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Are KEF-IQ30 adequate for my bedroom? And how can I amp them?, Need help since it's my first sound system.
eduardokbb
post May 21 2012, 20:47
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Hello Hydrogenaudio community!

This is my first topic and I hope I didn't placed it in the wrong section. If I did, please move it to the right section and I'm really sorry for that inconvenience, but I had not find a better place. Oh, first of all, I'm not very good with english, so you'll probably find some minor [or not so minor] errors, even though you'll be able to understand what I'm trying to ask!

Well, I live in Brazil and it's a 3 world country, electronics are extremely expensive here and I'm not one of the riches that can afford the most expensive components. This year I decided that I would save some money to buy a decent sound system for my bedroom. I'm still saving the money, but I don't really know if the speakers and sound card I decided to buy are the right ones to go.

My idea is to buy a pair of KEF IQ-30 for stereo speakers and for the sound card an Asus Xonar Essence STX. I'm going with the STX instead ST because it has an integrated headphone amplifier, it's a mini pci-e card (the ST is just mini pci and its getting a little obsolete), and it's a little cheaper. The headphone, after a lot of research is an ATH-M50W.

Below is a picture of my desktable

The desk has 130cm x 60cm. The KEF IQ-30 would replace my low quality Philips speakers. The Philips speakers are connected to my Philips micro system that is said to amplify 26W rms 8 Ohms, but I really doubt they can perform that.

The question is, will this KEF speakers be good there? The bedroom itself measures something like 10m. How may I amplify the new IQ-30 speakers? I mean, my Philips speakers are connected to their Philips micro system and the system is connected to my computer's motherboard. The thing is that the IQ-30 speakers will demand some power that my Philips micro system will not be able to do. I need a cheap provisory solution to that. Something to connect the speakers to the Asus Essence Sonar STX and to amp them. It's provisory because, in the future, I'll buy a Denon 3312, but I don't have money to buy everything together. I would appreciate if someone could help me with that, I just don't know what to do. I need to amp the IQ-30 for a 10m room and to connect the speakers to the sound card.

Oh, and I'll take this topic to ask you another thing! Since I'm upgrading to an off-board sound card and getting a really nice sound system (at least the best I can afford), I'm thinking about having a good recording microphone. If you can see my desktable in the picture above, there's a webcam placed near the monitor. That is my recording device and it really sucks, it's even worse than me Philips speakers, haha! My idea is to buy a Shure SM58 and directly connect it to the Asus Sonar Essence STX mic input by using a XLR to 6.3mm jack cable. I'll handcraft by myself a support base for the microphone and screw it in my desk. Will this work? I mean, connecting directly the mic to the soundcard.. and if it does work, will it sound good? Oh, and about the handcrafted support base... well, my desk is a cut door with table legs screwed at it, so if the support doesn't work well and my table get damaged, it will be cheap to get another table, haha!

I would really appreciate your comments about my ideas because I'm really lost in this audio world. Thanks for your attention and sorry for poor english, but I gave my best! Thanks!

This post has been edited by eduardokbb: May 21 2012, 21:18
Reason for edit: testing . . .
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mzil
post May 22 2012, 00:01
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I don't think you should buy anything as an interim solution before you get the Denon 3312. I think you should instead connect the IQ30s to the micro system and see how that goes, first.

KEF suggests amplifiers in the range of 15-100 watts for those speakers, so if your Philips really does put out 26 wpc, 8 ohms, low distortion, both channels driven, full bandwidth, that falls within their suggested range. I think you might be surprised at how good it sounds, and of course the price of my suggestion is free, yet easily abandoned if you feel the results are unsatisfactory.

Listening at very loud levels, at a great distance, or attempting to fill a much larger room might pose a problem though.

Of course my suggestion would most likely be immediately pooh-poohed and dismissed by a dealer, who just so happens to sell other things you might use, but obviously such people have ulterior motives.

My ex-girlfriend drove speakers with even lower efficiency than yours (your KEF are 89 dB/1w(2.83V)/1m) using a Nakamichi micro system which could only put out 13 wpc, and I think that was only at 1 kHz, with perhaps 5-10% THD, maybe not full bandwidth (at 1kHz, only), and it filled her average sized city apartment, at modest levels, just fine.

