Possible 1st DIY, 4 way active TMWSS tower

**ThomasW** · 03 March 2007, 10:56 Saturday

For the best sound quality, home audio systems unlike car audio systems requires things like baffle step compensation, zobels (impedance compensation) and custom crossovers designed specifically for the baffle the drivers are mounted. These things aren't obtainable from a generic active crossovers.

In home audio 8" drivers aren't really "subwoofers", since they simply can't move enough air to adequately reproduce the low bass in DVD soundtracks.

The technique for designing a home system is a follows.

Buy the test equipment and software needed for making accurate measurements of the frequency response and impedance of the drivers mounted in your proposed baffle.

Import that data into a crossover design program. Based on your measured data create a crossover that optimizes performance.

Build a crossover from the design you created, then fine tune that design using more measurements and listening tests.

**cjd** · 03 March 2007, 12:41 Saturday

If you want to have some ability to handle baffle step and all the rest in a "pro" crossover you're looking at the Behringer DCX2496 instead of the CX.

In my experience it's not going to sound as good as a good passive crossover, but neither are the components you're choosing necessarily going to care about the subtle differences.

8" is not a sub. Unless your room is about the size of a car cabin.

C

**ttan98** · 04 March 2007, 20:35 Sunday

cjd

can you be more precise on how to adjust on the DCX 2496 that you cannot do on the CX3400 to compensate for Baffle Step?

**Dennis H** · 04 March 2007, 20:59 Sunday

Bottom line, with all these expensive drivers, amps and crossovers, it's worth spending a bit to get some measurement gear. Once you know how your speakers actually measure in your room, you can make some intelligent choices about how to do the crossovers. Without that, you're pi$$ing in the wind.

**ThomasW** · 04 March 2007, 22:14 Sunday

Baffle step compensation is a form of EQ, it's usually built into a passive crossover....

http://sound.westhost.com/bafflestep.htm

The CX series are only crossovers, they have no EQ functions, therefore they can't create BSC.

**Habs4life** · 04 March 2007, 23:38 Sunday

Originally posted by ThomasW

The CX series are only crossovers, they have no EQ functions, therefore they can't create BSC.

nor do they have an all pass filter for adding delay for the tweeter.

**|Tch0rT|** · 05 March 2007, 04:37 Monday

Originally posted by ThomasW

For the best sound quality, home audio systems unlike car audio systems requires things like baffle step compensation, zobels (impedance compensation) and custom crossovers designed specifically for the baffle the drivers are mounted. These things aren't obtainable from a generic active crossovers.

I had thought that even home audio people generally hold an active crossover system to be superior to passive and that passives can "color" the sound somewhat. What about the Behringer DCX2496 as cjd sugests (and yes I know this is 3 way so I would have to modify my design)? If I upgrade to that will I be better off?

Originally posted by ThomasW

In home audio 8" drivers aren't really "subwoofers", since they simply can't move enough air to adequately reproduce the low bass in DVD soundtracks.

I know 8" aren't "real" subs but four of them technically can displace as much as a single 15". But I'm sure they lack the lower end that a single 15" can reproduce.

I have an open mind and I would be open to looking at different designs. I just wanted to throw out my current idea to see what other people thought since I'm new to building my own home system. In a car though I'm confident but home audio and car audio are apples and oranges hehe.

I can probably get about $1000 or so for my car equipment. I'm looking for something with good SQ that can get loud when called upon. I would like a subwoofer (I prefer them integrated into a tower but I guess I could go with the usual cube in a corner) with an amp. My reciever can support speakers as low as 6ohms (so I don't think the Natalie P's are an option...). If you can't tell I'm partial to active systems but I take it they are frowned upon as far as home audio goes on this forum.

Any sugestions?

Thanks!

Ryan

**ttan98** · 05 March 2007, 05:47 Monday

you may want to have a look at this system at this website:

404 Not Found

http://www.audiocircle.com/circles/index.php?topic=37959.0

The system has a number of advantages:

1. The drivers are relatively cheap compared to the well known ones
eg. Vifa Seas etc

2. It will sound very loud and project a large image and sound stage- guarranteed.

3. The person, Danny owner and designer who sells the drivers will even help you in the design, esp., x-overs, cabinet size, etc. He understands the capabilities of his drivers very well.

I have no interest in the company, GR research by the way. I may even buy his drivers in the near future.

Good luck...

**|Tch0rT|** · 05 March 2007, 09:22 Monday

Thanks for the link ttan98!

I've heard of GR Research before. I kinda forgot about them. Anyway The OB-7 kit looks like it's up my alley. I might have to look into it some more.

