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Bronze Member Username: Punjabi_supermanUnited Kingdom Post Number: 12 Registered: Aug-06 | Just brought a Denon D-M35DAB... has everything I want: DAB, WMA play back etc... the amp is 22w inro 6 ohms. I was looking at a pair of Mission M70s which are 75w into 8 ohms. So I emailed mission and they laughed. They said I need a much more powerful amp. Preferbably one with higher wattage than the speakers? So how does it work? Do I have to have more or equal watts than the speaker and match the ohms? Confused! Please help. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8973 Registered: May-04 | . They laughed?! What a bunch of snobby rats! And simple minded ones at that. It isn't about how many watts you can go buy, but rather the quality of the watts you got. The speakers are 88dB sensitivity and that should be sufficient for a reasonable quality 22 watt amplifier. You wouldn't be getting the police called to your home but you should get comfortable levels of volume. But possibly the technical folks at Mission know something they aren't interested in telling you. The speaker could present a difficult load to the amplifier and they, not knowing your amplifier well enough, assume your amplifier can't deliver the correct mix of voltage and amperage which go to make up watts. Looking at the Denon on paper, I would tend to agree. Mini-systems are not known for their overall character and quality. They use cheap output devices so they can sell for less money than "better" components. Mini-systems are often paired with speakers which are specifically designed to make the most of the amplifier provided by the manufacturer. Swapping speakers normally isn't the best route to upgrading your system once you've committed to a mini-system. Why do you want to change speakers if you like what you have? More expensive speakers don't always mean better sound. . |
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Gold Member Username: Frank_abelaBerkshire UK Post Number: 1578 Registered: Sep-04 | Hello G, Jan is on the money with the information I'm afraid. The way Denon specify the amp's power output is quite restrictive. It's 22w/ch/1khz/6 ohms. In other words for a signal of 1khz specifically, the maximum rated output is 22 watts into a 6 ohm load. Typically when an amp is rated this way, its power output drops into the full frequency range that we like to hear (typically rated as 20hz - 20khz). Also, the output into 8 ohms (a more typical impedance for a speaker) would also cause the output rating to drop. The matching SC-M73 speakers are rated as being a 6-ohm load (which matches nicely) and they can take 60W apparently. they do not mention how efficient the speakers are. Efficiency is a sign of how much sound a speaker will produce for a given watt of power. It's likely the SC-M73s are fairly efficient in order to take it easy on the amplifier for which they've been designed. If you would rather not buy the Denon speakers since they aren't a particularly highly recommended item, your best bet is to look for speakers which are of above average efficiency. This will usually be accompanied by a benign impedance load of 8 ohms. An average speaker is around 88db/w/m. Look for something above 90db/w/m, always maintaining the 8 ohm impedance, and you shouild be in business. 92 or 94 db will be driven very happily by 22 watts. The problem will be finding a speaker like this for reasonable money. All that said, Onkyo make a similar unit called the CR-505DAB which is rated at 25 watts into 4 ohms. This means it's probably about as powerful as your Denon unit. I have had a lot of success with the Onkyo driving a pair of B&W DM600 speakers. It's a fine match and would probably be a good match with the Denon. Worth a look. Regards, Frank. |
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Bronze Member Username: Punjabi_supermanUnited Kingdom Post Number: 13 Registered: Aug-06 | Thank you guys. I really appreciate it. So I do not need to match the ohms? Rather... look for a higher wattage, ohm and with high dB (sensitivity) rating? Makes sense but I always thought the amp had to be more powerful than the speakers. I guess it wont damage anything if it is played responsibily. The system has a Burr Brown DACS. I heard it with the Denon speakers and it did not sound too impressive. I have arranged an appointment to hear those B&Ws suggested. Thanks again |
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Bronze Member Username: Punjabi_supermanUnited Kingdom Post Number: 14 Registered: Aug-06 | So am I right in guessing that 22w into 6 ohms would be 44w into 3 ohms? Or am I getting ahead of myself? |
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Bronze Member Username: Philipt95148Post Number: 18 Registered: Jun-06 | Jan, In another forum for Monitor Audio RS6 speakers, there are people reporting better bass response by using more powerful amps, like Parasound Halo Amp at 250wpc. This is way above the max for the RS6. Could you enlighten us on how this is the way it is? Thanks Philip |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8980 Registered: May-04 | . PT - Your statement covers a lot of ground. "Watts" are not what's important. The amplifier has to deal with the load the speaker places in the circuit loop formed by the amp's output devices, flowing through the speaker and back into the amplifier. From the "+" of the amplifier's outputs, the speaker is placed within the circuit (loop) which comes back around to the "-" of the amplifier. At some points the amplifier is driving the speaker and, at others, the speaker is driving the amplifier. Along the way, resistors, capacitors and inductors are inserted in the circuit. They all affect how the circuit operates and ultimately sounds. Without the speaker in the circuit, the amplifier won't work. There must be a load for any energy to travel through or no work can