Why a different mid-woof than you've used in your mains? That kindof defeats the purpose - you get different voicing.
The other question is, of course, how far off-axis is anyone going to be sitting?
I'm still trying to get gating and such right, but this is close enough to give a good idea of the inherent issues with an MTM on its side, off-axis. This is unsmoothed response. Dark red is 15 degrees. Green is 30 degrees. Pink is 45 degrees, blue 60. 15 degrees even up to ~20 degrees off-axis things are good. I think this is the same drivers as your mains I'm using here.
I would go TM or TMM, with the woofers side by side and touching, and the tweeter nestled in on top. Heck, if you have 17" of height to play with you could easily to a TMM 2.5.
Of course, I may have missed a bit in the middle posts, as I only skimmed them.
C
The other question is, of course, how far off-axis is anyone going to be sitting?
I'm still trying to get gating and such right, but this is close enough to give a good idea of the inherent issues with an MTM on its side, off-axis. This is unsmoothed response. Dark red is 15 degrees. Green is 30 degrees. Pink is 45 degrees, blue 60. 15 degrees even up to ~20 degrees off-axis things are good. I think this is the same drivers as your mains I'm using here.
I would go TM or TMM, with the woofers side by side and touching, and the tweeter nestled in on top. Heck, if you have 17" of height to play with you could easily to a TMM 2.5.
Of course, I may have missed a bit in the middle posts, as I only skimmed them.
C
In my opinion timbre matching is not as important as it is made out to be for the center channel. It would be a different story if all the front speakers and the center were involved in creating the same sound image but they are not. I think the goal for the center channel is to get as natural as possible of voice reproduction.
By the way Merlin I though I heard you mention that you were slightly disatisfied with your mains for female voice reproduction. Am I mistaken or was that another forum member. If this is the case you should not try to duplicate the mains speaker but build a center you like and then upgrade the mains or modify them as you are able.
I though somewere that you mentioned what your mains were but I don't remember where.
Hezz
By the way Merlin I though I heard you mention that you were slightly disatisfied with your mains for female voice reproduction. Am I mistaken or was that another forum member. If this is the case you should not try to duplicate the mains speaker but build a center you like and then upgrade the mains or modify them as you are able.
I though somewere that you mentioned what your mains were but I don't remember where.
Hezz
Vifa XG18's
here's the design
I just built them and I am quite happy with the results... So now they go back to the bottom of the list of things to come.
my list
1. Subwoofer - $500-$1000
2. Center channel - $200-$400
3. New, bigger TV - $500-$800
4. New DVD player - $200-$300.
So that's at least $1400 (more like $2000+) before I even think about new mains... that won't be for awhile. I am sure by then the upgrade bug will hit me again.
here's the design
I just built them and I am quite happy with the results... So now they go back to the bottom of the list of things to come.
my list
1. Subwoofer - $500-$1000
2. Center channel - $200-$400
3. New, bigger TV - $500-$800
4. New DVD player - $200-$300.
So that's at least $1400 (more like $2000+) before I even think about new mains... that won't be for awhile. I am sure by then the upgrade bug will hit me again.
Hezz said:
I wouldn't even say dissatisfied... They are still the best sounding speakers I have ever heard in my rather limited listening experience...
I have certainly never heard acoustic guitar or piano like this before... soo clear... It seems to make the piano stand out a little. My taste in music is changing in accordance to what my speakers like.
I also find they are improving slightly over time.
The (mainly female) voice reproduction could be better, which is probably a fairly common weakness with a 6.5"/7" 2-way. I coulda gone with a 5.5" but then I would have to cross the subs higher... a tradeoff... I hate when I can easily localize the sub.
I could easily live with a center that sounds like these... It's only a very minor thing. If its good enough for music it really should be good enough for HT CC.
It's so hard to decide how much I can invest and how to best invest my money when I have lots of time to wait for said money. I hope you guys like talking about all this stuff as much as I do and don't mind my considering of almost every possibility.