P.S. Your Philips system probably has ventilation slits along the top edge, perhaps on the back, and you compromise the chimney like ventilation aspect by placing it on its side, as I see in the picture. This may not be a problem now, but if you attempt to drive a more difficult load, or at louder levels for an extended period, it could be a heat build up issue. Just a heads up.

This post has been edited by mzil: May 22 2012, 00:35
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eduardokbb
post May 22 2012, 02:06
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http://download.p4c.philips.com/files/m/mc..._21_pss_eng.pdf [it's the leaflet that says my micro system can perform 20w music power, haha]

Well, like I said before, I have had my doubts that this micro system could perform the 26w 8ohms, than I downloaded the leaflet [what I've always called datasheet] of my Philips micro system, and, in contradiction with what is printed behind the micro system itself, the leaflet says my system can just perform 10w RMS per channel or 20w music power, that I swear my life I don't know what the hell this music power has to say about anything. To be honest, I don't really need a loud system, my bedroom measures 10m and my mother's bedroom is just behind the green wall you can see in the picture... in other words, even with a 100w RMS power amplifier I wouldn't be able to use all of that. Well, you made me realize that I'll only know if I'll need something more after buying my KEF IQ-30 and trying to run them on this system to see how it goes. You may be right, maybe I don't need to waste money with amplifiers right now. It makes me wonder if I really would need the Denon 3312, I mean, I was thinking in this receiver because it can amp 125watts RMS per channel, and I probably wouldn't ever run my system with 100watts RMS anyway. But amplifying doesn't just make the sound louder, right? It improves a lot of things, I guess.. I don't know, haha! I'll search about it.

Oh and about the ventilation.. the ventilation slits are located behind and below the system. Placing him on its side blocks no slits. Was that what you were afriad I were doing? If so, that's alright!

And about the Shure's microphone as a recording device, don't you have any sugestions or opinion to help me? In fact, I don't even know if what I'm thinking is possible to be done, haha! Thanks for your attention and sugestions!

This post has been edited by db1989: May 22 2012, 09:30
Reason for edit: deleting pointless full quote of above post
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mzil
post May 22 2012, 04:47
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Can't help you with the mic. Sorry.

This post has been edited by db1989: May 22 2012, 09:31
Reason for edit: as above. That was absurdly huge.
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Arnold B. Kruege...
post May 24 2012, 12:23
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QUOTE (eduardokbb @ May 21 2012, 15:47) *
My idea is to buy a pair of KEF IQ-30 for stereo speakers and for the sound card an Asus Xonar Essence STX. I'm going with the STX instead ST because it has an integrated headphone amplifier, it's a mini pci-e card (the ST is just mini pci and its getting a little obsolete), and it's a little cheaper. The headphone, after a lot of research is an ATH-M50W.

Below is a picture of my desktable

The desk has 130cm x 60cm. The KEF IQ-30 would replace my low quality Philips speakers. The Philips speakers are connected to my Philips micro system that is said to amplify 26W rms 8 Ohms, but I really doubt they can perform that.

The question is, will this KEF speakers be good there?


You've probably got problems with where you have the speakers. Usually a desktop like that is not the best. The ones you have would probably sound better if you raise them off of the desk a few inches to a foot or more and point them at your ears. The benefits of better speakers can be diluted by putting them in a bad location. Usually, the top of a table pointed at your belly is not good.

QUOTE
The bedroom itself measures something like 10m. How may I amplify the new IQ-30 speakers? I mean, my Philips speakers are connected to their Philips micro system and the system is connected to my computer's motherboard. The thing is that the IQ-30 speakers will demand some power that my Philips micro system will not be able to do.


Speakers don't demand power. That is the role of the nut that hold the volume control. ;-)

Your actual power needs are highly dependent on how loud you want the music to play. There is some chance that the IQ30s are actually more efficient than your existing speakers and so for an equal loudness, they may actually need less power. Power for driving speakers can be very counter-intuitive. You can look at a speaker that is 6' tall and 10' wide and think that you need a power amp connected directly to the power station to run it. In fact due to its size it may be highly efficient and run well or even blow you away with a watt or two.


(1) Experiment with relocating your existing speakers away from where they are now to get better sound. Much of what you learn about that will help you with your next speakers.

(2) Your existing receiver may seem puny, but in a room the size of yours it might be more than enough to get you into trouble with your neighbors.

(3) Understand that larger speakers may be more efficient and play louder cleaner with the same ampliifer or receiver.