Ryan

**cjd** · 05 March 2007, 10:35 Monday

*cough*

Well, let's just say I wouldn't have pointed you there.

You worry that passive crossovers can color the sound... so can/do active. Do does ANYTHING you put in the signal path, at least have some potential. Long speaker run? It'll increase series impedance, raise Q on your box. If it's capacitive or inductive in any significant amount it'll do more than that.

I've heard the DCX in a top shelf design with Seas Millenium components, and was very much underwhelmed. The designer is very much competent - had I not also heard a direct comparison of a passive crossover (by Dennis Murphy I believe) with one implemented in the DEQX (top shelf digital crossover) I would have been more confused. The passive was far and above the best in its ability to resolve detail. The DCX powered system literally lost an entire violin section trying to render a portion of Mahler's 8th. The Ellis 1801 handled it just fine...

On 8's vs that single 15: it's not about diameter alone, it's about swept volume. Fs also plays a role. I mean, the Adire Extremis (7") can hit some VERY low tuning and do it with authority, so 8's aren't impossible to work with. But not likely to hit 10Hz too well. 25Hz, sure.

C

**|Tch0rT|** · 05 March 2007, 13:47 Monday

Originally posted by cjd

*cough*

Well, let's just say I wouldn't have pointed you there.

LOL! Yeah there seems to be somewhat of a rivalry between this forum and that forum. To be honest though I feel a bit of Snake Oil Voodoo vibe from that forum. I'm not one to subscribe to using multi-thousand dollar 3ft inter-connects, speaker wire, nor silly little "audiophile" wooden blocks, etc.

Originally posted by cjd

You worry that passive crossovers can color the sound... so can/do active. Do does ANYTHING you put in the signal path, at least have some potential. Long speaker run? It'll increase series impedance, raise Q on your box. If it's capacitive or inductive in any significant amount it'll do more than that.

I've heard the DCX in a top shelf design with Seas Millenium components, and was very much underwhelmed. The designer is very much competent - had I not also heard a direct comparison of a passive crossover (by Dennis Murphy I believe) with one implemented in the DEQX (top shelf digital crossover) I would have been more confused. The passive was far and above the best in its ability to resolve detail. The DCX powered system literally lost an entire violin section trying to render a portion of Mahler's 8th. The Ellis 1801 handled it just fine...

I personally don't know, but there seems to be the Active vs. Passive camp. From my experiance with car audio I tend to prefer active, at least in that environment I do, so much in fact that I will NEVER use a passive system again in a car if I can help it. Though in home audio I keep and open mind. But I will say that I will have to do a tried and true design to go with passive as I do not have the time or resources to tweak a passive over or the experiance to do so either. This is a very interesting learning experiance so far.

Originally posted by cjd

On 8's vs that single 15: it's not about diameter alone, it's about swept volume. Fs also plays a role. I mean, the Adire Extremis (7") can hit some VERY low tuning and do it with authority, so 8's aren't impossible to work with. But not likely to hit 10Hz too well. 25Hz, sure.

C

I'm not concerned about output at 10hz. Only because I have a wife and neighbors. LOL! The instant I knock something off a shelf or give her reason to believe the neighbors heard the bass I know I'll get some sort of speach on how my speakers are obnoxious. The only difference she can tell with speakers is that some are louder than others. She does not hear any difference in clarity or detail. She's quite content with Cerwin Vega bookshelf speakers.

cjd, can you point me to some nice designs in my budget?

Thanks,

Ryan

**cjd** · 05 March 2007, 14:35 Monday

Originally posted by |Tch0rT|

LOL! Yeah there seems to be somewhat of a rivalry between this forum and that forum.

Any rivalry is one-sided. There is definitely a difference in methodology and some other stuff. I don't think you're going to find anyone here will do much more than QUESTION - i.e. seek for answers. And you may be surprised where there are agreements.

I personally don't know, but there seems to be the Active vs. Passive camp. From my experiance with car audio I tend to prefer active, at least in that environment I do, so much in fact that I will NEVER use a passive system again in a car if I can help it.

Yes, well... how much do you understand about the math, about the physics? Putting together passives is not usually just turning dials and flipping switches. Actives aren't always either but I think THAT is why they're preferred.

Passives require measurements. Good, accurate measurements. And an understanding of the science (physics more than the math, there are tools to take care of the math for you).

We're not against active crossovers at all, by the way. There are definitely times and places for them.

I'm not concerned about output at 10hz. Only because I have a wife and neighbors. LOL! The instant I knock something off a shelf or give her reason to believe the neighbors heard the bass I know I'll get some sort of speach on how my speakers are obnoxious. The only difference she can tell with speakers is that some are louder than others. She does not hear any difference in clarity or detail. She's quite content with Cerwin Vega bookshelf speakers.