be accomplished. With the speaker in the circuit, the amplifier can have an easy or difficult time accomplishing its work (or anything in between those extremes). The "load" is never constant and changes with each amplifier/speaker circuit. With each combination the requirements change with frequency and loudness levels (both constant and dynamic) and time. Therefore looking at static bits of information on a piece of paper won't tell you much about how a speaker will mate with an amplifier or vice versa. There are basic electrical functions which can help you guess whether an amplifier is well suited for a particular speaker but exceptions are often found when synergistic combinations mate. Since I don't have a clue what "better bass response" amounts to for anyone else, I can't comment on that subject. If the speaker is not an easy load for an amplifier (which isn't determined by price, size, or size/number of drivers), a better built amplifier with any amount of clean, well controlled wattage will probably sound better with that speaker. Assuming the two units mate well. Large amps don't guarantee good sound any more than small amps preclude good sound. (I have a six watt amplifier which drives some of my speakers quite well and does a less than great job on other speakers I own.) It is the combination of the correct amp with the right speakers which is important. There are sufficient numbers of 2 1/2 watt amplifiers which are giving the owners substantial pleasure when paired with the correct speaker. There are sufficient numbers of 200 watt amplifiers I wouldn't care to listen through for any amount of time. Most speakers can handle clean power well beyond their "max" rating in most cases (since those are static ratings and they mean nothing in a real world sense) and they can easily be "blown up" by amplifiers with too little power. ("Blown up" is relative to what the amplifier accomplishes with the speaker in the circuit.) I have to repeat, it is the correct combination which is important. Right combination = good sound. Bad combination = the obvious alternate extreme. It is not any given number on either piece of equipment you should look at. Forget about almost all the specs. I have previously stated on this forum, the only important specs you need to consider are the height, width, depth and weight of any component you are considering. Beyond that the basic specs provided by the manufacturer, and most specs given in test bench measurements, are insufficient to determine very much about any component on the market. While you should understand the basic electronics which will likely make a good combination work, a good dealer should be able to assist you in mating amplifiers and speaker. If they can't or won't, find a better dealer, not a better amplifier. Also, refer to Frank's comment about the way measurements are taken and given for various types of audio products. Most specs say nothing to not enough. I know it's confusing at times. But the basic concepts are laid out in reviews and measurements taken by magazines such as Stereophile. Read how an amplifier will probably react to difficult loads and how difficult any given speaker is to drive. Remember all these measurements are typically taken under conditions which do not resemble how the amplifier and speakers are actually expected to work within a music system. This should at least get you on your way to understanding what is important when judging a system combination by judging numbers alone. After you've mated the two pieces electrically, then you can concentrate on whether they sound good when paired together. . |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8981 Registered: May-04 | . G - You're not only getting ahead of yourself, you're going to blow something up with that logic. |
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Bronze Member Username: Philipt95148Post Number: 19 Registered: Jun-06 | Jan, thanks for the informative explanation of speakers and amps interaction. I never thought of the +, - outputs of the amp this way, it does make perfect sense once you know it though. I agree with you that "better bass response" is subjective, I was merely asking about the wattage of an amp relative to the max rating of a speaker and you have explained it now. Given that understanding, is it fair to say that more watts would drive the bass cones of a speaker more and give the listener the impression of "better bass"? Is this why in an HT environment, a bigger wattage amp is always used? To provide all the explosions, car chases, etc. necessary to reproduce a theater experience? Of course, quality is not the question here, just volume or quantity. |
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Silver Member Username: RavbainsMelbourneAustralia Post Number: 237 Registered: Mar-06 | Hi, Denon make a dedicated pair of speakers, designed to mate specifically with the Denon D-M35DAB unit. I believe Mission actually help Denon with the engineering of these speakers!!!! http://www.denon.co.uk/site/frames_main.php?main=prod&ver=&MID=3&sub=3&action=de tail&Pid=224 I believe the part number of these speakers is listed in the link above. Is there any reason why these dedicated speakers are not suitable? I would believe that using anything else would be being overly ambitious, most mini systems use a chip amp as their output stage, similar to those used in car stereo head units. cheers Rav |
