Well, I've no experience working with the thing, so I can't give first hand information, but I've heard some people raise concerns that the behringer gear is not up to 'audiophile standards' in terms of DACs and other components used. Usually those who raise these issues recommend moving up to some similar piece of gear by a more 'reputable' company that costs 10x as much.
For someone like me, who is happy with consumer grade mid-fi electronics (for the most part), these things are not a major concern. For someone with $1000 outboard DAC or CD transport and a $2000 tube amp, these may be real concerns. I suppose its a matter of priorities and budgets.
kfr01 said:
Well, in a MTM design, the woofer interact, and the interference will not sound very nice. So the crossover needs to be as low as possibe. D'Appolito states about 3/4 of the wavelength of the distance between mid and tweeter (measured from the middle). In most designs still cross a litte higher, but 1x wavelength should me a good starting point. A MT design does not have this problem. But you should also consider the off axis response of the woofer at the X-over point.
The Behringer 2496 looks nice. You can even hook up a mic. Look on ebay, they might have one at a low price...
4real said:
Hmm.. alright. Let me make sure I understand this. Say the center of the mid and tweeter in an MTM config are 6" apart then the frequency with that wavelength is 2250hz. 3/4 of that is around 1700hz. So, if I wanted to use this setup then the tweeter would need to be able crossed over at 1700hz?
That seems low. Maybe I will just go with one Extremis 6.
So, my latest plan is a too be determined tweeter, hopefully crossed from 2-2.5khz, one extremis 6, and a shiva.
kfr01 said:
In that thread they talk about the Seas TDFC, which I have heard good things about also. Generally, ribbon and planar tweeters can play lower, but you have to worry about power handling since they're usually more fragile in that respect. So the Seas could be a thing to look into, look at John's site for some more info about it and the TFFC: http://home.new.rr.com/zaph/audio/
Plus its only like $20-something.
Where in IA are you? There is a DIY meet in Altoona next saturday.
kfr01 said:
Thanks for the into on that tweeter. I'm also in the Iowa City area. (trying to solidify some diy plans before Reference AV opens their new showroom close to my home in Coralville)
Oh yeah, my friend told me about that place. He has a Behringer Ultracurve EQ and crossover that is modified to work in his car. He's using it as a 4-way with an EDi set and a TB in the middle and a trio of eD 10o's. I trimmed my car stereo down a lot so I'm down to a 2-way active using TB W3-871S and some 6.5" in the doors on a Tru T4.65.
Firstly here is a nice looking system based on the Behringer Ultradrive:
Digital active speakers
Now a few different ideas.
TMW + sub
Vifa XT tweeter
CSS - 4.5" widerange driver with XBL2
Adire Koda - (80 - 300 Hz)
Starting with the Vifa XT tweeter which you seem to like. Some have commented that this tweeter acts a bit like a midrange driver and rolls off a lot lower, but it lacks the SD to work well down in that range. As a result it tends to sound harsh unless crossed higher than other 1" tweeters. It seems with a passive xo many use a 3rd order slope at 2.8k. With a digital xo and an 8th order 48db slope it should perform well and handle being crossed lower.
The CSS widerange driver has low distortion and is very flat, easier to deal with than the Extremis. It gives you the flexibility to cross where you prefer rather than force you to cross lower than the tweeter can handle. It's off axis response is probably much better as well - in fact very good off axis response up to 3k. With its high xmax it would have a very high power handling when crossed at 300 Hz.
The Adire Koda is only slightly more expensive than the extremis but due to the larger SD is equivalent to ~ 2 of the extremis. The response of this driver is interesting - it is as if it has BSC built in. In Adires words it is an "... ideal driver for bridging to a subwoofer in the 50-80 Hz range, and crossing over to a midrange in the 300-600 Hz range."
If budget allows I would then cross to the Adire Tumult, or consider it a future upgrade. For high output I'd cross at 60 - 80 Hz to help the rest of the system keep up with the Tumult.
Most diy speakers are simple but difficult. Say a 2 way speaker with a passive crossover - it's quite simple, but not easy to get right. If you used the XT tweeter here, it is quite fussy about the xo point and slope. This speaker is not as simple, but it is not as difficult. There are two things to consider here - complexity and difficulty. I would argue that adding a digital or active crossover increases the complexity of the project, but also reduces the difficulty.
With the ultradrive the drivers would all be very linear and perform well within their range. Also you can easily try different crossover slopes and xo points. The nice thing about this project would be to have all the drivers (except the tweeter) using the XBL2 technology with very low distortion and a very flat BL curve.
Here's a pic of what it might look like .... (hmmmm I'm getting tempted to do something like this myself now!!!)
Digital active speakers
Now a few different ideas.
TMW + sub
Vifa XT tweeter
CSS - 4.5" widerange driver with XBL2
Adire Koda - (80 - 300 Hz)
Starting with the Vifa XT tweeter which you seem to like. Some have commented that this tweeter acts a bit like a midrange driver and rolls off a lot lower, but it lacks the SD to work well down in that range. As a result it tends to sound harsh unless crossed higher than other 1" tweeters. It seems with a passive xo many use a 3rd order slope at 2.8k. With a digital xo and an 8th order 48db slope it should perform well and handle being crossed lower.
The CSS widerange driver has low distortion and is very flat, easier to deal with than the Extremis. It gives you the flexibility to cross where you prefer rather than force you to cross lower than the tweeter can handle. It's off axis response is probably much better as well - in fact very good off axis response up to 3k. With its high xmax it would have a very high power handling when crossed at 300 Hz.
