I am really pleased with the number of replies to this post. Thanks to all who took the time to answer! I didn't realize how many people were into diy electronics. I'm an old aeronautical engineer / woodworker without much experience in electronics. I looked at all the websites mentioned and quite frankly couldn't absorb much of it. I'm much more comfortable buying something already in a box that has a user's manual to tell me how to turn it on. However, I did build the passive crossover, that Lou Corragio designed for me, for my first DIY speaker project (see attachment).
I plan to build one of Troels Graveson's designs, I'm debating which. He did have a statement on his web site that I didn't understand and that was he didn't recommend an active x-over unless it was digital. Maybe one day I'll ask him about that.
Thanks again,
JohnZ
I plan to build one of Troels Graveson's designs, I'm debating which. He did have a statement on his web site that I didn't understand and that was he didn't recommend an active x-over unless it was digital. Maybe one day I'll ask him about that.
Thanks again,
JohnZ
One more supplier...http://groundsound.com/
Seems like some of you claim there are "perfect solutions" but I doubt this. Digging deeper into both the problem and the suggested solutions may disclose some compromises that have to be made. Implementations of digital crossovers normally means that one have to convert the analog signal into a digital one, process it and then convert it back to analog and although this in theory can be made without much losses or degradations to it, in reality some negative enough errors may show up. Keeping the signal in the digital realm to the end, like the advanced and expensive systems i.e. Goldmund produces may help but the system gets complex and expensive.
Seems like some of you claim there are "perfect solutions" but I doubt this. Digging deeper into both the problem and the suggested solutions may disclose some compromises that have to be made. Implementations of digital crossovers normally means that one have to convert the analog signal into a digital one, process it and then convert it back to analog and although this in theory can be made without much losses or degradations to it, in reality some negative enough errors may show up. Keeping the signal in the digital realm to the end, like the advanced and expensive systems i.e. Goldmund produces may help but the system gets complex and expensive.
I built a 2-way active crossover using Rod's P09 board.
The decision to go active was because I did not have the necessary know-how/tools to make my own passive crossover.
I basically looked at the published response graphs of the drivers I had (Scanspeak 8545/9700), and chose a crossover point.
I'm very very happy with the result.
The decision to go active was because I did not have the necessary know-how/tools to make my own passive crossover.
I basically looked at the published response graphs of the drivers I had (Scanspeak 8545/9700), and chose a crossover point.
I'm very very happy with the result.
The dbx drive rack PA is a very nice all in one solution - 2in 6out crossover and 32 band digital EQ + a bunch of PEQ's and limiters etc. Street price of around $400. If you get an RTA mic you can just plug it into the dbx, press a button and it'll pink the room and automatically adjust the 32 band eq to give you a good starting point for a flat response at the listening position. It's very intuitive to use...
The catch is that you have to either pad down the output from the dbx, or just use it with pro amps. Why? Consumer level gear uses a different signal level than pro gear. You can't always mix the two. The dbx will accept consumer level input, but will only output pro level signal.
Also being digital, it's very useful if your amps have gain controls so you can maximize your gain structure - this is very important if you want to avoid hiss and get the most resolution out of you a/d & d/a converters.
Also plugging the drive rack into a UPS is a must. If you were to have a power outage the dbx will send a huge pop through your speaker that could blow a tweeter.
If set up correctly you shouldn't have any issue with hiss. I'm using mine with 115db/w/m horns and I have to have my ear 4" from the tweeter before I can hear any hiss. Hiss is only a problem if you have poor gain structure.
The behringer is also a nice unit I bet. But you have to by both the DCX and DEQ to accomplish what the drive rack can do. However the behringer can also do a few things that the driverack can't.
Good luck with your project!
The catch is that you have to either pad down the output from the dbx, or just use it with pro amps. Why? Consumer level gear uses a different signal level than pro gear. You can't always mix the two. The dbx will accept consumer level input, but will only output pro level signal.
Also being digital, it's very useful if your amps have gain controls so you can maximize your gain structure - this is very important if you want to avoid hiss and get the most resolution out of you a/d & d/a converters.