Merlin,
Vifa makes a fiberglass cone mid bass in the MG line which is shielded. Chances are the cone material is similar and would have a similar timbre as the XG18. They have both a 5.5 and a 7 inch. This would be a good substitute from a timbre matching point of view but lets look at the specs for crossover design frequency.
After looking at your mains design I feel that it is a reasonably good design. I think that the female voice issue is more likely to be a problem with your Techniques HT reciever than the speakers.
I you have a friend with a really high quality stereo set up you should take your mains over to there and hook them up to see how they really sound. The only problem will be that you will want a new stereo after that.
Hezz
Vifa makes a fiberglass cone mid bass in the MG line which is shielded. Chances are the cone material is similar and would have a similar timbre as the XG18. They have both a 5.5 and a 7 inch. This would be a good substitute from a timbre matching point of view but lets look at the specs for crossover design frequency.
After looking at your mains design I feel that it is a reasonably good design. I think that the female voice issue is more likely to be a problem with your Techniques HT reciever than the speakers.
I you have a friend with a really high quality stereo set up you should take your mains over to there and hook them up to see how they really sound. The only problem will be that you will want a new stereo after that.
Hezz
Merlin,
I have looked at the specs of the Vifa MG18SK09-08 7 inch mid bass and it would be a very good substitute for the XG18 as a center channel. The cone is a similar if not the same material. And it is a shielded speaker.
Timbre is generally more effected by material kind than anything else. There is no reason why you could not use this woofer with the Seas 27 TDFC/TV which is essentially the same tweeter with shielding.
There is also no reason why you could not set the crossover as high as 2500 Hz with a 12 db or higher crossover.
Why the designer of your mains chose 1700 Hz is because he was looking too much at the graphs and not thinking about sound and timbre. I don't care how good a tweeter is, if you cross it too low the timbre of certain sounds will not be exactly right.
The drivers of your mains are very good. It is possible to redesign the crossover in the future and get a slightly more smooth and integrated sound.
There is more to voicing a speaker than just looking at the graphs otherwise you could just say that any two speakers with a flat enough frequency response would all sound the same.
In my opinion any tweeter that moves into the fundamental tone range is treading on thin ground.
Sorry for getting on a soap box but I think that the above speakers will work for you and get about as good a timber match as you can get.
Also, I think that you will find that when you hook your speakers up to a higher end stereo system they will be better than you think.
I do not wish to disparage your HT reciever but a few years ago a few companies like JVC and Techniques and Pioneer who all used to make good sounding gear decided to make everything from OP amps and large scale integrated cheap IC's.
I went shopping for a modest priced HT reciever shortly after I had assembled a really good sounding stereo system out of Rotel, Adcom and Theta components. These pieces were all hand picked as the best sounding components in thier price categories. Then I built some Wilson Watt/Puppy clones and the result was magnificient.
Well when I went to audition 250 - 400 dollar HT recievers I could not believe my ears. I listened to everything that was available in a fairly large metropolitan area and I found that only three companies made modest costing HT recievers that I could even stand to listen to or be said to have a natural sound. This was about 4 years ago. I don't know if the scene has changed but I found only Onkyo, Yamaha and Harmon Kardon to me was listenable. Denon at 600 - 700 USD hade some things that were good and Adcom also in that price range. Bear in mind that all of these things were far below the sound quality of my main system but I expected that.
But what I did learn is that there are large differences in sound quality between certain companies and even between components within the same company and that sound quality is the lowest priority for large electronic stores as to them brands with a higher profit margin are more important to them. Ultimate Electronics dropped Onkyo their best brand for cost/performance for some reason and it was thier best sounding low priced gear. Go figure.
I tell you this just to illustrate that your front end makes a big difference and it is probably your front end that is the weakest link in the system at this point.
What will really be fun is when you have built all of your speakers as good as they can be and then if you upgrade your front end you really will be pleased.
