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post #1 of 60 Old 02-10-2014, 09:37 PM - Thread Starter
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I thought I had read that the SEOS-18 was going to have an option for a 1.4" CD but all I see is the 1" version. Does anybody know if this has ever came to fruition?

Thanks
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post #2 of 60 Old 02-11-2014, 05:07 AM
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I believe that you can order a 1.4" version, but, I think that all Erich has in stock at the moment are the 1" Seos-18's, which in my opinion, are kind of unnecessary as you won't be able to find a 1" compression driver that can be crossed over low enough to take advantage of the lower pattern control that the Seos-18 offers over the Seos-15, at least not enough to justify the price difference!
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post #3 of 60 Old 02-11-2014, 06:09 AM
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I disagree with Marty, will all due respect. When using waveguides, there is just like any other speaker designs, a list of tradeoffs. Bigger waveguides hold pattern lower as also avoid "funkiness" due to mouth diffraction a bit better for a given passband then their smaller brethen. This is why I opted to go with a SEOS18 over the smaller kin even though I was planning to cross around 1khz plus or minus a bit.

1.4" throats will start beaming sooner and most that use larger diaphragms will exhibit a breakup much lower in freq, enough to where I start to think you really need to use a tweeter. Many here will just ignore it, but if we are chasing the absolute highest level of performance, then you can see why I think its needed.

Dr. Geddes which is really the inspiration behind all the SEOS development in the first place has said many times that 1" CDs are the ideal for home use. GIven his set of criterion I see his point. He also had discussed that a 18" round OS would be the ideal mate for a 1" CD (again to my previous posts). I once argued this point on that super huge thread given a set of measurements comparing the 15" and 18" when planning to cross to a 15" but some disagreed. I think if you were to study those graphs hard you will see where we are coming from.

I am not at all against using bigger waveguides/CDs, in fact I am for them, I just think once you go with bigger CDs you except that you are now using a (super)tweeter and make the most of that new system tradeoffs.

I am using 2" CDs on Iwata 300hz and Beyma TPL-150H above them in my audio only system. For lower pattern control in a smallish room and higher sensitivity for tube amps.

I do agree with Marty that if you are going with 1.4" CDs, might as well go for the SEOS24 and then use a tweeter above, otherwise if sticking with SEOS18, I'd opt for 1" hardy CD like the B&C DE250/DIYSoundGroup version and cross ~850-1000hz. Those CDs can handle that in a home environment.

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post #4 of 60 Old 02-11-2014, 06:14 AM
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If you guys want a middle road between a SEOS24 and a 1" throat SEOS15 or 18 try the 18Sound XT1464. It has a narrower pattern but is a very nice horn at a good price. It is similar to the XR1464 that is in the Noesis, but better for home use IMO. My guess is that JTR used the XR horn because it is smaller and more durable for pro use.

I'd personally try one of the new beryllium Radian 3" voice coil drivers with it like the 6 or 7 series but you could use the larger 951 or a BMS coax. It depends how low you want to use the horn.

PNW has a build from a few years back that used this horn and some high end SEAS 10" woofers in an MTM. It is out there if you search for it. He used an 18Sound Al driver but I'd personally use the Be Radians instead.
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post #5 of 60 Old 02-11-2014, 07:19 AM
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Originally Posted by Martycool007 View Post

I believe that you can order a 1.4" version, but, I think that all Erich has in stock at the moment are the 1" Seos-18's, which in my opinion, are kind of unnecessary as you won't be able to find a 1" compression driver that can be crossed over low enough to take advantage of the lower pattern control that the Seos-18 offers over the Seos-15, at least not enough to justify the price difference!

On the contrary, the BA750 can be crossed over in the 600hz > 700hz region.

ryanC quote over on the DIY Sound Group forum.
"On the seos 18's here with crossover at 700hz I think it's a good idea to damp the WG's a little bit. I put two packages of rope caulk on each one and covered the whole thing with gorilla tape (on the back of the WG). Before I was getting some occasional shouty resonances with certain types of signals on the lower end of the WG's. After adding the (probably 5-6lbs per wg) rope caulk it's all gone. If they were heavy before...


