R-Carpenter said:
Hi,
Nothing wrong with my reading ability. Below is a picture of your system, showing the centre speaker (an MTM on it's side). This configuration causes lobing in the upper midrange. Jnb suggested the D'Appolito xover would solve this, but TBH I'm not convinced. I don't believe a 3rd order BW would cure the lobing problem.
Dispersion from this horizontal array in this configuration would be worse than a typical 2-way, vertically oriented, due to lobing.
It's pretty much a myth that a sideways MTM will give better dispersion.
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fantfool said:
Chebyshev gives a peak before the cut, so he's using it to try to flatten response in the crossover region. Not the best approach.
Better to adust the corner frequencies and use standard passive crossover alignments to get it close. Also, looking at the response plots and trying to make those flat is pretty much useless.
MJL21193 said:
It is one of my systems.
Given the fact that most center channels are horizontally placed, I would and did chose the MTM for a reason that it is more forgiving in terms of dispersion.
In horizontally placed D’Apolitoed MTM lobbing problem will exist and the crossover will not correct it one way or another. However, it’s generally more forgiving, hence the choice. Hormonally placed MTM will not give you a better dispersion then a normal 2-way speaker located vertically.
Not everyone will be able to place a speaker over the TV set nor it’s always possible.
Fant already has a MTM center channel you think he’ll bracket it to the wall because it sounds better that way?
I can’t do it either because the walls are total crap and I’d have to bolt it through to my neighbors (don’t think they’d approve).
BTW, this MTM was custom build for this location and it is not on its side. It’s on its bottom. The sides are on the sides.
This is this MTM on its side.
Why is it useless to try to even out frequency response in the simulation? Granted, it’s not going to be the same as a real thing but you could get a pretty good idea of the outcome and then tweak it. I don’t like hoping for the best and I like to rely on measurements, not my ears. Simulations aren’t ideal and you can’t go just by simulation but it’s a great tool.
Why is it useless to try to even out frequency response in the simulation? Granted, it’s not going to be the same as a real thing but you could get a pretty good idea of the outcome and then tweak it. I don’t like hoping for the best and I like to rely on measurements, not my ears. Simulations aren’t ideal and you can’t go just by simulation but it’s a great tool.
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R-Carpenter said:
Here is an article on MTM centre channel speakers. It explains the problems.
Yes, the bottom. When an MTM speaker is talked about the picture that most people will see in their heads is the vertical arrangement. That's what I was talking about, especially considering that this speaker type performs very poorly in a horizontal position.
R-Carpenter said:
That's an MTM standing upright (on it's bottom).
Where do the response plots come from? Are the drivers installed in the enclosure? Fant remarked earlier about the lack of bass in the crossover response plots, failing to realize that these plots are not actual representations of the speakers response.
Using the simulator to get it close is fine. Fine tuning these artificial response plots (especially by using, of all things, a Chebychev filter) is useless.
In the end you have to design the filter that gets you close, build it and then adjust it by ear. You could actually measure the response (I have, when I knew something was wrong and was trying to verify the source).
In the end, it still has to sound right, no matter how it measures.
Yes I did forget because I have been accustom to looking at curves of finished speakers recently for friend. I was seeing the lack of bottom end not thinking about what the enclosure adds. My bad.
My center is MTM laying down horizontal under the tv and I don't think its a bad allignment necessarily. But we sit pretty much in front of the tv when watching HT. I do need to decide what to do with my center channel x-over though because it currently is the same as in the mains. I think I'll try the 2 mains with the new x-over and tweak before I decide what to do with the center. Frankly, I have been really thinking of going 3 way in the center and add a mid driver. But, I want to see how the mains sound first.
My center is MTM laying down horizontal under the tv and I don't think its a bad allignment necessarily. But we sit pretty much in front of the tv when watching HT. I do need to decide what to do with my center channel x-over though because it currently is the same as in the mains. I think I'll try the 2 mains with the new x-over and tweak before I decide what to do with the center. Frankly, I have been really thinking of going 3 way in the center and add a mid driver. But, I want to see how the mains sound first.
In theory, the B3 will work because the constant 90 degree phase difference throughout the crossover region will give the tilted lobing I spoke of previously. Naturally, it needs some care in design.MJL21193 said:
I'd have gone for the slight fall after 1k until 4k. The Chebychev would also happen to be unnecessary in that case.MJL21193 said:
Interesting. I wonder whether PE only offer crossover design as a starting point, as suggested.fantfool said:
I notice there isn't any phase plot(s). What did he use for phase information in designing the crossover? Was it flat? or a guess? This crossover may not be worth too much today if so...
