Bus_Boy Posted February 8, 2011 Posted February 8, 2011 (edited) Sooo i've decided to bite the bulllet and buy a set of speakers that actually work I've allocated myself $500, and no more. So the 2 usual suspects are on the cards, the Diamond 9.1's, and the Usher S520. It will cost me $325 to get the 9.1's to the door. The S520 will cost slightly more. However i can pick up a pair of Diamond 9.5's, new, for $499. They are a silver finish, my least prefferable colour, but sound over appearance i'm sure i could live with them. http://www.wharfedale.co.uk/Products/Product/tabid/78/PID/10/CID/51/language/en-GB/Default.aspx Originally floor standers were not considered given the small budget. But at the price, they must be considered. My concern though is the relatively low sensitivity of the Wharfedales. My Marantz 5.1 amp is 50w per channel. I know how the smaller 9.1 performs with similiar power, so if i went that route i atleast know what to expect. The S520 also has a similiar sensitivity rating. But the 9.5's have a 6.5'' midrange, along with a 6.5'' bass driver. Im thinking that's too many drivers, too much power handling, and not enough grunt from my Marantz. Wharfedale states input power of 30-150W. If 30 is the minimuim, then 50W isn't offering much.... Am i right ? Edited February 8, 2011 by Bus_Boy
bhobba Posted February 8, 2011 Posted February 8, 2011 Check out: http://myhometheater.homestead.com/splcalculator.html http://www.ellisaudio.com/wattsratings.htm Basically the bottom line is: 'Given 85db/watt speakers, a good El34 push pull (about 35wpc) or a good 60wpc stereo amplifier will get the job done with more than enough power. It is also why a good 10 watts of push pull can sound incredibly good at normal listening levels. Most often we listen to 2-3 watts of nominal power through our speakers. The peaks are obviously higher (5x - 10x nominal), and some headroom is needed. ' Since your speakers are 88db you should have no problems - that extra 3db means they are twice as sensitive than 85db speakers so 15W valve and 30 transistor would be OK. Thanks Bill
supergroove Posted February 8, 2011 Posted February 8, 2011 you can get Wharfedale 10.1 for 385AU free delivery in every finish, if your looking at 9.1's at 325 may be worth the extra. No affiliation with anyone. I almost went down that road, but got Monitor Audio Bx2 for 500 instead, and happy with those, just another option.
k-k-k-kenny Posted February 8, 2011 Posted February 8, 2011 Bill That spl calculator link is great - thanks I can only get to 110dB - boo hoo - I wanted to make my ears bleed without sitting closer. And if I went and got one of Earl's 2A3 amps, I'd still have 104, which might be enough. Except the bride would notice, I'm sure ...
Batty Posted February 8, 2011 Posted February 8, 2011 I would suggest that 50 watts is plenty, I use a mere 20 watts into 86dB 1w/1m bookshelves on my PC setup and is certainly enough for me sat approx 4ft from the speakers. Used the calculator for my main system it recons 112dB max.
Cyber_Murphy Posted February 8, 2011 Posted February 8, 2011 (edited) you can get Wharfedale 10.1 for 385AU free delivery in every finish Where from supergroove?? I'm tossing up between them (10.1's), S520's or LSK M6's.. Cheers.. Edit: located at CSAV Edited February 8, 2011 by Cyber_Murphy
davewantsmoore Posted February 9, 2011 Posted February 9, 2011 Watts is only relevant for your SPL goals. The load your amp can drive is what will affect the sound. The Wharfedales are all "nominal" 6 ohm ... Their website doesn't offer impedance graphs, but you could guess there's going to be a fair dip below 6. Does you amp have a switch for 4ohm?, or does the manual say anything about a rating?
Paul Spencer Posted February 9, 2011 Posted February 9, 2011 I tried the calculator and got 130 db! (but I cheated ... I only get that with the tweeter) ... 111 for the mids, which I think is very optimistic! Im thinking that's too many drivers, too much power handling, and not enough grunt from my Marantz. Wharfedale states input power of 30-150W. If 30 is the minimuim, then 50W isn't offering much.... 50w is enough power to get decent levels out of a typical speaker like this. The main benefit with more power is cleaner sound when pushing the limits of the amp. Do you happen to have a receiver with pre outs? About a year ago I found they went on ebay for about $400, probably less now if you can do without HDMI. I ask because you could pick up a Behringer A500 for about $300 and get plenty of power. A nice bang for buck option. So the lack of power issue is one you can fix later. Generally I prefer a floorstander over a stand mount. They occupy the same space and either have more efficiency or extension and there is no stand to buy. Stands also look like they could topple a little too easily. And on this kind of budget, the cost of the stand can eat into the budget as well. BTW, based on their specs I think you will find they are 85 db 1w1m. Had they opted for a 2.5 way, it would be 88. A 6.5" midbass with an fs low enough to get them down to 30 Hz (-6) will be about 88 db, subtract 3db for bafflestep and you get 85. In a 2.5 way, both drivers do the bass, but only one does midrange. They haven't done that, but the bottom woofer crosses at 140 Hz, hence the only way to get 88 db sensitivity is by designing them to go right up against a wall. Don't be too put off by that, sensitivity ratings are almost always optimistic. You can use them to compare different models from Wharfedale, but probably not between manufacturers because they don't all use the same standard. They do seem like good value, but it's been a while since I've listened to commercial speakers in this price range. Usually they aren't set up to show what they can do.
