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bustaplz

Center channel MTM for Logitech Z-5500.

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I just ordered these components to build a custom center channel for my Logitech Z-5500 system that I run on my computer.

 

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=264-804

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=295-302 x2

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=260-144

 

In the future I will probably upgrade to a decent reciever and some different surround speakers. I replaced the fronts with a pair of Sony bookshelf speakers that I've had around for a while and liked the sound better so I'm going to upgrade the center channel. I'm probably going to build a new subwoofer box when I build this center channel to use a spare RE SR10D4 that I have.

 

This is a sketchup of the enclosure I have planned. It should be about .4 cubic feet tuned to 55hz after displacement. I used WINISD to do the calculations as I've never build a ported box for anything but subwoofers, but the response curve looked good for the woofers. It will act as a monitor stand also, that is why it is taller in the front, to fit the 5.25" woofers but keep my monitor at eye level. Anyone see any problems with my little plan? The center channel of the amp is rated at I think 69W@8ohms RMS.

 

CenterChannelMTM.jpg


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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I don't understand the fascination with an MTM center channel. It makes absolutely no sense to me.

 

One of advantages to running MTM setups is you reduce dispersion in the vertical plane, thereby reducing reflections caused by the ceiling- and more importantly- the floor ( floor bounce cancellation).

 

What happens when when you tip it on its side? Reduced dispersion in the HORIZONTAL plane. So what happens when you are not sitting directly on axis in the horizontal plane? uneven response and a reduction in volume.

 

But meh, do what you wish :) Better idea would be to do 2.5 way, with one of the woofers only playing midbass if you really need the extra output and reduction in distortion.


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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Well first of all, I'm not very educated on the subject and have very little experience.

 

Second, as far as I can understand, I'll be exactly on axis for the center channel. It will be probably 3-4 feet from me, at about chest height. Off axis response is not really a concern when the speakers are all pointed at a single chair, right?

 

I'm not trying to build something incredible, just experimenting and hoping to upgrade what I have now. And remember I'm going from 3" full range drivers to a two-way, three driver setup. I don't like the idea of full range drivers all that much so I wanted to try this kind of setup out.


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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I don't like the idea of full range drivers all that much so I wanted to try this kind of setup out.

 

You're certainly entitled to that opinion, but just curious how you heard them :)


qXvZLUF.png

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You're certainly entitled to that opinion, but just curious how you heard them :)

 

My opinion on full range drivers? Well, something about it sounds crowded to me. I have no scientific data or theory to back up my opinion, but switching from the stock front/left to the bookshelf speakers I had made quite a difference in mid-range. I use ProLogic quite a bit and true surround when available and notice that most of the important sound comes from the center channel so I decided to try the same with it. I looked at some retail center channels, most of them too expensive to buy and then started looking around at some HT projects and what was available cheap from PE. MTM seemed to be the most common alignment, and it doesn't seem to complicated for a first try. So there! If you have a better suggestion for the $60 or so this project will require, let's hear it!


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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Well first of all, I'm not very educated on the subject and have very little experience.

 

Second, as far as I can understand, I'll be exactly on axis for the center channel. It will be probably 3-4 feet from me, at about chest height. Off axis response is not really a concern when the speakers are all pointed at a single chair, right?

 

I'm not trying to build something incredible, just experimenting and hoping to upgrade what I have now. And remember I'm going from 3" full range drivers to a two-way, three driver setup. I don't like the idea of full range drivers all that much so I wanted to try this kind of setup out.

I understand, I was just venting mostly for home theater setups where the listeners are not on axis with the center :)

 

My opinion on full range drivers? Well, something about it sounds crowded to me. I have no scientific data or theory to back up my opinion, but switching from the stock front/left to the bookshelf speakers I had made quite a difference in mid-range. I use ProLogic quite a bit and true surround when available and notice that most of the important sound comes from the center channel so I decided to try the same with it. I looked at some retail center channels, most of them too expensive to buy and then started looking around at some HT projects and what was available cheap from PE. MTM seemed to be the most common alignment, and it doesn't seem to complicated for a first try. So there! If you have a better suggestion for the $60 or so this project will require, let's hear it!

Crowded? Really depends on the drivers and what frquency range you were running them in. I have played with several 3 inch drivers and found that playing below ~250hz gives the sound you describe. Congested and unnatrual. My suggestion? Run a bigger driver or a better drier such as the CSS FR125 or the Daton RS100. I have experience with the latter, and its quite nice above 150hz. For a center channel, you really don't need to go lower than that.

 

I am a strong advocate of using full range drivers for a center channel. Moving crossovers out of the vocal range really helps, especially with female voices. At the very least, go 2 way with a full range driver and a tweeter with a very high crossover (~10khz) clear from the vocal range.

 

$0.02


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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I have played with several 3 inch drivers and found that playing below ~250hz gives the sound you describe. Congested and unnatrual.

