I came across this idea of having a 3.1 system after a visit to richersound and looking at Cambridge Audio CXA80 & CXA60 with floorstanding speakers and a REL subwoofer. I really did like the sound quality the Cambridge Audio CXA80 & CXA60 provided, and tried it with many speakers. Unfortunately this system with the floorspeakers just wouldn't fit on my desk, It wasn't quite loud enough, and was like £600 above my budget...
The 80W CXA80 plus a set of fairly sensitive(?) floorstanders didn't play loud enough!?! Jeez, just how loud are you expecting some system to go?
Although you’ll have some things working in your favour such as the proximity of the speakers, there are also some basic conflicts in your requirements.
We start with small speakers; it’s generally true to say that they won't be as sensitive as larger speakers. There is the odd exception e.g. JBL Control 1, but as a rule small speakers are less sensitive and so need more power from the amp to play as loud.
Going 3.1 versus 2.1 will help a little, but not so much that’s it’s a night-and-day difference.
To give you an idea, the impact of adding one extra speaker will give you about the same amount of sound increase as changing the main speaker sensitivity by 2dB. It’s generally agreed that 2dB is just about perceptible by an average listener. IOW, you might be able to tell it’s louder, but it won’t be by much.
In order to change the sound level significantly – enough to hear it as twice as loud – you’d need the intensity to change by 10dB. To achieve that would require going from two speakers to eighteen!
Setting aside the sound level for a second, the dB change with speaker sensitivity is important with respect to how much power is being drawn from the amp. A change in speaker sensitivity by just 2dB can change the power level required from the amp by 50%. That’s a big deal. Amplifier Watts cost a lot of money. Going from a 50W amp to a 100W amp of the same quality will cost way more than finding a speaker that’s 2dB more sensitive. Since it’s amplifier power that will govern how loud a system will play, then you should really spend some time getting to understand speaker sensitivities when they have this much of an effect on the final result.
Second, regardless of what the specs for AV receivers may claim, Hi-Fi amps have bigger balls than AV receivers when it comes to delivering raw power.
Pound-for-Pound spent, a stereo Hi-Fi amp will deliver more current than a similarly priced AV receiver. Part of the reason is that they’re not measured in the same way. Hi-Fi amp measurements are done in a very conservative way. It favours incredibly-low distortion, and so the quoted power is with the amp almost running on tickover. By contrast, a lot of AV receiver specs are quoted with just one or two channels running a specific test tone and at higher distortion levels. The result is higher “paper Watts” figure, but one that is the equivalent of the amp running flat out whereas the Hi-Fi amp still has a lot left in reserve.
By the sound of it though, you’re looking for something more brutal in sound delivery than you’d get with a Hi-Fi amp. This leads us then in to the more commercial realms where filling a space with sound takes precedence over extracting the last iota of detail from a recording.
Since you’re using your PC as the source, and it can control volume, bass/treble levels, speaker balance and so on then you don’t really need the pre-amp features of an integrated amp. You could dispense with the cost of that and go instead for a commercial power amp.
There are lots of home DJ power amps available, and plenty that seem to promise huge power outputs for relatively little money, but most can’t live up to their claims. Two brands that are trustworthy are Crown and Samson.
Of the two, Crown is superior, but Samson is thoroughly decent on a smaller budget. The Crown XLi1500 will give you 2x 330W in to 8 Ohms for around £500. More importantly, it has a switchable sensitivity setting that will give full gain with the sort of signal level you’ll get from domestic audio gear on unbalanced connections (0.77V) rather than requiring the full 1.4V from balanced audio signals from pro gear.
The Samson Servo 600 will deliver 2x 225W in to 8 Ohms for roughly £350. However, you only get maximum gain with an input signal level of 1.24V. Check your sound card specs to see what the maximum output voltage is rated at.
The price for all this power is that both amps use fans. The fans are temperature controlled, and so at low volumes the amp won’t be getting hot enough for the fans to kick in at high speed, but they will when you’ve got the volume cranked up. The sound level will obscure the fan noise, but it’s something to be aware of as these are not silent in the way a Hi-Fi stereo amp would be.
The next part of the equation then is speakers. The most sensitive are PA speakers, but they’re typically too large for desktop use and too ‘shouty’ for listening to at close distances. This is moving you away from sound quality to just sound level. The other catch is they’re often bass limited in a way that is surprising for their driver sizes. For example, the 6” mid/bass driver in the Hi-Fi brand Fyne F301 (8 Ohms, 89dB/W/m) allows the speaker to get down to around 60Hz before starting to roll off. By contrast, the 6.5” driver in an LD Systems Roadboy 65 (4 Ohms, 93dB/W/m) is rated to hit 80Hz. It doesn’t dig as deep.
PA speakers will play louder than their Hi-Fi counterparts because they’re built for power handling and filling a larger space.
Talking of power, a major caveat with passive speakers is they waste a fair chunk of power in the crossover. This is the circuit that any ordinary Hi-Fi or passive PA speaker has to separate the frequencies between the tweeter and the mid/woofer. It’s far more efficient to do this filtering before the signal is amplified. This brings us to active monitors.
When you see pictures of recording studios, the speakers closest to the mixing desk are called nearfield monitors. They’re designed for the sort of close distance use whereas ordinary Hi-Fi and PA speakers are designed to be used at 8ft+ from the listener. It’s also common to find that these have built-in amplification, and it’s the sort that filters the signal then has separate amplifiers for each driver. This means that no power is wasted in the crossover, and so the amplification wattages don’t need to be as high as with passive speakers.
Active studio monitors are available as singles, pairs and as 2.1 systems. The sub is the main signal connection point and then that feeds out to the left and right speakers.
Studio monitors combine the precision of Hi-Fi speakers with the sort of efficient design that means you’re getting the most sound from your budget.
As a starting point to get your head around the way these things work, have a look at this JBL kit.
JBL 308P MKII Studio Monitors with 310S Subwoofer at Gear4music Once you're comfortable with the idea of a studio monitor kit you can speak to one of the retailers about which monitors play the loudest and mix-n-matching different/larger/more powerful subs.
If you prefer the idea of a power amp, stereo speakers and humungous sub then a pair of JBL Control 1 (c. £100) + a 200W @ 8 Ohm power amp (c. £300) + and SVS PB1000 sub (c. £640) will give you loud on the desktop and bass to rattle your teeth.