Paul Spencer Posted February 9, 2011 Posted February 9, 2011 Impedance curve is here: http://www.stereophile.com/content/wharfedale-diamond-91-loudspeaker-measurements It appears quite well designed. Obviously they were thinking of surround use with receivers that don't like 4 ohm speakers, 6 ohms isn't a bad compromise.
Bus_Boy Posted February 9, 2011 Author Posted February 9, 2011 (edited) Well thanks for all the replies everyone. I went ahead and purchased the speakers today, and i should recieve them within a few days. Paul - Turns out the amp is actually 70 watts per channel, for some reason i thought it was only 50. It only states an impedance of 8 ohms. I didn't give any thought to matching the impedance levels of the speakers to the amplifier, i'm hoping the amplifier will be ok? Yes, the amplifier has pre-outs. Allthough would adding an external power amp, have a drastic impact over the way the current amps sounds? To me the Marantz sounds very warm, and is very easy to listen to. Infact i think it sounds better than my previous NAD amp, which was a much newer model. Also, yes i can do without HDMI. The only HDMI i use is for connection of the BRP to the TV, and it's only for visual, i use the optical output to the amp, and also the analouge outputs depending on the situation. That impedance curve says it's for the 9.1's, would the 9.5's be similiar? Edited February 9, 2011 by Bus_Boy
davewantsmoore Posted February 9, 2011 Posted February 9, 2011 Wi'm hoping the amplifier will be ok? It won't blow up. When the amp cannot properly drive a load impedance that low, it basically cannot control (stop) the cone movement as easily, and also exhibits uneven frequency response (rolled off bass is usually what you would notice most). See if you like it, you'll most likely be fine, especially at reasonable levels ... and you will have an EQ built into your AVR no doubt anyways.
Batty Posted February 9, 2011 Posted February 9, 2011 The impedance rating is only a nominal, as can be seen from freq v Z graphs Z varies with Freq. most common commercial amplifiers have enough headroom in their supplies to drive most common commercially available speakers, problems occur when Z drops down to say 0.5ohms. Basically your Marantz will drive the Wharfedales no problem. Please correct me if I'm wrong.
Bus_Boy Posted February 9, 2011 Author Posted February 9, 2011 Thanks Dave and Batty. I'm looking forward to receiving them. I haven't heard the 9.5, only the 9.1. If thy are anything like them then i'm sure i will be happy. I think it was a good deal considering the usual retail price they go for...
davewantsmoore Posted February 9, 2011 Posted February 9, 2011 Batty is correct (although I would have thought problems might show up before 0.5 ohm, which is very very low) ...... You'll be fine :-) ie. the effect of the low impedance load will likely be so very small that (especially on such speakers/amp and listening levels) you will not notice .
Paul Spencer Posted February 9, 2011 Posted February 9, 2011 BB, It's no big deal, 50w vs 70w. Either is fine. I used to run an old Akai with about that much power for quite some time and I was happy with the level. In terms of low impedance, I have a blog post about that: http://redspade-audio.blogspot.com/2011/02/can-6-ohm-amp-drive-4-ohm-speakers.html The short answer is, you should be ok as long as you don't push it. Make sure the receiver has enough ventilation. Yes, the amplifier has pre-outs. Allthough would adding an external power amp, have a drastic impact over the way the current amps sounds? Running preouts to a dedicated power amp will remove the sound of the amp and replace it with the new amp. I would not expect much difference, although I have not spend much time with Marantz amps so I don't know if they have done anything to get that warm sound people talk about. Perhaps they have some top end roll off or some kind of non-flat response. If that is so, this trait will go most likely. It's a little hard to say. When the amp cannot properly drive a load impedance that low, it basically cannot control (stop) the cone movement as easily, and also exhibits uneven frequency response (rolled off bass is usually what you would notice most). Sounds like you are talking about damping factor - that is not an issue here. The reason for specifying a limit for impedance is related to having to cut corners with the heatsink and power supply - some of the most expensive parts of an amp. When you design an amp, you have in mind the lowest impedance that it will see. If you set a higher impedance, that means the tranny will be smaller. That's the single most expensive part in an amp. The heatsink can also be smaller and you can save some cost with the output devices. They have to do all this to make some profit out of these very competitive receivers that sell based on features. BB, There is no great need to get another power amp just yet. You have the pre outs, so it's an option for an upgrade down the track. If you really do like the sound of your Marantz and find it has enough headroom, then stick with it. Although you never know what you might find - Marantz do also have power amps and you could pick one up second hand. Marantz receivers - always felt that they seemed to strike a nice balance between features and quality. I don't know about the impedance of the 9.5s but I would guess that they are probably not a difficult load, being designed with entry level AV receivers in mind.