 

I've heard 3's that I've loved extending down past 150Hz, but you're talking about enclosures about as big as a medium-sized 'fridge :D


qXvZLUF.png

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I understand, I was just venting mostly for home theater setups where the listeners are not on axis with the center :)

 

 

Crowded? Really depends on the drivers and what frquency range you were running them in. I have played with several 3 inch drivers and found that playing below ~250hz gives the sound you describe. Congested and unnatrual. My suggestion? Run a bigger driver or a better drier such as the CSS FR125 or the Daton RS100. I have experience with the latter, and its quite nice above 150hz. For a center channel, you really don't need to go lower than that.

 

I am a strong advocate of using full range drivers for a center channel. Moving crossovers out of the vocal range really helps, especially with female voices. At the very least, go 2 way with a full range driver and a tweeter with a very high crossover (~10khz) clear from the vocal range.

 

$0.02

 

Makes sense, I guess I'll have to look into some full range drivers in the future. Maybe I'll try that as replacement for the surrounds(not that they really need replacing) if the center works out. I'll probably be building my own fronts if this project works out, I have a little sketch. They are angled slightly to sit against the edges of the center channel and point directly me. Would those 5.25" woofers be better suited serving in the fronts? What are reasonable alternatives to my center channel if I go that way?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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I've heard 3's that I've loved extending down past 150Hz, but you're talking about enclosures about as big as a medium-sized 'fridge :D

 

Well these 3" drivers are in plastic sealed enclosures probably about 6"x4"x4". They aren't terrible, probably better than most computer speakers I've heard, but that's not saying a whole lot. Compared to my $100 CDT component set, they sound like garbage. They also try very hard to play low, if I could adjust the crossover, maybe they would sound better, but I figure if the Z-5500 amp wants to send midbass signals, I'll use something that can handle those frequencies a bit better.


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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At the very least, go 2 way with a full range driver and a tweeter with a very high crossover (~10khz) clear from the vocal range.

 

What if I built my own 3-way crossover. Something like 700/7000 I think would be possible. And used one of the Tang Band drivers out of the Logitech speakers as full range, two woofers and the tweeter I bought. 4 drivers sounds like a lot to drive with 68w but I don't know. Should I ditch the woofers in the center channel altogether and just run a full range or two and tweeter?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

Share this post


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What if I built my own 3-way crossover. Something like 700/7000 I think would be possible. And used one of the Tang Band drivers out of the Logitech speakers as full range, two woofers and the tweeter I bought. 4 drivers sounds like a lot to drive with 68w but I don't know. Should I ditch the woofers in the center channel altogether and just run a full range or two and tweeter?
700 is a bit too high, I would aim for 300hz or even 200 to stay away from the vocal range. The upper crossover would be fine in that case.

 

The main thing to realize is that if you are going to go with a setup with a crossover point in the vocal range, then it needs to be implemented WELL. Three way sounds like way too much work for a center channel, but thats just my opinion.

 

Personally, I can tell the difference in the vocal range between full range drivers and well designed two way loudspeakers. A few of them come really close to perfection, but IMO none of them really have the magic of full range in the telephone band.

 

Anyway, thats all my opinion. If you want to do this right with two way, I would suggest going with an existing design that has been proven and thoroughly tested. One website in particular comes to mind. If you haven't been there, I suggest you do:

 

http://zaphaudio.com/

 

There are plenty of designs, ranging from stupid cheap to several hundred dollars. One in particular comes to mind:

 

http://zaphaudio.com/ZBM4.html

 

Just plop it on its side and away you go :veryhapp:


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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Thanks for the links, I like that design you posted. I don't know if I'll go by that yet, but what would be the best way to add in the mid-bass region if I'm using a full range driver?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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Thanks for the links, I like that design you posted. I don't know if I'll go by that yet, but what would be the best way to add in the mid-bass region if I'm using a full range driver?
Just designing a passive crossover and going "2-way" with a mid bass driver and a full range. Obviously with separate chambers in the enclosures.

 

Or just use a capable full range driver. Im telling you, the dayton RS100s have great bass, especially ported, and great extension all the way up to 20k. The 4ohm versions are best for ported alignments. The 8 ohm drivers have significantly different parameters, and are better suited for sealed alignments.

 

For 25 bucks, its hard to not try it :)


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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Just designing a passive crossover and going "2-way" with a mid bass driver and a full range. Obviously with separate chambers in the enclosures.

 

Or just use a capable full range driver. Im telling you, the dayton RS100s have great bass, especially ported, and great extension all the way up to 20k. The 4ohm versions are best for ported alignments. The 8 ohm drivers have significantly different parameters, and are better suited for sealed alignments.

 

For 25 bucks, its hard to not try it :)

 

Hadn't thought of that. Would a RS100 really be able to compete with a tweeter?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

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Hadn't thought of that. Would a RS100 really be able to compete with a tweeter?
If you notice there is a peak in the response after 10khz. I have found that this helps with the off-axis response up high. When I was running them in my car I had had no desire to add a tweeter. In fact, going to run two in the kicks per side, in ported enclosures as a 1.5 way with one of them playing midbass only.

 

However, I will say the Fostex FF85Ks that I just got are the most detailed 3 inch full range drivers I have ever owned. Mine are moded, so I don't know how they are in stock form. But I swear this things truly rival TWEETERS costing double or triple their price. Actually they are technically really stout tweeters, as the metal dustcap is attached directly to the voice coil. Wouldn't reccomend running these below 150-200hz, so a midbass driver will definitely work well for these. So it really depends on what you want, superb quality at a loss of bass, or great quality with great bass.

