowing that I may have to upgrade the amp. But will the amp be able to service the speakers, or am I making a ghastly mistake? in ignorance... John |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16803 Registered: May-04 | . What concerns do you have? What speakers are you replacing? What sort of music do you favor and how loud? |
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New member Username: HifinovicePost Number: 2 Registered: Sep-11 | Thanks Jan, concerns are firstly is there enough power (30W per channel on the NAD) and will this make the RX6 speakers under perform; and secondly I have read various disquieting comments about some amps not working with some speakers. So it is a feeling of seeking reassurance I suppose. I had Heybrook HB6 speakers (old!) that have finally gone south and I like listening mostly to rock or indie music, with some non trashy pop, and classical music (other than opera) - so fairly catholic. John |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16804 Registered: May-04 | . The first flag your post presents is, "I had Heybrook HB6 speakers (old!) that have finally gone south". Why did they fail? If you were asking too much in the way of volume from the speakers, then the RX6's still might be problematic. If you'll cruise through the archives of the forum, you'll find that speakers are the most vital factor in how loud a system can go. The specificiation you need to pay heed to is stated as either "sensitivity" or "efficiency". It will provide a number rated in (output) decibels along with a stated amount of input power to the speaker. The input wattage should be the equivalent of one watt (stated either as "one watt" or "2.83 volts" and measured at one meter distance) though manufacturers have been known to fudge this number to make their specs look better than the speaker actually manages to be. Therefore, it's not completely unusual for a speaker rated at 87dB to subjectively play louder than another speaker rated at 90dB. It is virtually impossible, however, for a speaker rated at 84dB to play louder than that 90dB speaker. (For the record, each time you add an additional 3dB to the output specification of the speaker, you have done the same thing - essentially - as doubling the output power of the amplifier taking a 30 watt amplifier and providing a virtual power of a 60 watt amplifier. [There's more to all this than just watts and sensitivity but this is the best place to start when determining the successful pairing of amp and speakers.] Put another way, increasing the speaker's output by 3dB would halve the amount of power required from the amplifier to reach a comfortable listening level. The issue then is what you consider to be "comfortable". ) If you want volume - and most especially if you want volume and lots of bass - you want a speaker with a sensitivity spec as high as possible. The higher the speaker outputs with one watt input, the louder it will play with, say, 30 watts. There are easy tables available to indicate approximately how loud any speaker will play with "X" amount of watts available but the basic thing to remember is, the higher and higher the sensitivity, the less watts you'll need to play louder and louder. So speaker sensitivity and not amplifier watts are what's most important to gaining high volume levels. However, that's not the entire story of how a speaker relates to an amplifier. More importantly and seldom mentioned by any speaker manufacturer is the impedance range and the electrical phase angle of the speaker as a complete system of electrical components. Monitor Audio - that is the line we're discussing, right? - states the RX6 has a nominal impedance of 6 Ohms which is acceptable for most solid state amplifiers. (They do not provide a "lowest impedance point" spec and that could be a sticking point though MA's are generally a less problematic speaker in this regard.) What isn't provided at all is a spec for the difficulty presented by the electrical components as they make up the "electrical phase angle" of the system. If we assume the RX6 has similar characteristics to the majority of MA's mid-priced ines, then the RX6 should be a relatively easy load on most amplifiers and suitable for most "budget" high end amplifiers like the NAD. (You can find several threads which discuss impedance and phase angle in the archives of the "Speakers" section of this forum. You can then call MA and ask for a clarification of the phase angle of the RX6 to arrive at a better idea of just how well the speakers might pair with any amplifier.) The issue then would be one of volume requirements I suspect. If you blew out the tweeters on the Heybrooks, then you were likely asking too much of the system and you'll have to adopt a different approach to how you use the RX6's. The age of the speaker means nothing to why they might be damaged when you are asking the system to play at levels where the amplifier is clipped ( http://search.yahoo.com/search?ei=utf-8&fr=slv8-hptb5&p=causes%20of%20amplifier% 20clipping&type=. If the woofer was damaged, then you'll need to think about the amount of bass you require and how best to go about achieving that end. The rule of thumb is "when you hear distortion, turn down the amplifier". This is difficult for many novices to learn as there is a degree of intentional distortion built into the music they prefer. A general rule would be to pay attention to the volume control and how the system operates. At