pelennor Posted February 9, 2011 Posted February 9, 2011 Well thanks for all the replies everyone. I went ahead and purchased the speakers today, and i should recieve them within a few days.Paul - Turns out the amp is actually 70 watts per channel, for some reason i thought it was only 50. It only states an impedance of 8 ohms. I didn't give any thought to matching the impedance levels of the speakers to the amplifier, i'm hoping the amplifier will be ok? Yes, the amplifier has pre-outs. Allthough would adding an external power amp, have a drastic impact over the way the current amps sounds? To me the Marantz sounds very warm, and is very easy to listen to. Infact i think it sounds better than my previous NAD amp, which was a much newer model. Also, yes i can do without HDMI. The only HDMI i use is for connection of the BRP to the TV, and it's only for visual, i use the optical output to the amp, and also the analouge outputs depending on the situation. Based on my experience, yes, adding a power amp would make a big difference. I also have a Marantz SR-4200, and was running LSK F6s directly off the receiver. As soon as I added a power amp, the sound improved significantly, I guess better dynamics is the best way to put it. It also stopped some of the issues I was having with driving low impedance speakers (occasional receiver shutdowns, clipping at higher listening levels). I'm running Behringer EP1500s, but for what you're after a Behringer A500 would be just the ticket. Also note that since you're presumably running without a sub and thus running full range L+R, this puts more stress on the amp, since the lower frequencies are the hardest to amplify. Given this, I'd definitely opt for the power amp.
davewantsmoore Posted February 10, 2011 Posted February 10, 2011 Sounds like you are talking about damping factor - that is not an issue here. Is that becuase the output impedance of the amp is low enough (eg. < 0.1 ohm) to avoid more than 0.5db variation in FR (when also factoring in an average speaker cable between them) .... or is there some other effect ? Don't get me wrong, I understand it's a small issue.... and probably not noticable in a real room, etc.... but aside from SPL or power/heat issues (which have already been noted), I'm lead to believe non-flat FR as practically the only issue related to Z interactrions within the amp/cable/speaer system.
Batty Posted February 10, 2011 Posted February 10, 2011 Batty is correct (although I would have thought problems might show up before 0.5 ohm, which is very very low) ...... You'll be fine :-)ie. the effect of the low impedance load will likely be so very small that (especially on such speakers/amp and listening levels) you will not notice . my 0.5 ohms was just an example. I used it as a friend had a pair of IMF transmission line speakers that allegedly went that low. They did actually make my Cyrus 2 / PSX blow a fuse, but we were driving them quite hard with a bit of pink floyd - maybe it was just the transition that took out the fuse. Oi, keep your filthy hands off my desert.......... Boom!..... silence.
Paul Spencer Posted February 10, 2011 Posted February 10, 2011 Don't get me wrong, I understand it's a small issue Dave, It's not so much about it being a small issue, but rather there is no cause/effect relationship between damping factor and stability into various impedances. At least, not that I am aware of.
davewantsmoore Posted February 10, 2011 Posted February 10, 2011 A non-constant speaker Z will produce a non-flat FR .... dependant on the magnitude of the ratio of amp output Z and speaker Z (damping factor)..... The lower the speaker Z, the greater the FR deviation. In this instance, assuming a low amp out Z, and speaker cable of low resistance... the FR deviations is going to be potentially fractions of a dB (although I couldn't find the amp out Z quoted anywhere by marantz .... but a feedback SS amp is going to be very low) NB -- See my earlier remark about me making a whole lot of noise about nothing LINK: http://www.transcendentsound.com/Transcendent/Amplifier_Output_Impedance.html
Bus_Boy Posted February 10, 2011 Author Posted February 10, 2011 I'll wait and see how they sound, if i think they realy could do with the extra power, then i might pick up an A500. I've found them for $309 delivered https://www.storedj.com.au/products/BEH-A500?gclid=CM_J1uK8_aYCFQU3pAodPVihZQ
pete_mac Posted February 10, 2011 Posted February 10, 2011 Sounds like you are talking about damping factor - that is not an issue here. The reason for specifying a limit for impedance is related to having to cut corners with the heatsink and power supply - some of the most expensive parts of an amp. When you design an amp, you have in mind the lowest impedance that it will see. If you set a higher impedance, that means the tranny will be smaller. That's the single most expensive part in an amp. The heatsink can also be smaller and you can save some cost with the output devices. They have to do all this to make some profit out of these very competitive receivers that sell based on features. Indeed. Pretty good reading here on audiokarma on this general topic: http://www.audiokarma.org/forums/showthread.php?t=60386
Recommended Posts