Oh, then you want to ignore 30-50Hz. 10Hz should be fine, you can shrug and have no idea what she's talking about.

Grab yourself a Thigpen rotary sub and go to town!

I have a wife and neighbors. They only complain if I play TOO LOUD. So do my ears, crazy as that seems. A quality system does everything you want it to do but doesn't require 100dB levels. Or even 90dB levels (very often). I often listen to music at <60dB average.

As for something in your budget: You say you want a sub, and yet above you mention not wanting actual sub-bass.

I might recommend you take a peek at the Behringer A500 + the RS TMWW 3-ways. The Exodus 641 or 2641 might also be worth a gander. Just off the top of my head.

C

**Dennis H** · 05 March 2007, 14:57 Monday

I think it's easier to get something 'listenable' with a simple active box than with passive components using textbook formulas, assuming you don't have any measuring gear and are tweaking by ear. But to get a 'great' speaker, either active or passive, you have to measure the drivers and design a custom crossover/EQ that includes the drivers' measured response. Here's an active crossover done right -- not for the faint of heart.

Crossover/EQ

http://www.linkwitzlab.com/xo_eq.htm

PHOENIX, equalizer, circuit, electronic crossover, remote volume, tilt control, power amplifier, LM3886, power supply

**ttan98** · 05 March 2007, 19:23 Monday

A passive x-over correctly designed and implemented will probably sound better than an active x-over. Infact the component cost for the passive components are not cheap, they can amount to hundreds of dollars. Besides it takes many hours of design, testing, listening and tweaking before you can arrive at a final design. If you have the time and resources go ahead esp if you do not much experience in designing x-over like myself. Designing a x-over is more an art than a science, or viewing it differently starts off as a science and tweaking it makes it an art form.

On the other hand an inexpensive DCX2496(about USD$259) will do the job quite well with minimun of fuss, of course it takes some time to learn how to drive the unit. Besides there is an upgrade for the unit you many want to consider at a later stage. This unit can be reused if you decide to make another set of speakers, while the passive x-over is fixed and only certain components are reuseable, futhermore more time is spent on redesigning the x-over again. personnally I will buy this unit at a later stage.

One person who owned a commercial set of speakers made a comparison at a detailed level even to reshaping the passive x-over on the DCX and his conclusion was the passive sounds more musical. He sold his DCX in the end.

There you are decision, decision......

**cjd** · 05 March 2007, 22:00 Monday

The DCX simply loses low level detail - there's a LOT that includes that is really crucial for some things, and totally unimportant for some things.

If you listen to metal, electronica, it probably doesn't matter. if you listen to acoustic/ensemble music (classical, jazz) it's going to be something you *can* hear (but whether each of you is able is harder to say - I've essentially got a full life of classical training).

**|Tch0rT|** · 06 March 2007, 03:00 Tuesday

Originally posted by cjd

Yes, well... how much do you understand about the math, about the physics? Putting together passives is not usually just turning dials and flipping switches. Actives aren't always either but I think THAT is why they're preferred.

Passives require measurements. Good, accurate measurements. And an understanding of the science (physics more than the math, there are tools to take care of the math for you).

I don't understand the math at all really. Though I haven't exactly tried to learn it either really. This is probably partially why I prefer active.

Originally posted by cjd

We're not against active crossovers at all, by the way. There are definitely times and places for them.

What is their time and place for them? Other than sub woofer duty that is.

Originally posted by cjd

As for something in your budget: You say you want a sub, and yet above you mention not wanting actual sub-bass.

I might recommend you take a peek at the Behringer A500 + the RS TMWW 3-ways. The Exodus 641 or 2641 might also be worth a gander. Just off the top of my head.

LOL I realized what I said about the sub right after I posted it but I was too tired to bother changing it. To be a little more clear; I want a sub, but output to 10hz really isn't a goal. Mostly since it's in-audible and frequencies that low tend to shake things. 10hz is fun in a car while watching how liquid reacts to it but in a home I don't really see a use for it other than a little extra omph for explosions in movies. My wife gets all upset when she feels the couch shake, but when she's gone I wanna rock the house muahaha. It sure sucks in a way to married to someone who has no interest/care about sound quality... funny how she's a movie nut but doesn't want the "movie" sound. :M

I looked at a few of those designs and then some. The Seas/Dayton RS TMWW with an active sub sounds like it's right up my alley. Will the TMWW run well with the 85 watts my reciever outputs @ 8ohm?

Thanks,

Ryan

Possible 1st DIY, 4 way active TMWSS tower

Possible 1st DIY, 4 way active TMWSS tower

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment

Comment