[lsiberian]

This is getting interesting.
I want to think the sugestions already made.

lsiberian in fact I have readed those informations about bi-amping. But sometimes I miss some points.

I'm just going to discuss the disavantages.
1- If I go the bi-amp way, I would save money from one amplifier (aprox. 200 €). Great. But, I will need to spend on the passive crossovers. Maybe 80 € for both. That saves me 120 €. Also I will be loosing 2 outputs on the DCX, right?
I agree that 120€ is a considerable amount of money, with that I can almost build the rear speakers for a 5.1 system. But also look at this, I'm young, and certanly I will want to do more teaking and some upgrades in the future, going tri-amp (or 3 way fully active) I'm not going to loose the money spent on the passive crossovers. But I'm still considering any reasonable option.

2 - I completly agree that "one amplifier with twice the power versus two amps of half the power biamped is less likely to clip"

3 and 4 - I make JCD my words.

JCD by your comments I assume that you encourage the 3 way full acive, right?

Please, lsiberian and JCD (and others), don't be affraid to discuss more issues, better now then later when money is spent.

1. Not sure how you are getting that a passive crossover is going to cost you 80 euros. Most can be assembled for far less.

2.You can still manipulate the entire sound of your system with the DCX. You'd be giving yourself the ability to hook up your subs to the DCX. Meaning you could have a 4-way setup with the subs fully eqed.

3. Fully active is just as time consuming as making a 2-way upper module filter. I"m not talking about passive between your bottom driver and the top. Only between the tweeter and the midrange.

4. Don't forget that XLR cables aren't cheap either.

Ultimately the choice is yours.

But I would encourage to at least give the passive crossover a go. If anything it will be a valuable learning experience.

If this is your first project I still suggest you start with a simple 2-way build before you undertake this beast. I don't think stepping into this as your first project is wise. There is a lot to learn that you will want to get before you build your longtime main speakers.

Either way make sure you treat your cabinets with fiber or rockwool and that you brace the out of them.

 

[JCD]

1. Not sure how you are getting that a passive crossover is going to cost you 80 euros. Most can be assembled for far less.

2.You can still manipulate the entire sound of your system with the DCX. You'd be giving yourself the ability to hook up your subs to the DCX. Meaning you could have a 4-way setup with the subs fully eqed.

3. Fully active is just as time consuming as making a 2-way upper module filter. I"m not talking about passive between your bottom driver and the top. Only between the tweeter and the midrange.

4. Don't forget that XLR cables aren't cheap either.

Ultimately the choice is yours.

But I would encourage to at least give the passive crossover a go. If anything it will be a valuable learning experience.

If this is your first project I still suggest you start with a simple 2-way build before you undertake this beast. I don't think stepping into this as your first project is wise. There is a lot to learn that you will want to get before you build your longtime main speakers.

Either way make sure you treat your cabinets with fiber or rockwool and that you brace the out of them.

1. Totally agree.. but I think you can also argue it could be a lot more depending on quality/expense of the various parts. I've designed a passive crossover that had a three inductors, 4 caps and a couple of resistors. The part cost for that ran ~$55/speaker or $110 for a pair. Granted this crossover did have a notch filter and a zobel network in addition to the 2nd order LR crossover, but I wasn't going crazy with my cap selection
3. My opinion is a little different. It's not a ton faster, but some. Not having to deal with how the impedance curve of the different drivers might effect the crossover I think is a time saver. Also, if you want to try a different crossover point, you don't have to redesign, reassemble, etc the passive crossover.

I think lsiberian makes some good arguments, and I certainly don't want you to ignore his advice/suggestions or think that I'm trying to portray him in any way negative -- these kind of point/counterpoint arguments can come across that way online.

And I do agree with lsiberian on his other points:

• designing a passive crossover is a great experience and you will learn a lot. I've done one now and enjoyed the process a lot. If you're going to continue this hobby going forward, then this is an invaluable exercises.
• if this is your first project, I think building a simple 2-way would be a great idea

 

[Zeverin]

Hi. I'm short on time right now, but lsiberian and JCD are exposing very valid and wise arguments.

