JerMu-
The reason for the drop in the midrange is the great big L pad in front of the midrange -- I think it was 3 ohms in series and 4 ohms in parallel. The two mids in parallel would give you 93dB/2.83 V/1 M. (87+6). That L pad is about 6dB of attenuation.
My biggest comment would be that this design doesn't meet the 90dB criteria -- because of the limits of the woofers. I think it should come in at around 87 dB -- (because of the baffle step response). You will need a bigger box to get to 90dB.
JJ
The reason for the drop in the midrange is the great big L pad in front of the midrange -- I think it was 3 ohms in series and 4 ohms in parallel. The two mids in parallel would give you 93dB/2.83 V/1 M. (87+6). That L pad is about 6dB of attenuation.
My biggest comment would be that this design doesn't meet the 90dB criteria -- because of the limits of the woofers. I think it should come in at around 87 dB -- (because of the baffle step response). You will need a bigger box to get to 90dB.
JJ
Okay I see now; that is what I was thinking had to be going on (the Lpad)
However looking at the graphs (on PE) it seems that the woofers SHOULD be able to atleast hold their own at 89db...one driver hangs between 85-86db; shouldn't 2 hang out at or just below 90db (x2 = +6db)...what am I not seeing?
I was thinking of finding a set of woofers that would get me to the 90db mark (if the ones being used won't), and, depending on you guys' thoughts, maybe pick another tweeter however John Holtz seems to really like the sound from that tweeter and it can meet the 90db mark easily, but I'm open to options.
However looking at the graphs (on PE) it seems that the woofers SHOULD be able to atleast hold their own at 89db...one driver hangs between 85-86db; shouldn't 2 hang out at or just below 90db (x2 = +6db)...what am I not seeing?
I was thinking of finding a set of woofers that would get me to the 90db mark (if the ones being used won't), and, depending on you guys' thoughts, maybe pick another tweeter however John Holtz seems to really like the sound from that tweeter and it can meet the 90db mark easily, but I'm open to options.
Your upper frquencies radiate mostly into a 2pi (halfspace) environment -- most of the sound radiates forward of the baffle. At some point (from the Northcreek website -- " at the wavelength twice the baffle width") the sound begins radiating into 4pi (fullspace) environment. You then lose 6dB of response, so your two RS225-8's in parallel that would be about 93 db into a 2pi environment, are back down (theoretically) to 87 dB. I have read that the Baffle Step Response is often more realistically 4.5 to 5 dB due to room effects and the proximity to the wall behind the speaker. I've never tried to closely measure it though.
I built my last pair of speakers with that 3" 87dB TI midrange. I tried to use two RS150-8's as the woofers, which are listed at 88dB/2.83v/m. But in truth, I think they were more like 86dB. I didn't have enough bass, and I didn't want a resistor in front of the midrange, so I ended up with 4 RS150-4's in series-parallel, which gets you +3dB with the same impedence.
This is the reason I had asked Tinitus about the published sensitivity for the Aurum Cantus drivers -- they are listed at 90dB/2.83v/m. I was considering them for the 7" woofers, to get a 90dB TMWW speaker.
JJ
Would the effect of changing the "Statement's" alignment from WMTMW to MTMWW be bad?
Also if I wanted to "tweak" the box shape and dimensions slightly would that be bad? I would of course maintain the internal volumes needed, I was just thinking of playing with the proportions a bit.
What do you guys think of these:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-446
http://www.madisound.com/catalog/product_info.php?cPath=45_229_246&products_id=286
http://www.madisound.com/catalog/product_info.php?cPath=45_229_250&products_id=790
Also if I wanted to "tweak" the box shape and dimensions slightly would that be bad? I would of course maintain the internal volumes needed, I was just thinking of playing with the proportions a bit.