levels beneath clipping of the amplifier's power outputs, advancing the volume control will result in noticeably even increases in output level. As the amplifier reaches it limits advancing the vc no longer produces the same increase in volume and, if you continue to advance the vc, no increase in volume occurs, only more clipped distortion from the amplifier. So, if you know nothing else about distortion from the amplifier, when the vc no longer produces a noticeably louder volume, you've already overshot the limits of the amplifier and need to turn down the volume or risk damage. Increasing the amount of bass in the music (or by increasing the bass tone control) will lower the volume level where excessive clipping occurs as dynamic bass output eats up power requirements. Therefore, the basic answer to your question would be that the NAD is well suited to the RX6's if you pay attention to the volume levels and the distortion produced as you raise those levels. Should you buy a 60 watt NAD, you'll find there isn't much difference in the total volume potential of the system - barely if at all noticeable in fact. You would need to buy upwards of 200-250 watts to achieve a truly noticeable difference in peak volume levels or you would need to find a speaker with a substantially higher sensitivity spec. That said, 250 watts of distorted rock music into the RX6 would probably damage the speaker anyway. Use the 3130 amp and RX6 speakers together and you should find good results if you don't ask something neither can manage. . |
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New member Username: HifinovicePost Number: 3 Registered: Sep-11 | Jan, thanks so much for the informative response. I can't know for certain what happened to my previous speakers, but on one of them, one of the parts was moving in and out more than on the other, that obviuosly indicated something was wrong, and they ceased working properly a few weeks ago. However I have no knowledge of the component parts so can go no further than that. Anyway, I had over 30 years of use from the Heybrooks, so we had a happy time together. MA RX6 it is and I hope the amp is up to it! I can't think that I play music louder than usual, but shall see how it goes. Thanks a lot. John |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16806 Registered: May-04 | . " ... one of the parts was moving in and out more than on the other, that obviuosly indicated something was wrong ... " This could indicate a problem with the amplifier. Your amp is going on 30 years old and it might be time for a few repairs. A loudspeaker can do nothing to make parts move on their own. The amp must drive the speaker components and about the only driver large enough, with excursions of sufficient length, for you to notice the degree of motion would be the low frequency woofer. You make no mention of what input was playing when the woofer was doing this long throw action but, if it was a turntable, we have one thing to discuss. If, on the other hand, the source was anything other than a phono input, there is a good likelyhood the amp might have a bad capacitor. Further, if the driver stopped working suddenly, then there might be some DC leakage into the amplifier outputs. Should that be the case, trying to operate the new speakers with a malfunctioning amplifier will result in damage to the new speakers. Do you have access to anyone who could check the "DC offset" of the amplifier before you connect the new speakers? . |
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New member Username: HifinovicePost Number: 4 Registered: Sep-11 | Jan, I have fixed up the RX6 speakers to the amp now and though everything was perfect to begin with, I have noticed a couple of worrying things. 1) the R speaker seemed to hiss when I turned the volume up 2) the sound has started occasionally going in and out of focus (up and down in volume and losing the sound almost). I've stopped using the system, and I'll get the amp repaired. I hope the amp isn't damaged irreparably. The 30W amp though seems easily loud enough. Even at 20% volume it's loud, and I really wouldn't want to increase it beyond that. I do hope I haven't just thrown away £800......... Thanks. John |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 16813 Registered: May-04 | . Ask the repair shop to give you an estimate of the total repair costs before having any work performed. This will typically run about $40-50. If you decide to have the unit repaired, the money is applied to the repairs. If you decide the unit is no longer of sufficient value to warrant repairs - due to its age or the extent of the problems - you'll be out minimal funds. . |
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New member Username: HifinovicePost Number: 5 Registered: Sep-11 | Jan, firstly if this is getting boring for you, no worries. I am grateful already for what you've said. But I am going to buy another amp I think. My old amp is over 20 years old, and I think it's false economy to repair an amp that is a bit low powered, and old. Any ideas within the same sort of price range, say £500 - £800 ($750 - $1200)? To set my mind at rest (hopefully!) is it really likely that I have damaged the speakers with an old amp? I note your comments about DC leakage, but the amp never stopped working, just made the hissing unfocused sounds I emntioned before. Are they really that sensitive? (Not really sure what you can say here, I admit!) Thanks. John |