You know what? I will follow the 3-way aproach, BUT, not without trying the use of a passive crossover, just to learn a bit more, and see by myself the diferences both in sound and work involved, and also the results :nerd:.

I have built a few subwoofers, and also passive (2 way and 3 way) crossovers. Also in the last years I have been reading alot about loudspeakers design and construction. I know this is going to be hard, but I belive that I'm skilled enough to acomplish this project, even if it takes some time. This is a small beast I want to build. The enclouse shape will also represent one challenge by itself :coocoo:.

Latter I will comment some of yours arguments.

I think lsiberian makes some good arguments, and I certainly don't want you to ignore his advice/suggestions or think that I'm trying to portray him in any way negative

Of course not, and neither I, he is being very helpfull. Thank you. :bigsmile:

 

[Zeverin]

I posed this question to someone I know that has the technical backround to address this point -- his contention is that a 200 watt with a full range signal is more likely to clip than two 100 watt amps with an active crossover between them. There is a thread someplace on the web that this arguement has been addressed -- if I can find it, I'll post a link. I think lsiberian addresses the issues in most real world examples by actively crossing the <250hz signals, but I really don't think this is going to be an issue if you've got ~50 watts for the tweet and ~80 watts for the mid. , the tweet probably can't even handle a sustained 50watts.. but I digress.

Are you refering to this: http://sound.westhost.com/bi-amp.htm see point 1.4 Actual vs Effective Power ?

 

[Zeverin]

1. Not sure how you are getting that a passive crossover is going to cost you 80 euros. Most can be assembled for far less.

Maybe it is too much. 60 euros is more reasonable for the 2 crossovers.

2.You can still manipulate the entire sound of your system with the DCX. You'd be giving yourself the ability to hook up your subs to the DCX. Meaning you could have a 4-way setup with the subs fully eqed.

This is a good solution to fully use the DCX flexibility.

3. Fully active is just as time consuming as making a 2-way upper module filter. I"m not talking about passive between your bottom driver and the top. Only between the tweeter and the midrange.

You are right, it still takes a lot of time. But with one active system like this you can try diferent crossovers point and slopes and see what works best in the room :innocent:

4. Don't forget that XLR cables aren't cheap either.

Yes, unfortunately very true :thumbsdown:

But I would encourage to at least give the passive crossover a go. If anything it will be a valuable learning experience.

A very valuable experience. I will follow the 3 way fully active path, but I will take into consideration your advice and try it also, just to learn a bit more.

In a few days I will have the cabinets modeling completed, then I will share you you.

 

[mayhem13]

Zeverin, going with a fully active system for your first system when considering a three way is a sound idea and given the cost of amplification, a very cost effective one since the DCX will already be available. Since you're in Portugal, i would strongly suggest you consider locally available drivers from european manufacturers. For Midrange drivers, there's FAR better choices available to you than the Dayton Reference series and high efficiency Pro Audio 10" woofers would allow for a much more efficient system with no need to pad down the MT section to match. There's a lot of excellent work being done with Pro drivers as you've read with B&C, Beyma and Faital Pro showing ultra low HD at higher output levels that HiFi drivers just can't match. Given the availabilty of the TC sub already, it stands to reason that 60hz of extension is all that's needed for the bottom end of your system.....something a 10" Pro woofer can easily do in a relatively small enclosure as compared to the RS270 and given local purchase as opposed to import, equally cost effective. For matched efficiency, look at some of the high efficiency 1" domes available. The SBAcoustics SB29 comes to mind at 93.4db which measures incredibly well for $50 U.S. Mated to a Pro 6.5" high efficiency Midrange driver and crossed in the 2khz range efficiency,directivity and off axis response as well as ultra low non linear HD is hard to beat. You've got great choices of drivers right in your own back yard. I'd explore those first over the Dayton stuff. Proof is in the measurments and simply put, the Dayton RS series are nice, but there's much better options right around the corner in Spain and Italy.