What do you guys think of these:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=297-446
http://www.madisound.com/catalog/product_info.php?cPath=45_229_246&products_id=286
http://www.madisound.com/catalog/product_info.php?cPath=45_229_250&products_id=790
JJ is right that it is very difficult to calculate sensitivity on a speaker, and you will never know until it is finished
THIS IS NOT A SUGGESTION, but I wonder how it would work with a 2.5way WWWT or even WWWTW, all 4" TB ti and a maybe a Peerless XT19 tweet(because I have a pair), could be a neat slick little standmount speaker
Those Hivi M-series woofers will probably work fine
THIS IS NOT A SUGGESTION, but I wonder how it would work with a 2.5way WWWT or even WWWTW, all 4" TB ti and a maybe a Peerless XT19 tweet(because I have a pair), could be a neat slick little standmount speaker
Those Hivi M-series woofers will probably work fine
The Statements do have a bit of woodworking involved. The crossover assumes that the Tang Band is open back. So a pre made cabinet may not work. The open back adds 4db to the mid due to reflection off the back wall.
I think the mini's are bigger than most PE boxes.
Changing the front dimensions of the cabinet would effect baffle step compensation. But MTMWW should work OK if I remember what Loudspeaker Design Cookbook said about that.
I think the mini's are bigger than most PE boxes.
Changing the front dimensions of the cabinet would effect baffle step compensation. But MTMWW should work OK if I remember what Loudspeaker Design Cookbook said about that.
Loudspeaker Design Cookbook says that each shape yeilds a varying effect on the sensitivity of the finished speaker (is this the baffle step compensation you guys are talking about?)...I think circles are the best with perfect squares being the worst.
My idea for the box remains mostly rectilinar with slight slopes on the sides just to set it apart from the typical shoe box design - thus why I was asking about changing to a MTMWW because if I slope the side I loose a bit on the top and I'm not sure if the woofer will fit, and I don't want to go taller.
Woodworking is not a problem and I welcome the challenge....(I probably will regret saying that but oh well...)
Woot! I have somewhat of a game plan established...
About the XO...granted I need to read Loudspeaker Design Cookbook about 50 million more times, but since you guys have said it is hard to calculate final sensitivity how do you know the attenuation adjustments that need to be made in order to achieve a certian sensitivity. And I'm fine with and 89db system or a 91 db system, I just wonder the process involved to flatten the system. Is that adjustments that are made after things are together and you then measure the sound levels?
My idea for the box remains mostly rectilinar with slight slopes on the sides just to set it apart from the typical shoe box design - thus why I was asking about changing to a MTMWW because if I slope the side I loose a bit on the top and I'm not sure if the woofer will fit, and I don't want to go taller.
Woodworking is not a problem and I welcome the challenge....(I probably will regret saying that but oh well...)
Woot! I have somewhat of a game plan established...
About the XO...granted I need to read Loudspeaker Design Cookbook about 50 million more times, but since you guys have said it is hard to calculate final sensitivity how do you know the attenuation adjustments that need to be made in order to achieve a certian sensitivity. And I'm fine with and 89db system or a 91 db system, I just wonder the process involved to flatten the system. Is that adjustments that are made after things are together and you then measure the sound levels?
Look at the "6 dB response step" here for an explanation of the baffle step compensation.
Where was that in the LDC (and which edition do you have?)? I can take a look, but the shape factor thing doesn't sound familiar.
I don't think the HiVi driver will work -- it is listed at 86 dB/2.83V/1 M -- even worse than the Dayton RS drivers. You will end up with roughly an 86dB/2.83 V/1 M speaker. (unless you want to mount these right on the wall.) I would stick with the Dayton drivers over the HiVi.
I don't think doing MTMWW would cause any problems. If it did, it would be very specific to the crossover used, and I think you are looking at redesigning the Xover anyway.
That is the only way I have found to do it. But then, that applies to crossover design in general. I use Crossover 3 Pro to design my crossovers. Then I listen, and tweek, and take measurements. Then, I compare what I have measured to what the design program is telling me.
JJ
Let's talk tweeters:
Just to be on the safe side, it would be good to get one that can be crossed over at 2000hz, if necessary. The type of "failure" Tinitus mentioned would come if you really needed a 2K crossover point, but your tweeter couldn't be crossed over below 3K.