Have fun.
Hezz
I have looked at the specs of the Vifa MG18SK09-08 7 inch mid bass and it would be a very good substitute for the XG18 as a center channel. The cone is a similar if not the same material. And it is a shielded speaker.
Timbre is generally more effected by material kind than anything else. There is no reason why you could not use this woofer with the Seas 27 TDFC/TV which is essentially the same tweeter with shielding.
There is also no reason why you could not set the crossover as high as 2500 Hz with a 12 db or higher crossover.
Why the designer of your mains chose 1700 Hz is because he was looking too much at the graphs and not thinking about sound and timbre. I don't care how good a tweeter is, if you cross it too low the timbre of certain sounds will not be exactly right.
The drivers of your mains are very good. It is possible to redesign the crossover in the future and get a slightly more smooth and integrated sound.
There is more to voicing a speaker than just looking at the graphs otherwise you could just say that any two speakers with a flat enough frequency response would all sound the same.
In my opinion any tweeter that moves into the fundamental tone range is treading on thin ground.
Sorry for getting on a soap box but I think that the above speakers will work for you and get about as good a timber match as you can get.
Also, I think that you will find that when you hook your speakers up to a higher end stereo system they will be better than you think.
I do not wish to disparage your HT reciever but a few years ago a few companies like JVC and Techniques and Pioneer who all used to make good sounding gear decided to make everything from OP amps and large scale integrated cheap IC's.
I went shopping for a modest priced HT reciever shortly after I had assembled a really good sounding stereo system out of Rotel, Adcom and Theta components. These pieces were all hand picked as the best sounding components in thier price categories. Then I built some Wilson Watt/Puppy clones and the result was magnificient.
Well when I went to audition 250 - 400 dollar HT recievers I could not believe my ears. I listened to everything that was available in a fairly large metropolitan area and I found that only three companies made modest costing HT recievers that I could even stand to listen to or be said to have a natural sound. This was about 4 years ago. I don't know if the scene has changed but I found only Onkyo, Yamaha and Harmon Kardon to me was listenable. Denon at 600 - 700 USD hade some things that were good and Adcom also in that price range. Bear in mind that all of these things were far below the sound quality of my main system but I expected that.
But what I did learn is that there are large differences in sound quality between certain companies and even between components within the same company and that sound quality is the lowest priority for large electronic stores as to them brands with a higher profit margin are more important to them. Ultimate Electronics dropped Onkyo their best brand for cost/performance for some reason and it was thier best sounding low priced gear. Go figure.
I tell you this just to illustrate that your front end makes a big difference and it is probably your front end that is the weakest link in the system at this point.
What will really be fun is when you have built all of your speakers as good as they can be and then if you upgrade your front end you really will be pleased.
Have fun.
Hezz
Having heard that very speaker, I can say that it can do female vocals *beautifully*.
Everything else I was going to say has been said in more depth by Hezz. Stick with a stiff cone.
Except that I don't agree that timbre matching isn't as important - I go so far as to say that it matters even with surrounds. On a film that really *uses* all the channels available to it. Most don't. YMMV.
C
Everything else I was going to say has been said in more depth by Hezz. Stick with a stiff cone.
Except that I don't agree that timbre matching isn't as important - I go so far as to say that it matters even with surrounds. On a film that really *uses* all the channels available to it. Most don't. YMMV.
C
Hi All,
I tried to read everything, but might have missed some sentences, so please forgive me if things I want to add are already said...
In the ideal case all 5 speakers are identical full range speakers (maybe even all including subs), but like most others in this post, I think good two fronts are most essential, then try to make all surrounds including center sound the same for Hz's that are directions dependent. Therefor e.g. I decided to go for two Rears using same tweeter and woofer (just one instead of two (Vifa Carat + Impuls)) as my Fronts do. My center is still on the design board, but will for sure contain the same units. Without a lot of thinking I went for two woofers like my fronts instead of one like rears.