Damn these speakers sound very good. So revealing dynamically. My test for dynamic transparency is to compare different peak stop limiters, on a lot of speakers they all sound kinda the same. Not on these bad boys, man each one is very distinct and more than a few dB of gain reduction they all sound kind a bad.


Just thought I would throw that out there."
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post #6 of 60 Old 02-11-2014, 12:40 PM
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For me, the SEOS-18™ (1" version) with BMS 4550 (1" CD) is still a possibility for surround speakers to complement the SEOS-24™ with BMS 4594ND coaxial LCR I am building. It's probably overkill though, hence i will most likely build the upgraded SEOS-15™ Sentinel v2.

The SEOS-18™ + 4550 (or the BA750) and a good 15" woofer seems like a very capable two-way IMO!

http://bmsspeakers.com/index.php?id=4550_specification

Building a HT with 7.2.4 layout and ◤SEOS-24◥ LCR.
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post #7 of 60 Old 02-11-2014, 05:45 PM
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Originally Posted by erwinfrombelgium View Post

For me, the SEOS-18™ (1" version) with BMS 4550 (1" CD) is still a possibility for surround speakers to complement the SEOS-24™ with BMS 4594ND coaxial LCR I am building. It's probably overkill though, hence i will most likely build the upgraded SEOS-15™ Sentinel v2.

The SEOS-18™ + 4550 (or the BA750) and a good 15" woofer seems like a very capable two-way IMO!

http://bmsspeakers.com/index.php?id=4550_specification

From what I have read, the BMS-4550 is very similar to the DNA-360, perhaps almost indistinguishable on a Seos-12, although perhaps slightly better on a Seos-15.

Wrt the Seos-18 with a 1" compression driver, I guess that I stand corrected. I assumed that the overall SQ would be limited by the compression driver, and would be unable to make full use of the lower pattern control of the larger Seos-18 compared to the Seos-15.

Now, wrt the BA-750, I must admit that I don't have much knowledge of this compression driver. Is it a 2" or 1.4"?
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post #8 of 60 Old 02-11-2014, 05:55 PM
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Originally Posted by Martycool007 View Post


Now, wrt the BA-750, I must admit that I don't have much knowledge of this compression driver. Is it a 2" or 1.4"?

1" throat, 2" voice coil.

http://www.diysoundgroup.com/compression-drivers/ba-750.html

http://www.diysoundgroup.com/forum/index.php?topic=31.0
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post #9 of 60 Old 02-11-2014, 06:21 PM
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Marty. You may have gotten that idea from me (albeit a little misunderstood). I told you in PM that the SEOS 18 is a bit of an awkward size because it has the ability to do better than most 1" CDs. I'm pretty sure I mentioned the BA-750. It's kind of like the SEOS 12 and 10" woofer design I did. The SEOS 12 is capable of mating to a 12" woofer or even a 15", but its not wasted on a 10" woofer. It's just not maxed out for lack of a better term. Like with a 15" woofer the SEOS 12 is maxed out and the XO point is not going to be flexible. It's sorta like the SEOS 18. The SEOS 15 can do everything the SEOS 18 can with the DNA-360, but the 18 will just do it more easily and cleaner. Personally I wouldn't want the added baffle width.

There was a really nicely detailed thread a few months ago of someone testing various CDs on the SEOS 18. He did a bang up job on the measurements. But I think he also discovered the CDs couldn't get way down to the lower limit of the waveguide without running out of steam.
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post #10 of 60 Old 02-11-2014, 06:39 PM
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I agree with Tux. There is nothing wrong the SEOS 18 but it is sort of in no man's land.
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post #11 of 60 Old 02-11-2014, 06:45 PM
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Well, when I took a look at the measurements originally (haven't seen the stuff Tux elluded to) there was the tell tale waste banding, which suggests pattern flip, a bit higher up than most people were crossing. This is one of the reasons why I prefered the SEOS 18 to cross <1khz.

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post #12 of 60 Old 02-11-2014, 06:46 PM - Thread Starter
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If the SEOS 18 has the option for a 1.4" cd then wouldn't that make better use of it?
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post #13 of 60 Old 02-11-2014, 07:04 PM
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Potentially yes. It is a tradeoff going to the larger throat.