I would shoot for a 3K crossover point to start with when designing the XO.
1) the ribbon tweeter from the statement project -- I have no experience with ribbon tweeters, and I don't think Xover 3 pro can model them. I would like to try them, but I can't offer any opinion.
2) Vifa D25AG-35-1 -- good tweeter, although I think I once read that a batch of these came out sizzly. I have a pair, and they sound great. Not sure if these will be discontinued.
3)FT17H -- too high crossover frequency.
4)Seas 27TBC/G -- no experience with this, but I really like SEAS. All the spec's look OK to meet your needs.
5) Seas 22 TAF/G -- I would really like to try this tweeter out. The 2500 hz required x-over freq. might be a problem if the midranges wanted to be crossed over low. (they shouldn't, but I haven't built with them, so that is just a guess)
Later I can list some I have used and like.
JJ
Just to be on the safe side, it would be good to get one that can be crossed over at 2000hz, if necessary. The type of "failure" Tinitus mentioned would come if you really needed a 2K crossover point, but your tweeter couldn't be crossed over below 3K.
I would shoot for a 3K crossover point to start with when designing the XO.
1) the ribbon tweeter from the statement project -- I have no experience with ribbon tweeters, and I don't think Xover 3 pro can model them. I would like to try them, but I can't offer any opinion.
2) Vifa D25AG-35-1 -- good tweeter, although I think I once read that a batch of these came out sizzly. I have a pair, and they sound great. Not sure if these will be discontinued.
3)FT17H -- too high crossover frequency.
4)Seas 27TBC/G -- no experience with this, but I really like SEAS. All the spec's look OK to meet your needs.
5) Seas 22 TAF/G -- I would really like to try this tweeter out. The 2500 hz required x-over freq. might be a problem if the midranges wanted to be crossed over low. (they shouldn't, but I haven't built with them, so that is just a guess)
Later I can list some I have used and like.
JJ
It looks to me like the HiVi has a much higher db level on the graph they give, I thought this would infact help me get closer to the 90db range than the Dayton...after double checking the stats I do see where they call the spl at 86db, but the graph shows otherwise...what do you guys think?
Again...2.5way WWWT, ALL TB 4"ti, low woofers wired in series, tweeter XT19, high xo point with 6db filters...all the way round, mains, back and center...stereo subs, maybe double 10" AC, crossed active around 100hz, preferably 12db...will it work? hell, I dont know
Just ignore it, please
I dont think I will waste time in redesigning the "Statement", the idea might be ok though
Just ignore it, please
I dont think I will waste time in redesigning the "Statement", the idea might be ok though
I think I read somewhere once that the response shown on graphs for the HiVi drivers were a bit higher than actual. Bass driver sensitivity is an issue that I struggled with a lot, looking at many, many, different 6 3/4" drivers to find ones that have relatively high (90 dB) sensitivity.
JJ
Tinitus--I tried modelling 4 4" drivers using crossover 3 pro as a 2.5 way. (the file was for an Infinity CMMD driver made by Vifa -- I have a stash of them). The best I got giving it a quick try with a simple crossover was about -2dB at 100Hz (with BSC). Didn't model the TB TI 4" drivers -- I plan on loading up the manufacturer specs and giving it a try though. I think it would work.
JJ, sounds good, will be interesting
The reason I "suggested" 3 drivers was to either avoid low impedance, or the possibility with either paralel or serial connection of the low 0.5way woofer to influence BSC
But if higher sensitivity is the ultimate goal there is no way around 4 drivers, as you suggest...honestly I am not keen on double mids, although it may be nice to have the better power handling...maybe they could be connected in series
The reason I "suggested" 3 drivers was to either avoid low impedance, or the possibility with either paralel or serial connection of the low 0.5way woofer to influence BSC
But if higher sensitivity is the ultimate goal there is no way around 4 drivers, as you suggest...honestly I am not keen on double mids, although it may be nice to have the better power handling...maybe they could be connected in series
So I should assume that the lower 86db is correct and the graph isn't. I guess it is good practice in any case to plan for the worst...
