With time on my hand I am dusting off some old projects.
Like my Eminence OB project. I'm using a Eminence Beta 12LTA plus tweeter and two Eminence Alpha 15A per side. And will be using two Icepower 125ASX2 amplifiers
I know this I done many many times and still I have question. In his paper MJK uses a 9mh coil and 68uf cap for the one Alpha, I am using two, so I searched for filter solution but almost everyone uses an active crossover or MiniDSP which I don't have.
Has some of you got an (cheap...) idea for a passive crossover?
Ps, I do have a third amplifier if necessary....
Raymond
Like my Eminence OB project. I'm using a Eminence Beta 12LTA plus tweeter and two Eminence Alpha 15A per side. And will be using two Icepower 125ASX2 amplifiers
I know this I done many many times and still I have question. In his paper MJK uses a 9mh coil and 68uf cap for the one Alpha, I am using two, so I searched for filter solution but almost everyone uses an active crossover or MiniDSP which I don't have.
Has some of you got an (cheap...) idea for a passive crossover?
Ps, I do have a third amplifier if necessary....
Raymond
Connect them in parallel and use 4.5mH coil and 136ish uF cap. Use single amplifier for bass and set the attenuation between bass and mid-hi section with amps.
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Do you already have the 9mH inductor? It's worth trying that alone. I've done similar when using 2 GRS 15" per side on OB.
Zvu's values will get you to where Martin King placed them for 8 ohms. A lot of other things will change when you go from one woofer per side to two.
this changing is the problem. This could be reason why people use mini dsp or active filtering. I wanted to go passive first before I buy dsp or active.
Could Pllxo be a solution?
It can be a very nice solution but I would recommend you the usage of a DSP.
It's not that expensive and you don't need an extra buffer for your ICEpower modules.
Even if you go the active way I would also recommend you to flatten the impedance of your speaker with a Zobel.
The ICEpower prefer a steady resistance else they start to distort
And the sound gets annoying.
A DSP is more versatile and can be used for other projects.
Passive components especially for woofers are usually very expensive and since you already have the amps go the active way 😉
It's not that expensive and you don't need an extra buffer for your ICEpower modules.
Even if you go the active way I would also recommend you to flatten the impedance of your speaker with a Zobel.
The ICEpower prefer a steady resistance else they start to distort
And the sound gets annoying.
A DSP is more versatile and can be used for other projects.
Passive components especially for woofers are usually very expensive and since you already have the amps go the active way 😉
It would do the job but I don't have experience with this model. I own the HD version. In the past some users complaint about noise from the 2x4. With the HD version I don't have any trouble. Works like a charm 🙂
DSP can be fast and flexible, which is why a lot of people use it. I have not had good luck with DSP and open baffle speakers, passive always worked better for me. I have done well with DSP on other types of speakers.
Some years ago John Busch had an open baffle set up with 2x18" Eminence woofers, 1 beta 12LTA and 1 tweeter per side. Sounded amazing. The beta 12LTA made a better midrange than I would ever have imagined.
Maybe John can chime in with some words of wisdom.
Some years ago John Busch had an open baffle set up with 2x18" Eminence woofers, 1 beta 12LTA and 1 tweeter per side. Sounded amazing. The beta 12LTA made a better midrange than I would ever have imagined.
Maybe John can chime in with some words of wisdom.
Dusting even more old projects of I have 6 L15D pro amplifiers?? Unfortunately I don't have the power supplies... What was I thinking??...
I don't have the original values for the crossover lying around... I did see that the MiniDSP is on sale... €99.. That is quite a bit cheaper than I thought and cheaper than some of the coils I have searched for..
I don't have the original values for the crossover lying around... I did see that the MiniDSP is on sale... €99.. That is quite a bit cheaper than I thought and cheaper than some of the coils I have searched for..
The mini dsp 2x4 is a great affordable unit. The 2x4hd adds usb audio input. IMO that alone is worth the extra cost.