The original horizontal design of Vifa for this center was build up by the tweeter on the same height (and also one bass-reflex-port on the same height), but in the new design the tweeter is somewhat higher having two smaller bass-reflex-ports. But I doubt if the filter was adapted for this physical change of phase??? See here a photo to better understand what I am talking about:
http://www.speakerenco.nl/speaker2.php?id=23
But back to the most important sentence in the middle of the describtion of my personal situation (sorry for that!!!):
I think good two fronts are most essential, then try to make all surrounds including center sound the same for Hz's that are directions dependent.
So if you cannot put the tweeter of you center speaker at the same height as your fronts (ear level when seated)
- Tilt the baffle!!!
- Why not consider to put it on the ceiling???
Oh, back to my situation, I am still a bit confused with the volume of the center speaker version of the Carat being significantly smaller than that of the front version!!!
Also, the design of the Front speaker contains a semi separated area for the lower woofer, this separation is also not present at the center version???
Can somebody tell me (preferably with arguments/experience) what I can do best:
- Increase the Volume to the level of the front speakers
- Implement a separation (that might impact left/right differences)
- Reconsider finetuning of filter with respect to position of tweeter and/or low frequency response (due to different box design/orientation)
Thanks for sharing all your stories so far,
Joep
I tried to read everything, but might have missed some sentences, so please forgive me if things I want to add are already said...
In the ideal case all 5 speakers are identical full range speakers (maybe even all including subs), but like most others in this post, I think good two fronts are most essential, then try to make all surrounds including center sound the same for Hz's that are directions dependent. Therefor e.g. I decided to go for two Rears using same tweeter and woofer (just one instead of two (Vifa Carat + Impuls)) as my Fronts do. My center is still on the design board, but will for sure contain the same units. Without a lot of thinking I went for two woofers like my fronts instead of one like rears.
The original horizontal design of Vifa for this center was build up by the tweeter on the same height (and also one bass-reflex-port on the same height), but in the new design the tweeter is somewhat higher having two smaller bass-reflex-ports. But I doubt if the filter was adapted for this physical change of phase??? See here a photo to better understand what I am talking about:
http://www.speakerenco.nl/speaker2.php?id=23
But back to the most important sentence in the middle of the describtion of my personal situation (sorry for that!!!):
I think good two fronts are most essential, then try to make all surrounds including center sound the same for Hz's that are directions dependent.
So if you cannot put the tweeter of you center speaker at the same height as your fronts (ear level when seated)
- Tilt the baffle!!!
- Why not consider to put it on the ceiling???
Oh, back to my situation, I am still a bit confused with the volume of the center speaker version of the Carat being significantly smaller than that of the front version!!!
Also, the design of the Front speaker contains a semi separated area for the lower woofer, this separation is also not present at the center version???
Can somebody tell me (preferably with arguments/experience) what I can do best:
- Increase the Volume to the level of the front speakers
- Implement a separation (that might impact left/right differences)
- Reconsider finetuning of filter with respect to position of tweeter and/or low frequency response (due to different box design/orientation)
Thanks for sharing all your stories so far,
Joep
Caratje,
Just a few responses to your questions.
Placing the tweeter higher up between the center of two mid bass drivers in the horizontal center channel configuration is one method of helping to alliviate part of the problems created by that design.
As to the different speaker volumes.
The center channel has less volume which makes it's bass response less good than the mains. This is done as a compromise because the center does not need as good of bass response. But unfortunately all things come at some expense because the transient response of the speaker is also not as good when the volume is lowered but with bass reflex designs this is less of a problem because the box is leaky.
Also, because the center channel speakers are ideally placed near the TV they usually have to be smaller in size by necessity. This does not however, improve certain aspects of the sound quality.
The separate chambers in the mains is probably because they are actually a 2.5 way design. Often only one speaker is the mid-bass and the upper one functions as a mid only. The seperation is to keep the lower frequency signals from modulating the midrange speaker which makes it more accurate.