Also plugging the drive rack into a UPS is a must. If you were to have a power outage the dbx will send a huge pop through your speaker that could blow a tweeter.
If set up correctly you shouldn't have any issue with hiss. I'm using mine with 115db/w/m horns and I have to have my ear 4" from the tweeter before I can hear any hiss. Hiss is only a problem if you have poor gain structure.
The behringer is also a nice unit I bet. But you have to by both the DCX and DEQ to accomplish what the drive rack can do. However the behringer can also do a few things that the driverack can't.
Good luck with your project!
phase_accurate said:
Yeh, I know....but some guys do not admit they are making priorities. Why? Are they living in another universe? Or do they believe in ads?
With much resources like financial one´s you may be able to make some less degrading compromises though, if you have the skills. But sometimes competence "in making" beats great resources and I have heard some very expensive systems sounding mediocre. Last time in february in Stockholm at the annual Hi-fi show, one of the most expensive system didn´t manage to sound realistic to my ears. But some may have been impressed by the sheer price of the system.
It would be an advantage I think if the Hi-fi press could speak out about this phenomena. I call it incompetence to deliver bad sound given huge resources and the mags "unable" to write about it!
And I do believe that some DIY people clearly have more skills than some "professionals". Some but not all professionals of course...Maybe doing it passively is the easy way out,buy the componenents for an established passive design then you can see if you can improve it actively with a fallback if you cant.Something like an Ashly XR2001 is an easy starting point, if you go down the Behringer route volume control gets a bit more complicated.
col said:
I though that the OP was looking for an off the shelf solution?
At any rate, I'm sure there are far better x-overs than the dbx & behringer, but they pack a lot of bang for the buck. For me the ability to eq for the room is major.
I'm running the dbx through some pretty nice drivers & horns (Altec 288-8K's, GPA 515G's and Gauss 1502's) and the dbx is holding it's own - the sound is really something to behold - a huge leap from the B&W Matrix 801's sII I was using before.
While I'm sure it would be even better with a better crossover, I think in the context of the overall system, electronics pale in comparison to the contribution from the speakers and room.
Edit: this might be of interest - someone who is going to compare the dbx, dcx and modded dcx
http://www.avsforum.com/avs-vb/showpost.php?p=16544725&postcount=101
There are plenty of options for EQ'ing without having to tie it to bad opamps in a "music centre" crossover.
I use a DEQ2496 which has a great DSP with RTA, as long as I only use it with the digital I/O and avoid the analogue in/outs, it provides all the EQ'ing I need.
I agree that the contribution that the room and speakers make is by far the determining factor in the quality of the sound though.
col.
I use a DEQ2496 which has a great DSP with RTA, as long as I only use it with the digital I/O and avoid the analogue in/outs, it provides all the EQ'ing I need.
I agree that the contribution that the room and speakers make is by far the determining factor in the quality of the sound though.
col.
I have to say that I use the cheapest Behringer CX2310 and it is a cost effective solution to XOs in the bottom octaves.
In answer to Cols comment on ground-loops ; I have never previously had a problem, but in my new house I do have a consistent low level hum which so far I've been unable to get rid of.
Col if you have any comments on a fix I would appreciate your input.
Regards
Ted
In answer to Cols comment on ground-loops ; I have never previously had a problem, but in my new house I do have a consistent low level hum which so far I've been unable to get rid of.
Col if you have any comments on a fix I would appreciate your input.
Regards
Ted
Ted, read this thread (throughly):
http://www.diyaudio.com/forums/showthread.php?s=&threadid=115698&perpage=25&highlight=&pagenumber=1
Iv'e applied the ESP ground loop breaker to all my amps and the crossover, plus Iv'e balanced all my interconnects.
col.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=115698&perpage=25&highlight=&pagenumber=1
Iv'e applied the ESP ground loop breaker to all my amps and the crossover, plus Iv'e balanced all my interconnects.
col.