XERXES 75 In order to realize the potential of the drivers you intend to use there are a few significant issues that need to be dealt with. As with all Open Baffle - shallow cardioid designs, one needs to factor in how the main baffle is going to effect your woofer(s) performance. This especially true when a passive woofer low pass crossover is used. Baffle dimensions, wings (if any) and surface area all come together to set maximum potential efficiency, low frequency cut off potential and how much low frequency equalization will be required to deliver a flat response down to woofer resonance.
What are your baffle plans at this point in terms of dimensions and shape? Once that is known, things get a LOT easier crossover wise. J
What are your baffle plans at this point in terms of dimensions and shape? Once that is known, things get a LOT easier crossover wise. J
That's an interesting comment about DSP not working well with open baffle speakers and causes me some concern, since that exactly the path I'm about to embark on. Have you been able to figure out why. I'd would really like to hear more. Thanks,
It could have been my conventional thinking when using DSP on open baffle. DSP should be able to do it, but I had a hard time getting good results. Whereas a big inductor on the woofer with some caps and resistors on the tweeter seemed to fall into place and sound right much faster.
Open baffle speakers crossovers are different and getting the right tonal balance and blending between parts isn't like a box speaker. Even tho I might throw a lot of EQ at an open baffle in an active setup, it never gelled like the passive crossover did.
Perhaps thinking in a subtractive way, like a passive crossover, would help get better results via DSP. I wish I had a better answer.
Open baffle speakers crossovers are different and getting the right tonal balance and blending between parts isn't like a box speaker. Even tho I might throw a lot of EQ at an open baffle in an active setup, it never gelled like the passive crossover did.
Perhaps thinking in a subtractive way, like a passive crossover, would help get better results via DSP. I wish I had a better answer.
Part of the deal is that series inductors found in passive low pass filters increase the Q of the driver being, well, low passed. As in the woofer section. With OB added Q is usually your friend. Also true in the mid range (for 3 way designs) assuming it (the crossover) will use an inductor to roll off the mid range at the top of its range. Inductors do act as sort of a mechanical filter removing high frequency hash that seems to get through electrical (DSP) filters. Can some times see that on an "O" scope. Suspect the "hash" is a form of switching and other distortions produced by the DSP circuity. There are time delay things going on with a big inductor too. Also, an inductor acts as a buffer relative to the amplifier. Provides a steadier, well lets say a more consistent load. Less frequency dependent as you go down in frequency. And there seems to be other factors that I do not have a clue about. Just my $0.02 worth accumulated over 60 years of experience.
This information from the two of you is very interesting and timely. What do you think of the idea to use the miniDSP to at least get the type of crossover (LR2, etc.) and its slopes worked out, and then convert that design into a passive implementation. Or is it just as easy to start with a good crossover design program and skip the DSP idea altogether.
Well I did a lot of crossover prototyping with DSP and active. For me it was the fastest way to get to a good result.
However with OB it was not so easy as I did not find that my active OB filters translated well to passive. With box and horn speakers I had much better luck using active crossovers and EQ to prototype.
John literally has buckets full of crossover parts. Actual buckets. And he's been building open baffle speakers since at least the Johnson administration, so he can get something up and running very fast. 😀
Let John know what your doing and he can likely guide you to a good starting point. The fact that he already built a 2 woofer + LTA + tweeter OB rig is stroke of good luck. IIRC, the tweeter crossover was not easy.
However with OB it was not so easy as I did not find that my active OB filters translated well to passive. With box and horn speakers I had much better luck using active crossovers and EQ to prototype.
John literally has buckets full of crossover parts. Actual buckets. And he's been building open baffle speakers since at least the Johnson administration, so he can get something up and running very fast. 😀
Let John know what your doing and he can likely guide you to a good starting point. The fact that he already built a 2 woofer + LTA + tweeter OB rig is stroke of good luck. IIRC, the tweeter crossover was not easy.
So are you suggesting that even crossover simulator software does not work well for OB speakers and the only real way to make a crossover is by trial and error with a bucketful of various components.
Also, I'm not trying to do the 3-way that's been discussed. Just a simple 2-way with a full range and large woofer.
Also, I'm not trying to do the 3-way that's been discussed. Just a simple 2-way with a full range and large woofer.
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