Well I installed the PE x-overs in the 2 mains and the center. Definitely much better high mid clairity then before. I changed the tweeters to the seas tweeters from the focals along with the x-overs so I didn't listen to the seas drivers with the old x-overs. I am still getting used to the different sound.........Like I said, better clairity for sure, but maybe not as much punch on the low end as before. I think the sealed center sounds better then the ported mains, not sure why just my first impression. I have to listen to some more variety of music as well to give it a good evaluation. Over all it sounds better no doubt, my wife even remarked how much clearer it sounded.
I don't know......maybe some tweaking....?
I don't know......maybe some tweaking....?
would depend on your bas woofer
some woofers are more suited for Bass Reflex
other are specially made for Sealed Boxes
same, not all woofers are suitable for TL, transmission line boxes
it comes down to the thiele small electrical parameters
which woofer will suit best for a type of box
I often look for bas woofers that can fit for Sealed boxes.
One sealed box, does not need TUNING.
A badly tuned Bass Reflex will not work very well.
You tune with the Size + The length of bass reflex hole.
Sealed Box is more forgiving.
They will sound okay even ifyou have used 'the wrong size box'.
At least within some reson.
some woofers are more suited for Bass Reflex
other are specially made for Sealed Boxes
same, not all woofers are suitable for TL, transmission line boxes
it comes down to the thiele small electrical parameters
which woofer will suit best for a type of box
I often look for bas woofers that can fit for Sealed boxes.
One sealed box, does not need TUNING.
A badly tuned Bass Reflex will not work very well.
You tune with the Size + The length of bass reflex hole.
Sealed Box is more forgiving.
They will sound okay even ifyou have used 'the wrong size box'.
At least within some reson.
-u dont have to see it this way-
use
largest coil woofer for the size u use(the magnet must be vented)
(there's speakers that are to be used decompresseing by the coil or magnet-as you wish-and to decompress by the cabinet....or tweak them!!!!!!)
use as much glue as you need to really make sure of a sealled cabinet(assuming u'll have at least some 80w rms)
tweeter space behind it should be completelly sealled from the rest of air volume of the cabinet...
tricky part
choose a stuffing fiber that doesn't seem to colorate the sound when for example u put it next to your ear and the sound it's less affected(this is going to be hard so choose the best one for you from what u can find)
u can put some kind of rubber in the inside back of the cabinet
so now we're going to stuff up the cab and we're going to put the speaker pressurized,this means that when u close it and you push the cone you'll feel an opositte force(the air pressuring)and to the point that the speaker is going to take his time to return to point zero,this is the hard part cause you have to tune it experimenting until you take out all the bass frequencies linearly(almost)and the 2nd worst part it's that u have to tune both of the cabs(stereo)
There's actually high end mixing/mastering 2way speakers like this(probably more)i just saw ones on a regie,japanese and expensive-why we dont see them commercially?too much engineering probably=high cost
i've made this without calculations of course,and what you get have some lows-
-they become heavy to drive,so you need more power then before
-u might get crazy in the process of tunning the cabs
one thing that it's noticable beetwen vented and sealed is that the vented give's u more bass at low levels than sealled but if u like it loud(3/4 9/10 10)(assuming it plays clean-good power supply)the sealed one it's more accurate then the vented one and u can pass that point were u would stop understanding what goes on on the lower range with vented one
my pair i left it in Portugal cause they're too heavy ,and about sizes,let me tell you ,i used 8'' good woofers,suitable for subs,and the box was to a speaker of that dimmension on a vented design i just tweakd the box...but it took along time to get to zen
subwwofer???call me crazy but unless i used a 15'' with like 300wrms amp i wouldn't feel nothing besides more shaking in the house,on the sonic side that wouldn't had nothing different to the spectrum
of course the space were i would listen to them was treated with almost no reverbaration,very dry and little coloration so i wouldnt have so much of frequency cancellation and that kind of stuff
woofers were 150 nominal watts from an uk brand
the amp has a 500va transformer toshiba transistors(the ones before 2sc5200)rated 100wx2 continuous
the box was strong in a way that at maximum level u would barelly feel any vibration(honestlly)
but yeah with those speakers i would have my amp always running hot,but double bass,ambience sound,synths,(i'm a musician and i ear almost everything u can imagine)notice the cymbals on orquestras has they have an initial infra frequency(in some recordings it's noticable as they don't need rumble filtering)
pink floyd the wall--i'll tell that u can hear the guy playing acoustic guitar hitting his foot on the floor like we do when we're playing you know(well the room has to be silent and very dead)and u dont have to have them loud,althoug this is more in the mid bass ,mid , what let it come out is the controlled movement of the speaker
crazy????yap
after u push it all the way down with your hand,mine would take around 2 seconds to come up
the original ones?i thougt i wrecked them cause they got stucked but after some seconds(4 or 5) they went back to place
i know ,doesn't make since,it's just what it is and it's sound..
