Biamp crossover question

[boputnam]

...I figured that I could go total active 4 way

If you do choose to get so complicated, Steve (and wanna spend all the dough needed on extra amps... ) you might consider trialing something like the BSS FDS-334T/336T MINIDRIVE or KT DN9848 units. Their output channels have multi-point parametrics for fine tailored control, as well as delays for time-alingment, shelving filters, etc.

If you have, or can borrow the needed acoustic measurement gear, you might have a real interesting time seeing what you can hear...

[Steve Gonzales]

Thanks Bo, I've got a tri-amped system already so it's not that much more complicated. I've got the midbass amp already too. What I need is the crossover and enclosure. I look at my system as an evolution in progress. BTW, that auditorium/concert hall is B-E-A-utiful!!!

[edgewound]

Wasn't so much opinion, as reality. I was classically trained on bass trombone, and my sister is an opera singer, so I've spent ample time in many halls, nationwide as many of us have.

Support local music!

Bravo to supporting local music.

Bo, I have utmost respect for your opinions and your technical knowledge of live sound and music...recorded or otherwise....and I'm not arguing your points.

My point is...if all that technical science on acoustic architecture and electronic tuning were mandatory in getting a satisfying musical listening experience at home....no one would ever do it. Thank God all those symphonic halls exist, and the geniouses that design and engineer them.

Most listeners are not going to... nor be able to afford...to build a money is no object listening room. I think great sound is do-able using minimalist approaches to system design...that's all.

And....most local music venues...bars, restaurants, nightclubs, city concerts in the park, are hardly designed from the ground up for great acoustics. That's not my opinion...it's my experience. Been there...still doing it

[Mr. Widget]

If you have, or can borrow the needed acoustic measurement gear, you might have a real interesting time seeing what you can hear...

I have to say that without access to real measurement equipment you will be playing around in the dark. It is true that the ultimate judge for how successful you are will be you and your ears, but having set up quite a number of multi-amped systems, I know you will always be fiddling around with it because this or that recording doesn't sound quite right.

Even with the measurement equipment and the knowledge of how to use it properly, you will still need to tweak it a bit, but it will make your ultimate results so much more satisfying when your system is set up properly. I suppose this is why some think that a properly set up passive crossover sounds better than an active one.


Widget

[edgewound]

I suppose this is why some think that a properly set up passive crossover sounds better than an active one.

Widget

Very valid point. Constantly tweaking the crossover or EQ doesn't strike me as being a rewarding listening experience. Some like to have more stuff to fiddle with...and there's some fun in that too.

[Ian Mackenzie]

Well, I've been running a tri-amped system for some time now, so I'm fairly familiar with the basics. I'm not doing this for kicks, I've got some 136a's that have been completely, professionally rebuilt, some 2123H's, 2397/2441's and about 4 pairs of 076's, so I'm serious about building a four way. I just wanted to get some advice about the crossover choices. I figured that I could go total active 4 way, tweeked bi-ampable 4way passive or custom 4 way passive. I admit that my questions are fuzzy but believe it or not, the answers would allow me to connect some dots about my final choice. I also might choose the 2235H for the bottom and I can get some 2122H's also, so I really need to figure this all out, looks like I'm leaning towards full active. Thank you, gentlemen, great info.

The problem is you need to know how to go about it and that is why I refered to Elliotts Sound Pages and hence the hints from other posters in this thread. Quad amping isn't necessarily the answer nor the most practical way of going about it.

What you could do is buy a SH Driverack for experiementation and get it to give you a flat response. Then somehow measure the voltage drives to the components and then arrange a high quality work around. A better way is just a bunch of DEQX's .

[hapy._.face]

Having a quad amp system could be heaven or hell- depending on the set up. If you give an average guy a few dozen knobs to turn- he will probably tweak to his satisfaction- even if that means the recording integrity gets tweaked, too. I (personally) would want to know what the room was doing (via software) before I introduced such a complex system.

Widget's notion of letting your ears be the ultimate judge (while correct) seems only valid if your ears have been trained to know proper sound. Most people don't know proper sound unless they have been in the industry, or associated with a proper system.

We all know that amps perform differently- depending on the volume. Now multiply that times four. Factor in the extra protection that a quad amp set up usually requires, the symbiotic relationship your preamp/amp takes on- and you might be so far removed form the original signal (sounding "good" prehaps) that nothing really matters.

