DAC Comparison: Integrated Amplifiers vs PC Sound Cards vs Stand-Alone DAC's - Page 2

1 and 3 are OK; agreed that 2 is a waste.

An AVR qualifies as 1 or 3.

Trackfan, a pro audio active crossover is used to provide better isolation between the speaker system drivers and better control over them. Biamplified systems use an active crossover to control the drivers in the speaker enclosure, for instance. When you see large arrays of guitar amps and speakers, for instance, at a concert, you can bet that there are active crossovers in the system. They also allow for adjustments to be made to the crossover frequencies. Pro audio systems that use active crossovers do not have passive crossovers in them like virtually all home audio speakers. In order to use one in a home audio environment you would have to disconnect the passive crossover inside the speaker enclosures and connect the drivers directly to the active unit. In general, there is no practical place for active crossovers in home audio.

DSP is another thing entirely. It works in the digital domain. An active crossover works in the analog domain right at the speaker where any crossover works.

Finally, if what you want is a biamplified or triamplified system like those big concert speaker arrrays, then you need to use active crossovers. Biamplifying a speaker system with a passive crosssover is pretty silly since you are applying signal to both sides of the crossover with both amplifiers. Only an audiophile would do that. A pro audio engineer would know better.

Rubbish. Guitar and bass speaker systems are almost always simple multiples of the same drivers with nary a xover to be seen at all. Some BG speakers use a tweeter, but very, very few are active.
Rubbish. I have been running active systems at home for years, whether my own design or a modified commercial unit. All of the advantages of using active xovers are just as relevant in a domestic system as they are in PA.
Rubbish. A xover using a DSP is no less active than one that is all analogue. An active xover is simply one that separates frequency bands at line level rather than doing it as speaker level (post power amp). Using a DSP also allows the possibility of FIR filters, phase correction etc which are difficult or impossible to do in the analogue domain.

I agree with your evaluation of their web site.

I don't have any hands-on experience with the MiniDSP products, and don't want to become a shill for them. ;-)

Any recommendation would be specific to some detailed set of requirements.

You don't mention the efficiency of your speakers. If they fairly efficient (say >88dB) you might take a look at this amp:

http://www.nuforce.com/index.php?option=com_k2&view=item&id=306:dda-100&Itemid=370

It is claimed to keep the sound in the digital domain right to the speaker terminals. I've got one and it does sound exceptionally clean with no audible flaws I can hear. I also appreciate the minimalist styling and small size, but these factors don't affect sound quality.

Passive biamping, which is what you're describing is possible via the method you describe, but provides no practical or audible benefit over powering the speaker conventionally via a single amplifier channel.

Now that I can see where you are coming from, I will point out what others will no doubt shortly confirm, which is the electronics skills required to convert a well-designed speaker from using a passive crossover to one with equal or better performance using an active crossover are non-trivial.

While you can get fair performance with a simple off-the-shelf active crossover, most modern speaker's crossovers are tuned to compensate for the characteristics of the drivers. Doing this right at the minimum requires having an acoustical measurement setup, which in recent times has become something that is not impossible for the home constructor to obtain, but costs some bucks and takes time and effort to learn how to use,

I've been down this road with some success, but its nothing I'd recommend to someone with only rudimentary electronics skills except as an educational project. To get a speaker that sounds better than it did with a well-designed passive crossover takes more than rudimentary electronics skills going in, but if you do it right you will have more than rudimentary electronics skills coming out! ;-)

I did misread what you said. I also agree with Arny that implementing an active conversion in a commercial passive speaker is non trivial.

If that's all you think there is to designing good speakers, you have a lot to learn.

Cabinet building is relatively straightforward, especially if it's no more than a six sided box. The rest simply reinforces your ignorance of the subject matter.

Hi Trackfan, The complications are in the design. The size and shape of the box has a tremendous effect on the sound, and need to be "tuned" to the performance specifications of the drivers. Then, if you are building a ported speaker, the port length and cross-section need to be compatible with the drivers and box. Then there is internal cross-bracing to eliminate resonances, and optional fill for damping. It goes on and on . . .

It's a fascinating aspect of audio, though. There is free software available that allows you to design a "virtual" speaker, and then will show you the frequency response, SPL output and other qualities. Visit the "DIY Speakers and Subs" forum. Look at the flat-packs and the SEOS kits. You can build some truly great 'pre-designed' speakers for not a lot of money. Or you can learn to design your own. There is also a good discussion on passive-vs-active crossovers.

No kidding, there are some great kits to be had.
Both my 2 ch and my 5.2 HT speakers were
built by my hand, but designed by guys that have
been doing it for a long time with commercial
success. These out perform speakers that
cost many times the dollars I have invested.
In my mind the kits offered these days are the
best value for the $ in this hobby.