(4) If the sound card in your computer is modern and, you may be disappointed when you upgrade it because new one won't sound that much better.
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eduardokbb
post Jun 8 2012, 18:47
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I appreciate your help Arnold. I did some research about speaker efficiency (or sensibility) and I think this system really is more than enough, doesn't matter what speakers I intend to use, because my room has a very limited space. I'll see how can I put the speakers in a higher place to see how it goes.
About the soundcard, my actual soundcard is an integrated one. By doing some research and asking my mother's boyfriend (an electricist) I realized that connecting a Shure SM58 microphone directly to the soundcard (and it doesn't matter if it's an integrated one or an Asus Xonar Essence STX) wouldn't sound good because the microphone needs to be amplified. Computer's microphone channel doesn't have enough power to amplify a standard microphone. It can just amplify headsets or other "computer microphones" because they're designed to operate with less power. A Shure SM58 or any other XLR professional microphone will demand more power, in other words, the sound will be really low... to make it work properly, I would need a pre-amplifier between the microphone and the soundcard. I did some research about what can be used and I found a really nice pre-amplifier called "M-Audio Buddy". This M-Audio is just a pre-amplifier, meaning that the hard work will be done for your soundcard. There are other M-Audio products that do all the job.
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eduardokbb
post Jun 8 2012, 18:47
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Double Post, sorry.

This post has been edited by eduardokbb: Jun 8 2012, 18:47
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stephan_g
post Jun 9 2012, 17:27
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First of all, why do you want an SM58 anyway? This is a standard vocal mic. Being a dynamic mic, they are tough as nails and as such a popular choice for live performances. Usually being mere centimeters away from the performer's lips, their moderate sensitivity (as typical for a dynamic mic) does not matter too much - in fact, at very high levels their output can be in the volts! Frequency response is EQ'd accordingly, in order to compensate for proximity effect. If you want to record vocals, fine. It's not good for podcasting, and not at all good for any kind of ambient recordings.

The SM58, being entirely passive, does not require phantom power. However, the wiring must match the input. A microphone wired up with balanced cable (i.e. twisted pair) needs a balanced input, otherwise it may catch all kinds of stray radiation, which is highly annoying given the low basic sensitivity. The only exception would be one that uses a shielded twisted-pair cable and XLR plug, and the shield is properly connected by the adapters used. (Anything with a 1/4" TS plug is likely to be problematic.)

PC soundcards usually have unbalanced inputs. Any mic used there would have to use some sort of shielded (coaxial) cable. There are two different pinouts commonly in use:
TS (mono) plug: tip = signal plus +1..5 V supply for electret capsule (which has an integrated JFET), sleeve = ground (typical pinout for onboard audio and such)
TRS (stereo) plug: tip = signal, ring = electret supply, sleeve = ground (Creative pinout)

The M-Audio Buddy with its balanced inputs and phantom power would enable you to use just about any pro mic, up to large diaphragm condenser mics. Seems a little oversized for just a SM58, but provides plenty of room to grow.

Incidentally, the only major difference between the Xonar ST and STX is the interface (PCI vs. PCIe). The STX also requires an extra power connection - not because it would be a power hog, but because PCIe does not provide +5V. The accompanying extra ground connection may be why it turns in less clean measurements than its PCI colleague. Otherwise, they are identical, headphone amplifier section included.

Some "proper" HiFi speakers like the iQ30 should make a fairly large difference. You may not get their full performance with the chipamp inside the Philips micro, but it should be quite a step nonetheless.

Finally, I can only echo the following:
QUOTE (Arnold B. Krueger)
You've probably got problems with where you have the speakers. Usually a desktop like that is not the best. The ones you have would probably sound better if you raise them off of the desk a few inches to a foot or more and point them at your ears. The benefits of better speakers can be diluted by putting them in a bad location. Usually, the top of a table pointed at your belly is not good.

Here it looks about like this:

The stands were made using some pieces of beech and feet obtained from a hardware store. Having handy family members has its pros...

This post has been edited by stephan_g: Jun 9 2012, 17:31
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Gecko
post Jun 9 2012, 22:20
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Two more things:

1. Your speakers seem to be very close to the wall. Make sure you are not blocking any rear bass-reflex ports. (Although the picture suggests the bass-reflex ports are actually on the front.)

2. The Denon 3312 is an A/V receiver. Is that really what you need, or would a stereo amp be enough?
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