I agree with the whole 'less can be more'. I prefer to introduce the least. Keep it simple. An excellent passive- made to the exacting specs of your drivers- is (IMO) the ultimate way to go. I can see biamping - but I would stay away from tri/quad with full active unless I really knew what I was doing.

Now I have a question - don't most (off the shelf) active Xovers only address slope and freq? How do they compensate for Fs? How can they perform as good as a custom passive if they are (indeed) this vague/general?

[edgewound]

Now I have a question - don't most (off the shelf) active Xovers only address slope and freq? How do they compensate for Fs? How can they perform as good as a custom passive if they are (indeed) this vague/general?

Choose your crossover points well within the flatest, most well behaved response areas of each driver....then apply eq cut to the offending areas should there be any.

[Robh3606]

Now I have a question - don't most (off the shelf) active Xovers only address slope and freq? How do they compensate for Fs? How can they perform as good as a custom passive if they are (indeed) this vague/general?

Your typical 24dB L-R analog crossover has two basic user controllable parameters. Attenuation and what the crossover frequency is. That's it. You are adjusting the over all level, the level in each passband and in a 2 way where the crossover point is between the drivers. Not sure what you mean about Fs?? If you mean the woofer well the box handles that. The rest of the drivers are wide open you can drop the crossover bellow Fs on a compression drivers rather easily.

Having a quad amp system could be heaven or hell- depending on the set up.

It's hell plain and simple. The more complexity you add the harder it is to make it sound right. Getting it balanced right even with an RTA, so it really sounds "right" is an exercise in real patience. I may take you a month before you finally have it dialed in where you want it. Chances are excellent it won't be the same curve you worked hours on with careful adjustment on levels and set-up when you started. When your all done you have to record all the settings and take a curve snap shot so you can get back there if anything gets changed. It sounds so simple just set-up the microphone watch the curve on the RTA when it looks good your done. Sure you are!

The one thing I have learned doing active is just how hard it is to design a really good crossover. There is a reason the passives have asymmetrical slopes and non textbook implementations. Some of these driver integrate best that way. That's why you always build the passive if for example you are going for a clone. You may never be satisfied with what you get using the fixed filters in these inexpensive crossovers. More importantly you may never get to hear the drivers integrated properly like a passive network can do.

Rob

[Mr. Widget]

What he said...


Widget

[Ducatista47]

Well, I've been running a tri-amped system for some time now, so I'm fairly familiar with the basics. I'm not doing this for kicks, I've got some 136a's that have been completely, professionally rebuilt, some 2123H's, 2397/2441's and about 4 pairs of 076's, so I'm serious about building a four way. I just wanted to get some advice about the crossover choices. I figured that I could go total active 4 way, tweeked bi-ampable 4way passive or custom 4 way passive. I admit that my questions are fuzzy but believe it or not, the answers would allow me to connect some dots about my final choice. I also might choose the 2235H for the bottom and I can get some 2122H's also, so I really need to figure this all out, looks like I'm leaning towards full active. Thank you, gentlemen, great info.

Steve, 2245H's are plentiful, new to basket cases. If it is experimenting you are after, nevermind. But you have most of a 4345 pair in hand. Go 18" instead of 15". Build those and biamp them, and you will create something more rewarding to listen to than any amount of experimentation will likely ever produce. Believe me, I know how rewarding listening to a biamped, four-way 2245H-based system done right is. Widget and Subwoof feel a 2" compression driver is preferable for high spl's, and crossover possibilities are quite open. Who knows, you might bring the 4345 sound to a new level and we will all beat a path to your door.

Personally, I wish someone would update the design with current (improved) JBL drivers that are here and now. Problem is, it would take Greg Timbers to design the crossovers and baffle. I hear he is future-looking and otherwise engaged.

But bottom line, I think you will like your project much better in the end if you use the 2245 and 2122 drivers. What a potent combo they are.

Clark in Peoria

[Mr. Widget]

Widget and Subwoof feel a 2" compression driver is preferable for high spl's...

I think 2" drivers are preferable at whispering low SPLs too... I am not really into really loud these days... getting older you know.


Widget

[hapy._.face]

I think 2" drivers are preferable at whispering low SPLs too... I am not really into really loud these days... getting older you know.


Widget

This guy isn't into 'loud' either

[4313B]

Personally, I wish someone would update the design with current (improved) JBL drivers that are here and now.

Ok! That's easy! Shazam!

[norealtalent]

You mind sending those over to my house for a while?