Given the difference in price I'd personally go with the 18Sound XT1464 instead. Because of its narrower pattern it only needs to be 15" wide to hold pattern as low as 800hz and it will do a better job in the vertical.
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post #14 of 60 Old 02-11-2014, 10:31 PM - Thread Starter
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So for the sake of performance would it be worth it to step up to the SEOS 24 then?

I was hoping to keep the width down a little bit but if it is worth it then I will go for it after all I am more concerned with performance than looks.

I was thinking about mating it with a Radian 951be.

So now I just have to decide what woofers to match it with.
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post #15 of 60 Old 02-11-2014, 11:47 PM - Thread Starter
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Quote:
Originally Posted by AudioJosh View Post

I disagree with Marty, will all due respect. When using waveguides, there is just like any other speaker designs, a list of tradeoffs. Bigger waveguides hold pattern lower as also avoid "funkiness" due to mouth diffraction a bit better for a given passband then their smaller brethen. This is why I opted to go with a SEOS18 over the smaller kin even though I was planning to cross around 1khz plus or minus a bit.

1.4" throats will start beaming sooner and most that use larger diaphragms will exhibit a breakup much lower in freq, enough to where I start to think you really need to use a tweeter. Many here will just ignore it, but if we are chasing the absolute highest level of performance, then you can see why I think its needed.

Dr. Geddes which is really the inspiration behind all the SEOS development in the first place has said many times that 1" CDs are the ideal for home use. GIven his set of criterion I see his point. He also had discussed that a 18" round OS would be the ideal mate for a 1" CD (again to my previous posts). I once argued this point on that super huge thread given a set of measurements comparing the 15" and 18" when planning to cross to a 15" but some disagreed. I think if you were to study those graphs hard you will see where we are coming from.

I am not at all against using bigger waveguides/CDs, in fact I am for them, I just think once you go with bigger CDs you except that you are now using a (super)tweeter and make the most of that new system tradeoffs.

I am using 2" CDs on Iwata 300hz and Beyma TPL-150H above them in my audio only system. For lower pattern control in a smallish room and higher sensitivity for tube amps.

I do agree with Marty that if you are going with 1.4" CDs, might as well go for the SEOS24 and then use a tweeter above, otherwise if sticking with SEOS18, I'd opt for 1" hardy CD like the B&C DE250/DIYSoundGroup version and cross ~850-1000hz. Those CDs can handle that in a home environment.

I am new to all of this and this is the first time i have heard about using a tweeter along with a CD. What are the benefits of this?
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post #16 of 60 Old 02-12-2014, 03:59 AM
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Quote:
Originally Posted by ozziedog View Post

Quote:
Originally Posted by AudioJosh View Post

I disagree with Marty, will all due respect. When using waveguides, there is just like any other speaker designs, a list of tradeoffs. Bigger waveguides hold pattern lower as also avoid "funkiness" due to mouth diffraction a bit better for a given passband then their smaller brethen. This is why I opted to go with a SEOS18 over the smaller kin even though I was planning to cross around 1khz plus or minus a bit.

1.4" throats will start beaming sooner and most that use larger diaphragms will exhibit a breakup much lower in freq, enough to where I start to think you really need to use a tweeter. Many here will just ignore it, but if we are chasing the absolute highest level of performance, then you can see why I think its needed.

Dr. Geddes which is really the inspiration behind all the SEOS development in the first place has said many times that 1" CDs are the ideal for home use. GIven his set of criterion I see his point. He also had discussed that a 18" round OS would be the ideal mate for a 1" CD (again to my previous posts). I once argued this point on that super huge thread given a set of measurements comparing the 15" and 18" when planning to cross to a 15" but some disagreed. I think if you were to study those graphs hard you will see where we are coming from.

I am not at all against using bigger waveguides/CDs, in fact I am for them, I just think once you go with bigger CDs you except that you are now using a (super)tweeter and make the most of that new system tradeoffs.