 

[Zeverin]

Hi mayhem13. Thank you for the suggestions. Do you know any online stores that sell those drivers? Also can you point me some cool projects using drivers of the listed brands?
I really like the PRO stuff, but the looks!!!!:wits-end: I know that you can't have everything, but I look forward for some cool projects with PRO drivers.

 

[mayhem13]

uspeaker.com/prosoundservice.com/partsexpress.com........for US sales but given the manufacturers are right in spain and italy, i'd look in your own back yard for dealers. The sites listed will at least give you an idea of how well they perform and with some creative installation , the pro stuff looks just as good as the hifi stuff.....no bells and whistles to impress.....just the stuff that counts. For 6.5" midrange drivers look at Zaphaudio.com for test results of the 18Sound 6nd40 and the B&C 6md38 whose efficiency and low HD are unmateched in the hifi world. There's quite a few 10 and 12" woofers that are very cost effective as well and offer a level of dynamics that must be heard to be believed. Imagine a 3way capable of 60-20khz at 114db with only 100w input power...that's the dynamic range offered by these types of drivers where power compression is nearly nill in the average home environment.

 

[Zeverin]

Hi. Sorry for the late reply. I had contacted a distributor in Portugal of 18sound, and asked for the price of the 6ND430 driver. They are charging 75 €uros, that is the price of two RS150. Do you think it's worth it?

In a few days I will be posting the 3D model of the enclosures

 

[mayhem13]

Yes.......as a single 6nd is more efficient,handles more power, and plays higher before breakup than two RS180's........and has lower HD too. It won't play as low but since this is a three way it doesn't have to.

 

[Zeverin]

Well, I had been looking over and over the measures taken by Zaphaudio. And in fact the performance of the 6ND430 is trully impressive. This means that I'm going to spend the double in the midrange drivers, but the added performance (distortion and dynamics) is worth it. Thank you mayhem13 for those great advices. The only problem now, is WAF. My wife dislike the looks of the 6ND430, in fact I don't like it also, but that's not the important factor here. Soo I must convince her, wish me luck.
I havent found a replacement for the RS270, and I'm open to new suggestions. But only 10" drivers please. I like the 10W400 also from eighteensound, but I'm lacking of information about their performance. Any recomendations or information about the 10W400? I can get it for 84 €, rougly the same price of the RS270.

 

[brianpowers27]

If you ask me.. (Cost obviously isn't an issue here.) skip the dual woofers since sensitivity isn't an issue. Trade them in for a high quality sub. This will increase overall displacement as well as give you the flexibility to account for various room issues.

 

[Zeverin]

Hi bdp. Thank's for the suggestion. I'm afraid that I don't agree completely with you. If I lower the sensitivity of the woofers I need to use more power, more power equals more expensive amplifier (perhaps noisy fan cooling), and the distortion number can raise quicker (maybe, maybe not), and they "only" need to handle frequencies above 60 Hz, below 60Hz my TC 2000 15" is going to take care. I also like the idea of using a bigger surface to move gently the air, than a smaller one moving the air in a more violent manner. Those this assumption makes any sense?

 

[brianpowers27]

Hi bdp. Thank's for the suggestion. I'm afraid that I don't agree completely with you. If I lower the sensitivity of the woofers I need to use more power, more power equals more expensive amplifier (perhaps noisy fan cooling), and the distortion number can raise quicker (maybe, maybe not), and they "only" need to handle frequencies above 60 Hz, below 60Hz my TC 2000 15" is going to take care. I also like the idea of using a bigger surface to move gently the air, than a smaller one moving the air in a more violent manner. Those this assumption makes any sense?

That makes sense to me. I didn't realize you had a sub already. In that case, the high sensitivity is a benefit because you will already have lf extension.

What target listening levels are you shooting for and how much power do you have on tap?