A couple more interesting things about going active, at least in my system. Probably as a consequence of limiting the bandwidth of each section, the sensitivity of the system to speaker cables, op-amps power amps and other components is less. Whatever difference there might be between speaker cables tends to disappear. You'll also get tremendous SPL from modestly powered amps, all working well within their capabilities, rather than one big amp that's flirtin' with disaster.
I'm taking "activation" in stages before jumping into a full from-the-ground-up project (as I wanted to experiment with one of the drivers before putting it into another setting).
So my first active setup was modifying an existing passive speaker system (a small pair of Dynastatics) which I had already listened to at some length in their standard configuration. My reason for trying active was that, as a passive system, my NAD amplifier wasn't coping well with the load presented by the electrostatic panels and I was interested to see if controlling the individual drive units with their own amplifier would make *that* much difference.
I used a second-hand Behringer CX-3400 crossover, split my NAD 3150's pre and power amps (pair of external links) and added a pair of mosfet amp modules I had lying around from another experiment.
Knowing the approximate x-over frequency of the Dynastatics really helped as I only needed to match volume levels generated by the slightly differing power outputs from the power amps (NAD's driving the electrostatic panels are "50W" and BK modules driving the bass units are "200W" - inverted commas because I think the NAD power supply probably makes their spec a bit conservative).
The flexibility of having easliy variable crossover frequencies and output levels from the CX-3400 has certainly been useful in experimenting and tweeking the setup. I haven't needed the limiter or time delay facilities as the driver alignment is unchanged in my speakers.
As a starting point, this flexibility certainly helps over some of the kits Google found for me, where you have to swap components or modules to effect the change. I'm undecided yet as to whether to swap to different active modules built into the speakers along with amp modules for the next phase.
I'm really pleased with the resulting improvement in overall sound, which is better controlled, much more dynamic especially on percussive material and the NAD amps don't show the signs of distress that they did before, at least not until higher sound levels.
Hope this is of some use. I'm ready for the next step in the project now
cheers
Nick
So my first active setup was modifying an existing passive speaker system (a small pair of Dynastatics) which I had already listened to at some length in their standard configuration. My reason for trying active was that, as a passive system, my NAD amplifier wasn't coping well with the load presented by the electrostatic panels and I was interested to see if controlling the individual drive units with their own amplifier would make *that* much difference.
I used a second-hand Behringer CX-3400 crossover, split my NAD 3150's pre and power amps (pair of external links) and added a pair of mosfet amp modules I had lying around from another experiment.
Knowing the approximate x-over frequency of the Dynastatics really helped as I only needed to match volume levels generated by the slightly differing power outputs from the power amps (NAD's driving the electrostatic panels are "50W" and BK modules driving the bass units are "200W" - inverted commas because I think the NAD power supply probably makes their spec a bit conservative).
The flexibility of having easliy variable crossover frequencies and output levels from the CX-3400 has certainly been useful in experimenting and tweeking the setup. I haven't needed the limiter or time delay facilities as the driver alignment is unchanged in my speakers.
As a starting point, this flexibility certainly helps over some of the kits Google found for me, where you have to swap components or modules to effect the change. I'm undecided yet as to whether to swap to different active modules built into the speakers along with amp modules for the next phase.
I'm really pleased with the resulting improvement in overall sound, which is better controlled, much more dynamic especially on percussive material and the NAD amps don't show the signs of distress that they did before, at least not until higher sound levels.
Hope this is of some use. I'm ready for the next step in the project now
cheers
Nick
I am currently building a tri amped system. I am using state variable filters so that the crossovers points are exactly phase aligned. As for driver acoustic slopes I get round this by crossing in the drivers passband. Also using a bass boost circuit to get an extra octave out of my subs. I get round the ground hum issues by building all 3 amps and crossovers and digital volume controll in the same case and only grounding each transformers center tap and not running signal grounds between circuits, therby no loops while everything is still ground referanced. Not optimal I would like to go fully balanced but my source is unbalanced and I can't afford the extra expense.
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