peace
use
largest coil woofer for the size u use(the magnet must be vented)
(there's speakers that are to be used decompresseing by the coil or magnet-as you wish-and to decompress by the cabinet....or tweak them!!!!!!)
use as much glue as you need to really make sure of a sealled cabinet(assuming u'll have at least some 80w rms)
tweeter space behind it should be completelly sealled from the rest of air volume of the cabinet...
tricky part
choose a stuffing fiber that doesn't seem to colorate the sound when for example u put it next to your ear and the sound it's less affected(this is going to be hard so choose the best one for you from what u can find)
u can put some kind of rubber in the inside back of the cabinet
so now we're going to stuff up the cab and we're going to put the speaker pressurized,this means that when u close it and you push the cone you'll feel an opositte force(the air pressuring)and to the point that the speaker is going to take his time to return to point zero,this is the hard part cause you have to tune it experimenting until you take out all the bass frequencies linearly(almost)and the 2nd worst part it's that u have to tune both of the cabs(stereo)
There's actually high end mixing/mastering 2way speakers like this(probably more)i just saw ones on a regie,japanese and expensive-why we dont see them commercially?too much engineering probably=high cost
i've made this without calculations of course,and what you get have some lows-
-they become heavy to drive,so you need more power then before
-u might get crazy in the process of tunning the cabs
one thing that it's noticable beetwen vented and sealed is that the vented give's u more bass at low levels than sealled but if u like it loud(3/4 9/10 10)(assuming it plays clean-good power supply)the sealed one it's more accurate then the vented one and u can pass that point were u would stop understanding what goes on on the lower range with vented one
my pair i left it in Portugal cause they're too heavy ,and about sizes,let me tell you ,i used 8'' good woofers,suitable for subs,and the box was to a speaker of that dimmension on a vented design i just tweakd the box...but it took along time to get to zen
subwwofer???call me crazy but unless i used a 15'' with like 300wrms amp i wouldn't feel nothing besides more shaking in the house,on the sonic side that wouldn't had nothing different to the spectrum
of course the space were i would listen to them was treated with almost no reverbaration,very dry and little coloration so i wouldnt have so much of frequency cancellation and that kind of stuff
woofers were 150 nominal watts from an uk brand
the amp has a 500va transformer toshiba transistors(the ones before 2sc5200)rated 100wx2 continuous
the box was strong in a way that at maximum level u would barelly feel any vibration(honestlly)
but yeah with those speakers i would have my amp always running hot,but double bass,ambience sound,synths,(i'm a musician and i ear almost everything u can imagine)notice the cymbals on orquestras has they have an initial infra frequency(in some recordings it's noticable as they don't need rumble filtering)
pink floyd the wall--i'll tell that u can hear the guy playing acoustic guitar hitting his foot on the floor like we do when we're playing you know(well the room has to be silent and very dead)and u dont have to have them loud,althoug this is more in the mid bass ,mid , what let it come out is the controlled movement of the speaker
crazy????yap
after u push it all the way down with your hand,mine would take around 2 seconds to come up
the original ones?i thougt i wrecked them cause they got stucked but after some seconds(4 or 5) they went back to place
i know ,doesn't make since,it's just what it is and it's sound..
peace
I read more after I replied. Many people mentioned your x-over problems, oops 
I believe you have a different woofer than me. I have what looks to be a Visaton AL 200 but with a copper colored cone made for Zetag.
Who is "he"? Sounds like Graham. He's a nice guy, but a bit of a fruity nut cake. Typical DIY audio enthusiast if you ask me
I believe you have a different woofer than me. I have what looks to be a Visaton AL 200 but with a copper colored cone made for Zetag.
Who is "he"? Sounds like Graham. He's a nice guy, but a bit of a fruity nut cake. Typical DIY audio enthusiast if you ask me
Yep that would be Graham. Yes I have the woofers out of the Zetag Hi G1s that are black in color. Graham raved about their quality. They are good, but i've still never been able to get the mains to sound the way I think they should. They sound good but not great when it comes to being detailed and clear in the high midrange. I don't think the tweeters are the problem, which I kinda thought was the case before with the focals I origionally used. Oh well.
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