The Adire Koda is only slightly more expensive than the extremis but due to the larger SD is equivalent to ~ 2 of the extremis. The response of this driver is interesting - it is as if it has BSC built in. In Adires words it is an "... ideal driver for bridging to a subwoofer in the 50-80 Hz range, and crossing over to a midrange in the 300-600 Hz range."
If budget allows I would then cross to the Adire Tumult, or consider it a future upgrade. For high output I'd cross at 60 - 80 Hz to help the rest of the system keep up with the Tumult.
Most diy speakers are simple but difficult. Say a 2 way speaker with a passive crossover - it's quite simple, but not easy to get right. If you used the XT tweeter here, it is quite fussy about the xo point and slope. This speaker is not as simple, but it is not as difficult. There are two things to consider here - complexity and difficulty. I would argue that adding a digital or active crossover increases the complexity of the project, but also reduces the difficulty.
With the ultradrive the drivers would all be very linear and perform well within their range. Also you can easily try different crossover slopes and xo points. The nice thing about this project would be to have all the drivers (except the tweeter) using the XBL2 technology with very low distortion and a very flat BL curve.
Here's a pic of what it might look like .... (hmmmm I'm getting tempted to do something like this myself now!!!)
Attachments
Another thing to consider is the power required to each driver, which is affected by the way the bandwidths are divided.
Power bandwidth table
With crossover points of 250 Hz and 2.5k you need approx:
25% of total power to the tweeter
35% mid
40% bass
So to get the equivalent of a 200w amp you need:
50w tweeter
70w mid
80w bass
Considering the losses in a passive system you may in fact only need not much more than half that, or if you had that much power, you could just have a bit more headroom.
In practise the bass needs more power as bass tends to be more dynamic, so this might be more suitable:
20w tweeter (a diy class A amp would work just fine)
40w mid
150w bass
This is assuming the efficiency of the drivers is matched. Now this is where things get more complicated, as if you don't get this right, you can end up changing the crossover points!
I suspect a plate amp would control a woofer like the Koda better than a Rotel receiver, which is also probably lacking in power if you want the Koda to extend below 80 Hz.
I recommend having a look at this ESP article on biamping and browing through other related articles on the site. Very good info!
You may also find active analogue crossovers of interest. You dont' have the same flexibility and power but it is cheaper and many consider it a more transparent option.
Power bandwidth table
With crossover points of 250 Hz and 2.5k you need approx:
25% of total power to the tweeter
35% mid
40% bass
So to get the equivalent of a 200w amp you need:
50w tweeter
70w mid
80w bass
Considering the losses in a passive system you may in fact only need not much more than half that, or if you had that much power, you could just have a bit more headroom.
In practise the bass needs more power as bass tends to be more dynamic, so this might be more suitable:
20w tweeter (a diy class A amp would work just fine)
40w mid
150w bass
This is assuming the efficiency of the drivers is matched. Now this is where things get more complicated, as if you don't get this right, you can end up changing the crossover points!
I suspect a plate amp would control a woofer like the Koda better than a Rotel receiver, which is also probably lacking in power if you want the Koda to extend below 80 Hz.
I recommend having a look at this ESP article on biamping and browing through other related articles on the site. Very good info!
You may also find active analogue crossovers of interest. You dont' have the same flexibility and power but it is cheaper and many consider it a more transparent option.
paulspencer said:
Thanks for the great replies! I do like the idea of using as much XBL2 as possible. That 4.5" looks like it would fit the bill. Maybe I'm a sucker, but after reading the material on adire's site they sold me on that technology. I also have to say I like the idea of adding the Koda 8 back into the mix. It seems like it might add some otherwise lacking 'punch' and midbass finesse.
Would you elaborate on this step? Assuming I use the Behringer, what steps would I need to take to correct for this?
Also, on the link you sent me the man showed and briefly mentioned an attenuator he made for the Behringer's outs. He mentioned that the pro-sound outs were too strong. Do you know if this step is necessary?
Thanks again!
kfr01 said:
I think it makes sense to have XBL as much as possible. And I would certainly not leave it out of the bass! I think this is where Adire have a very significant "point of difference." Their drivers using XBL for the midrange perform well, but there are already drivers that do this successfully. It appears to be what they have done with subs that is most impressive. If you are going to spend the money on Ultradrive and the amps to go active, then you might as well go with XBL drivers for the bass and sub bass as well.
There are other drivers which show their BL curve - see the Dayton Titanic and DVC on the Parts Express website. It appears to perform quite well although the DVC doesn't look so good if I recall. The Shiva is probably very similar.
If you budget doesn't allow for the Tumult, then a pair of Koda drivers should perform quite well for a while. They would not be that far off the SPL of the Shiva, but they would have lower distortion. If you use them in the way I suggested then the real sense of power and punch would come from the Tumult. I'd call 40 - 60 Hz or so the midbass punch.
In fact, if you are using the Tumult then I would suggest using it as high as you can! (actually my guess is that 60 - 80 Hz would work well) There shear output, authority, performance and low distortion of this driver is amazing. (I have heard it).
kfr01 said:
This is where I suggest you have a look at the article on bi-amping! Yes it is a long read, but it will explain this. Basically you have to deal with different speaker sensitivities with the gain of the amplifiers. You would think that you could just adjust the gain on the active filters, right? ... but if you do this, the crossover point will also be shifted. It's shown in the article and here is a pic to explain:
An externally hosted image should be here but it was not working when we last tested it.
Suppose you have a bass driver with 2db less sensitivity. You need 2db more gain to that amplifier to compensate for this. Every amp has a gain ... eg. 28db.
If there is another way to deal with this, I'm not aware of it. Perhaps some others can shed some more light on the subject, or suggest some ways of dealing with this.
kfr01 said:
I haven't used Ultradrive and Luc knows more about it than I do.
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