 

I have them running from 300hz on up crossed over to dual 15 inch drivers in open baffles:

 

0426091213.jpg

 

http://www.madisound.com/catalog/product_info.php?products_id=281


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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You guys have gotten me all kinds of confused. I'm going to build the original design since the parts get here tomorrow and see how it sounds. I'm really interested in that Fostex driver but I'm not sure I could properly utilize it. Maybe I'll order a couple and try them out as surround channels. Would one of those Fostex drivers and a 6.5" woofer work well in a front channel application? Another worry I have is that those are rated at 10w rms. Each channel on the Z-5500 is rated for a bit over 60w, how much of a problem would this be?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

Share this post


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You guys have gotten me all kinds of confused. I'm going to build the original design since the parts get here tomorrow and see how it sounds. I'm really interested in that Fostex driver but I'm not sure I could properly utilize it. Maybe I'll order a couple and try them out as surround channels. Would one of those Fostex drivers and a 6.5" woofer work well in a front channel application? Another worry I have is that those are rated at 10w rms. Each channel on the Z-5500 is rated for a bit over 60w, how much of a problem would this be?
I am powering my fostex with 50 watts per side. 10W is the mechanical limit, thermally they are taking it fine crossed over at 300hz

 

Sorry for confusing you so much. Just go ahead and build it and see how it sounds to YOU. If you don't like it, then you can experiment using the two woofers for midbass and a full range driver in the center.


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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I am powering my fostex with 50 watts per side. 10W is the mechanical limit, thermally they are taking it fine crossed over at 300hz

 

Sorry for confusing you so much. Just go ahead and build it and see how it sounds to YOU. If you don't like it, then you can experiment using the two woofers for midbass and a full range driver in the center.

 

I guess that makes sense, lower frequencies put more strain on the driver? I don't mind being confused ever so often. I've learned quite a bit from this thread. The idea of using a single driver to reproduce vocal range makes a lot of sense, what is the normal vocal range in HZ? I'm a singer/musician so I like to consider myself somewhat educated in the nature of sound but normally I would think of vocal range in terms of octaves on a music scale, never really thought about what that translates to frequency-wise.

 

Also, I've been looking at building crossovers, it seems like the lower the crossover point, the more expensive and bigger the crossover gets. Is that about right?


_______________________________________________

 

 

Pioneer DEH-P4800MP

Hifonics BXi608

2 RE Audio SR10 D4's in 2ft^3 tuned to 32.5hz

CDT Comps front, CDT Coaxials rear, MBQ DSC480

Seat-out Box:

Diamond D312D2 in 2ft^3 tuned to 34hz powered by a Diamond D3400.2

Other box:

2 Ascendant Audio Assasin 8's in 1.2ft^3 tuned to 40hz.

All in a red '04 Jeep Wrangler.

Share this post


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I guess that makes sense, lower frequencies put more strain on the driver? I don't mind being confused ever so often. I've learned quite a bit from this thread. The idea of using a single driver to reproduce vocal range makes a lot of sense, what is the normal vocal range in HZ? I'm a singer/musician so I like to consider myself somewhat educated in the nature of sound but normally I would think of vocal range in terms of octaves on a music scale, never really thought about what that translates to frequency-wise.

 

Also, I've been looking at building crossovers, it seems like the lower the crossover point, the more expensive and bigger the crossover gets. Is that about right?

Yup, it takes much more excursion to reach the same SPL at lower frequencies. Hence, when tweeters play music you can't see them move :cool:

 

As far as frequencies, just start at 20hz and for every doubling of frequency is a full octave. So for the auditory limits of humans (and therefore music), the entire frequency range of 20hz-20khz consists of 10 octaves of information.

 

Here is a great interactive graph of different instruments with respect to frequencies. Hover over the bands for more information. http://www.independentrecording.net/irn/resources/freqchart/main_display.htm

 

As you can see, the lower limit of a female vocalist is around 250hz. This is generally regarded as the lower limit of the vocal range, just because with most modern music even males don't go lower than that. Everything below that is generally harmonics.

 

The upper limit is debated, but the core is generally below 5khz, with sibilance going up to about 10khz. Hence, 10khz is a great place to cross over a tweeter to a full range driver for extra sparkle if it needs it, especially if its a larger (above 4 inch) full range. Its commonly reffered to as a super tweeter, because it plays so high, not because its super :)

 

As far as crossover points, yes the lower the crossover the point the more expensive the parts get. Thats why I suggest going with a quality full range driver that can dig low.


References: Lax916, AcidicDreams , Altima98 , mr Tibbs, Majette, giantgloworm, mattmcss, riogigalo, mysilver02alty, Woc47, Hintzyboy, oglejust, APitBullT, foreman, jhubbell, tmcilroy, pioneerpimp, Dre_ATL

 

Plus a ton more I never added, lol. If you are not on the list and you had a pleasant transaction with me, PM me!!!

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