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Silver Member Username: RavbainsMelbourneAustralia Post Number: 238 Registered: Mar-06 | Ooops! did not note that you did not actually like the Denon speakers!! Pardon me. Monitor Audio make some nice speakers which are an easy load and should work well with a mini-system. http://www.monitoraudio.com/products/radius/index.htm cheers Rav |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8982 Registered: May-04 | . The overall volume of the system is dependent on several factors. The most important of all those facors is the efficiency, sometimes referred to as sensitivity, of the speaker system. Keep in mind it requires twice the wattage to raise the SPL limits of the system by three decibels. And that doubling of power is constant as the wattage increases. Three decibels is about where the human ear can reliably detect a difference in volume between two music signals to say one is louder than the other. (This is not the same as comparing components at similar volumes where the ear will almost always pick the louder system as better even [even if you are comparing identical systems] when the difference is a mere 1/2 dB.) The speaker is the final determinant in the equation when deciding SPL potential. If we take an average speaker which plays at 88dB with one watt (2.83 volts) into the system, it would require only one additional watt to raise that system potential three decibels to 91dB. And it would require an additional two watts to get to 95dB. However, when we get to the range of 50 watts, it would require an additional 50 watts to gain the same three decibels. After that it would always require doubling the wattage to gain three dB. Buying wattage begins to get expensive as you get to the point where you always have to double the wattage to gain that same three decibels. 500 watts has to increase to 1,000 watts and so on. On the other hand buying a more sensitive speaker is not necessarily a more expensive proposition. If you choose a speaker with 91dB sensitivity, you have made the same increases in system SPL levels as you would by buying the 1,000 watt amplifier rather than the 500 watt amplifier. If you had purchased the speaker with 100dB sensitivity, you can do the math to determine how loud the system will play with "X" amount of wattage compared to that average 88dB speaker system. (http://www.myhometheater.homestead.com/splcalculator.html) The drawback to this solution is normally considered the uneven frequency response and sometimes higher distortion products which accompany highly efficient speakers. Today's speakers are, on the whole, more efficient than what the industry was selling two decades ago. However, the way the industry has gained that additional sensitivity is not by making the drivers more efficient but by placing them in different enclosures. Vented enclosures rule the market today where sealed boxes were the ubiquitous choice in the 1970's and 80's. A vented box is typically three dB more "efficient" than a sealed box speaker system. The trade offs are evident when you listen to the sound of both types of speakers, but many people will give up better bass control to gain the additional SPL's. When vented boxes are all you hear, you eventually get to the point where you don't even know what the better bass response of a sealed box sounds like. Unless you listen to live music as a reference. That gets me into another of my positions which isn't required for this discussion. Selling wattage is simpler than making speakers more efficient. The great horsepower race of the 1970's cemented in many buyer's minds the idea that power was the determining factor in sound systems. Just as buying higher horsepower in an automobile might easily ignore some important values an automobile must possess (handling, torque, gear ratios, etc.), so does it affect sound systems. Higher output amplifiers can ignore some of the basic functions of an amplifier when designing for on-paper specs is what becomes important. Selling the specs and/or selling the "faceplate" (features/remote control) has become common in most low end audio shops. If you've ever been in a high end audio shop and heard the sales staff recommend buying the amplifier with the least amount of watts and the fewest buttons and knobs, you've probably been in a situation where the client didn't require anything other than good sound. Simplicity and low wattage are not guaranteees of good sound but they will often go a long way toward eliminating many of the problems which come between you and the sound of the original recording. There are different attitudes toward buying any product where a subjective judgement makes the decision. In audio there are a number of listeners who would rather have that low wattage amplifier without buttons or knobs because they feel it sounds the best. To them that approach represents the simplest, straightest path bewteen the source and the speakers. If the amplifier has been designed and constructed properly, and paired with the proper speakers, that very well might be the best solution. There is no right or wrong way to buy an audio ssyetm. As you spend time and listen to music, you will develop your own opinions regarding what is important to you and what is not. Whether power is important to you will depend on several factors. Not the least of which will be what speakers you own. . |
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Bronze Member Username: PointeOttawaCanada Post Number: 38 Registered: Jun-06 | G, it really depends; what are you going for? I'm surprised I'm the first one to ask. Usually the other guys above break out this question on the newbies... I first started building my system with an old minisystem as my power source. I bought speakers that generally sounded good, and sounded very good with the power I figured I would eventually buy. This path worked for me. If you see the Denon D-M35DAB as one step on your way to a much different end, you could look at a range of speakers, keeping in mind where you might want to end up as your budget increases. I say this on the assumption that the sound quality will be similar to other mini systems in its class (not so great), as I haven't heard this piece. Otherwise, the matching speakers may be a very good purchase. If you think this Denon will be all you ever need, keep it simple. Buy the matching set. They were designed to go together. |