It is also possible that the separate chambers is just an inexpensive way of bracing the speakers without having to make extra cuts. Since the total volume of the speaker cavity must be large enough to account for both speakers. So if you divide the speaker in half with a wall you are just giving each speaker it's own space and creating a brace at the same time.
Hezz
Just a few responses to your questions.
Placing the tweeter higher up between the center of two mid bass drivers in the horizontal center channel configuration is one method of helping to alliviate part of the problems created by that design.
As to the different speaker volumes.
The center channel has less volume which makes it's bass response less good than the mains. This is done as a compromise because the center does not need as good of bass response. But unfortunately all things come at some expense because the transient response of the speaker is also not as good when the volume is lowered but with bass reflex designs this is less of a problem because the box is leaky.
Also, because the center channel speakers are ideally placed near the TV they usually have to be smaller in size by necessity. This does not however, improve certain aspects of the sound quality.
The separate chambers in the mains is probably because they are actually a 2.5 way design. Often only one speaker is the mid-bass and the upper one functions as a mid only. The seperation is to keep the lower frequency signals from modulating the midrange speaker which makes it more accurate.
It is also possible that the separate chambers is just an inexpensive way of bracing the speakers without having to make extra cuts. Since the total volume of the speaker cavity must be large enough to account for both speakers. So if you divide the speaker in half with a wall you are just giving each speaker it's own space and creating a brace at the same time.
Hezz
One guy makes me consider new mains and the other tries to convince me I need a better receiver. Yeah the amp is a chip amp, I can see a huge IC through the vents at the top. I have an old Realistic amp that even sounds a little better (at least on the speakers I tried it on) . I was thinking about getting a high end pioneer (not elite but the highest standard line) but I've decided that's way down the list... I shouldn't be even considering it really.
About the Vifa MG18... I was eyeing already and you read my mind pretty much. I was just spacing out the hundreds of questions.
It's cheap, should be adequate although when you figure the cost of the whole thing by the time it's finished an extra little on the woofer doesn't make a whole lotta difference either.
I'm not sure on the TV stand either. It looks better but then I am stuck with the speaker at that exact spot and angle. If I make it separate I can try different positioning: i'll try above the TV,then I can put the TV on a temporary bench and angle the speaker below it. If I keep it below I can just make a small stand for it. This way if my listening room changes I can easily adapt the speaker if need be.
Are we going for form or function?
About the Vifa MG18... I was eyeing already and you read my mind pretty much. I was just spacing out the hundreds of questions.
It's cheap, should be adequate although when you figure the cost of the whole thing by the time it's finished an extra little on the woofer doesn't make a whole lotta difference either.
I'm not sure on the TV stand either. It looks better but then I am stuck with the speaker at that exact spot and angle. If I make it separate I can try different positioning: i'll try above the TV,then I can put the TV on a temporary bench and angle the speaker below it. If I keep it below I can just make a small stand for it. This way if my listening room changes I can easily adapt the speaker if need be.
Are we going for form or function?
Merlin,
In the end it's only you who knows what will work best for your home theater setup. I think the MG18 is as close as your going to get to your mains for a similar speaker. As far as the Tv stand cabinet goes that is purely a function thing for me as I am building a front projector. If you do not have these goals then a standard box may be the best for you. But bear in mind that there are not many placement options with a TV. Your either on top which means that unless your tv is large the speaker has to be quite small. Or underneath on a shelf. OF course you can place it on a stand in front of the TV but most people don't like the aesthetics of that.
I hope you don't think I am trying to change your priorities. I think It is fine that you are pursuing your speaker and sound transducers at the present time. I only wanted you to consider the source issue as it is bigger than you might think.
Keep us posted on your progress as it is interesting to see what you decide to do. One thing I would do is to look at some commercial designs which might work for you.