Is this converstation about 4 TB's in response to the earlier posts about WMMTMMW or is this a side topic that is developing. Not that I care I am just wondering if this is an idea TiniTus is coming up with for something he wants to do or if I should be trying to apply it to what I am doing. I ask because he's prefaced one of his posts with "This is not a suggestion" so I just took it as a side note to conisider, and not really something to apply.
Do you guys have any suggestion on woofers that might get me to the 90db mark that are worthy of noting?
In line with the thread just trying to figure out how to design a complete and coherent surround setup with the 4"TB ti...just an idea, we are trying to help you not to get into too much trouble...if you dont like it, just ignore it...and no, I am not a surround guy, so maybe I shouldnt be here at all
Be aware that too much bass is almost the worst that can happen, not much you could do about that
Also be sure that your surround amp can handle a low impedance
Be aware that too much bass is almost the worst that can happen, not much you could do about that
Also be sure that your surround amp can handle a low impedance
No No I do appreciate the idea, and you are trying to follow what I want to do. I just wanted to clarify if you were heading down another path with the WWWT idea because you said "this is not a suggestion" I just got confused.
Even though you might not be a surround guy, your knowledge is welcome. You've been throwing out plenty of good stuff....dont' leave!
Now if I do achieve too much bass is that not something that can be worked out in the XO?
Right now my amp is a 5.1 JVC reciever which I intend to upgrade so I can consider 7.1 in the near future and just because it is soooooooo old. My .1 sub is an Atlas 12 by ascendant adio powered by a PE 250 watt amp, and is something that I am going to consider upgrading too once I hear the system and how the sub matches with it. Right now it is a bit on the puny side if you ask me, but we'll see once everything is said and done. I'm definetly doing the step by step process that you suggested...first and foremost is my mains, then the center, and then the surrounds, and once that is all in place I'll evaluate how my sub is with the rest of the system and decide at that time what I need to do.
I pretty much think the "statement" is going to be what I build, BUT I would like to "tweak" it slightly to achieve the 90db, and play with the proportions a bit (if possible) to try to make it less bulky...from what I see with the TB ti's 90db is possible with the two being used in the original design, and I can either use the ribbon tweeter John Holtz used or pick a new one but the 90db should also be doable on the tweeter too. I need a set of woofers that will do the 90db and then I think I'm good to imbark on the "statement" project where I will need to edit the XO a bit for the new drivers being used, and to flatten everything at 90ish-db, but I haven't even begun to think about what all needs to be done in that regard - which might be a noob mistake on my part.
Even though you might not be a surround guy, your knowledge is welcome. You've been throwing out plenty of good stuff....dont' leave!
Now if I do achieve too much bass is that not something that can be worked out in the XO?
Right now my amp is a 5.1 JVC reciever which I intend to upgrade so I can consider 7.1 in the near future and just because it is soooooooo old. My .1 sub is an Atlas 12 by ascendant adio powered by a PE 250 watt amp, and is something that I am going to consider upgrading too once I hear the system and how the sub matches with it. Right now it is a bit on the puny side if you ask me, but we'll see once everything is said and done. I'm definetly doing the step by step process that you suggested...first and foremost is my mains, then the center, and then the surrounds, and once that is all in place I'll evaluate how my sub is with the rest of the system and decide at that time what I need to do.
I pretty much think the "statement" is going to be what I build, BUT I would like to "tweak" it slightly to achieve the 90db, and play with the proportions a bit (if possible) to try to make it less bulky...from what I see with the TB ti's 90db is possible with the two being used in the original design, and I can either use the ribbon tweeter John Holtz used or pick a new one but the 90db should also be doable on the tweeter too. I need a set of woofers that will do the 90db and then I think I'm good to imbark on the "statement" project where I will need to edit the XO a bit for the new drivers being used, and to flatten everything at 90ish-db, but I haven't even begun to think about what all needs to be done in that regard - which might be a noob mistake on my part.
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