 

[Zeverin]

I want to achieve 110 db (continuous) at 2 meters listening position from 30 Hz to 20KHz. The TC 2K can assure that extension down to 30 Hz (powered by one EP2500). The "weakest" component here is the tweeter, but with a sensitivity of 93 db, I think that is enough for me. I'm going to use 3 behringer A500. Power availability will be something like this: 200 W for woofers (2 RS270 8ohms in parallel), 200 W for mids (2 6ND430 8ohms in parallel), 120 W for the tweeter (SBAcoustics SB29 8ohms), each channel, all RMS values.

 

[Zeverin]

Here you can see the last draft I have, with the RS150 as mid drivers, not updated yet. Some changes are going to take place, than I will update the 3D model again, including other views.
I hope that you like.
I'm aware of diffraction problems with a so width baffle.

Please make some comments.

3D modeling credits to Suriv

 

[brianpowers27]

Adding a rear firing tweeter could be challenging but it has the potential to help ease the strain on your current weak link tweeter. IN theory you would have nearly twice the output.

Good luck getting the bass to sound right. It seems like you have to go sealed, due to the large airspace requirements of the rs270. This will hamper response between 30-60hz. OTOH, you will experience boundary reinforcement from the woofers that are close to the floor. I am not aware of any current tool that can simulate this boundary effect.

 

[Zeverin]

Adding a rear firing tweeter could be challenging but it has the potential to help ease the strain on your current weak link tweeter. IN theory you would have nearly twice the output.

I will leave that for future teaking, but thank you for the suggestion :rubeyes:

Adding a rear firing tweeter could be challenging but it has the potential to help ease the strain on your current weak link tweeter. IN theory you would have nearly twice the output.

Good luck getting the bass to sound right. It seems like you have to go sealed, due to the large airspace requirements of the rs270. This will hamper response between 30-60hz. OTOH, you will experience boundary reinforcement from the woofers that are close to the floor. I am not aware of any current tool that can simulate this boundary effect.

You are right, I'm shooting for sealed encloures with 150 litres. :T

 

[ktaillon]

I have a similar setup. I'm running two RS225's, one RS150 and a Peerless PL tweeter. They all run from the DCX2496 via 6 channels of amplification. The sound is very good, I'm very happy with the setup.

I think running multiple amps gives a systems better dynamics and sound. I would run all the drivers actively if you can. Plus changing around crossover setups and cross points is so fast.

I ended up using a 3rd order crossed at 350hz and 2000hz, this gave me the best sound to my ears and also the best frequency response.

 

[DrWho]

Just a few random thoughts...I'll confess I didn't read every post in its entirety.

I want to build a 3 way active system (front speakers).

Any particular reason you want to go 3-way and not 2-way?

My current ideia is to use the ULTRADRIVE PRO DCX2496 as the crossover. The amplifiers will be 3 A500 also from behringer (one for each channel).

If you're gonna go that route, then you might consider going with 3x Crown XTi:
http://www.crownaudio.com/amp_htm/xti.htm
It has a DSP built into the amplifier. They can easily be found for $300 each on the used/b-stock market.

I want the most clean and "fast" sound I can achive.

Have you thought about building some horns? It should be cheaper to achieve a cleaner/faster sound with a single driver bass horn than it would an array of four direct radiators. You get the added benefit of more control over the polar response too.

The trade off is a larger cabinet...

Why another 3rd woofer? Because of the added dinamics and lower distortion numbers at a given listening level. Any solutions?

You can always wire the woofer in series if you're worried about low impedance. When using an active crossover, you don't take any efficiency hit to balance the drivers with each other.

Btw, if you have a sub covering 60Hz and below, then I would highly recommend going 2-way.

I want to achieve 110 db (continuous) at 2 meters listening position from 30 Hz to 20KHz.

Keep in mind that 110dB continuous A-weighted still involves 20dB of crest factor in the music. If you don't want any clipping or compression, then your system will need to be capable of 130dB peaks (yikes).

A 93dB tweeter would need a 5000W peak power handling to achieve that (not gonna happen).

Btw, 110dB continuous is rock concert loud...is that really how loud you plan on listening?