Here is a variation on the MTM which alleviates some of the problems that the MTM has in the horizontal orientation.
Hezz
In the end it's only you who knows what will work best for your home theater setup. I think the MG18 is as close as your going to get to your mains for a similar speaker. As far as the Tv stand cabinet goes that is purely a function thing for me as I am building a front projector. If you do not have these goals then a standard box may be the best for you. But bear in mind that there are not many placement options with a TV. Your either on top which means that unless your tv is large the speaker has to be quite small. Or underneath on a shelf. OF course you can place it on a stand in front of the TV but most people don't like the aesthetics of that.
I hope you don't think I am trying to change your priorities. I think It is fine that you are pursuing your speaker and sound transducers at the present time. I only wanted you to consider the source issue as it is bigger than you might think.
Keep us posted on your progress as it is interesting to see what you decide to do. One thing I would do is to look at some commercial designs which might work for you.
Here is a variation on the MTM which alleviates some of the problems that the MTM has in the horizontal orientation.
Hezz
Attachments
cjd said:Hey, I don't think you need new mains.
Why not add bucking magnets to the same Vifa woofers you're using in your mains?
C
You already know what I am just now figuring out... I'm gonna build a lotta speakers. I caught that bug that's been goin' around.
I guess that's 1 more thing to consider; DIY shielding. I don't know if I can recalculate the T/S params after i put a bucking magnet though.
Hi Hezz,
Thanks for trying to answer my questions, but of course I am not yet fully satisfied...
My fronts are indeed base on a 2.5 way principle with a semi separation between the tweeter+mid woofer and bass-woofer, but as far as I understand the center too (I think identical filter!!!) and that one is just one big open box??? But maybe this makes the full volume available for the bass-wafer larger!!!
So, I guess I kind of understand what has been done during the designing of the center speaker, having the fronts as 'holy' reference. At this moment I am sticking to that design and if I am not satisfied I might experiment with using the 2-way design (like my rears) or do measurement and reconsider the filter, but I expect it will be all fine!!!
Oh, CJD's remark on adding bucking magnets, I am not 100% sure if he is meaning the same, but shielding a woofer is for the largest part just putting a magnetic shield over the original magnet of the woofer. Basicly you can do this yourself on none-shielded woofers, but don't ask me for details on how to do this and how affective this will be???
Maybe my last question is a little of the original subject, but if you consider to put your center speaker above your television screen instead of below (height difference will be comparable and floor space is pretty important to me), how to do this best?
That means, is the wall beter than the ceiling (concrete ceiling, but very very hard!!!)
And do I still need spikes (between speaker and stage or fixate speaker box directly to wall/ceiling)
C U,
Joep
Thanks for trying to answer my questions, but of course I am not yet fully satisfied...
My fronts are indeed base on a 2.5 way principle with a semi separation between the tweeter+mid woofer and bass-woofer, but as far as I understand the center too (I think identical filter!!!) and that one is just one big open box??? But maybe this makes the full volume available for the bass-wafer larger!!!
So, I guess I kind of understand what has been done during the designing of the center speaker, having the fronts as 'holy' reference. At this moment I am sticking to that design and if I am not satisfied I might experiment with using the 2-way design (like my rears) or do measurement and reconsider the filter, but I expect it will be all fine!!!
Oh, CJD's remark on adding bucking magnets, I am not 100% sure if he is meaning the same, but shielding a woofer is for the largest part just putting a magnetic shield over the original magnet of the woofer. Basicly you can do this yourself on none-shielded woofers, but don't ask me for details on how to do this and how affective this will be???
Maybe my last question is a little of the original subject, but if you consider to put your center speaker above your television screen instead of below (height difference will be comparable and floor space is pretty important to me), how to do this best?
That means, is the wall beter than the ceiling (concrete ceiling, but very very hard!!!)
And do I still need spikes (between speaker and stage or fixate speaker box directly to wall/ceiling)
C U,
Joep
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