I am using 2" CDs on Iwata 300hz and Beyma TPL-150H above them in my audio only system. For lower pattern control in a smallish room and higher sensitivity for tube amps.

I do agree with Marty that if you are going with 1.4" CDs, might as well go for the SEOS24 and then use a tweeter above, otherwise if sticking with SEOS18, I'd opt for 1" hardy CD like the B&C DE250/DIYSoundGroup version and cross ~850-1000hz. Those CDs can handle that in a home environment.

I am new to all of this and this is the first time i have heard about using a tweeter along with a CD. What are the benefits of this?
He obviously hasn't heard the BMS coax on a SEOS-24. Imo, an additional tweeter is not needed.

Mike
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post #17 of 60 Old 02-12-2014, 04:13 AM
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Originally Posted by coctostan View Post

Potentially yes. It is a tradeoff going to the larger throat.

Given the difference in price I'd personally go with the 18Sound XT1464 instead. Because of its narrower pattern it only needs to be 15" wide to hold pattern as low as 800hz and it will do a better job in the vertical.

So you like the XT1464 better than the Seos-18? Don't both have paternal control down to 800hz? What are the pro's and con's of going with the XT1464 over a Seos-18? (Besides the cheaper price and narrower form factor)

I believe that the XT1464 comes with a 1.4" opening, although I am not exactly sure, so can someone confirm this? Are there any other options available on the XT1464, perhaps a 1" option?
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post #18 of 60 Old 02-12-2014, 05:35 AM
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I am new to all of this and this is the first time i have heard about using a tweeter along with a CD. What are the benefits of this?

The CD needs to be one that can cover the low frequencies and preferably with a large enough horn to work down low. The midhorn would typically be used from about 400hz up to around 1200-1500hz. It is just another way to slice the pie.

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He obviously hasn't heard the BMS coax on a SEOS-24. Imo, an additional tweeter is not needed.

To counter that you obviously haven't heard the TPL-150H. The BMS coax has its downsides. So does Audiojosh's approach. Which is better is difficult to quantify.

Quote:
Originally Posted by Martycool007 View Post

So you like the XT1464 better than the Seos-18? Don't both have paternal control down to 800hz? What are the pro's and con's of going with the XT1464 over a Seos-18? (Besides the cheaper price and narrower form factor)

I believe that the XT1464 comes with a 1.4" opening, although I am not exactly sure, so can someone confirm this? Are there any other options available on the XT1464, perhaps a 1" option?

Well it is quite a bit cheaper and actually holds 90deg lower than a SEOS18. Personally I'd either stick to a SEOS15 with DNA360/4550/radianBe over a high end 15 or go to the Xt1464 or SEOS24. The performance difference between these will be very small and if well implemented damn near undetectable.

When moving to a 1.4" throat you are also typically moving to a larger diaphragm and voice coil than the 1" throats. This means they will usually perform better at lower frequencies. If I were pushing down to a 700-800hz crossover I'd probably go with one of the 1.4" throat 3" diaphragm Radian Be drivers which would make the XT1464 a logical choice. This could also be down with a 15" woofer and a cabinet slightly larger than 15".

These are all design choices. Every time you optimize in one direction you sacrifice in some other. Short of something like a Synergy design there isn't a way to get it "all".
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post #19 of 60 Old 02-12-2014, 06:35 AM - Thread Starter
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Originally Posted by coctostan View Post

The CD needs to be one that can cover the low frequencies and preferably with a large enough horn to work down low. The midhorn would typically be used from about 400hz up to around 1200-1500hz. It is just another way to slice the pie.
To counter that you obviously haven't heard the TPL-150H. The BMS coax has its downsides. So does Audiojosh's approach. Which is better is difficult to quantify.
Well it is quite a bit cheaper and actually holds 90deg lower than a SEOS18. Personally I'd either stick to a SEOS15 with DNA360/4550/radianBe over a high end 15 or go to the Xt1464 or SEOS24. The performance difference between these will be very small and if well implemented damn near undetectable.

When moving to a 1.4" throat you are also typically moving to a larger diaphragm and voice coil than the 1" throats. This means they will usually perform better at lower frequencies. If I were pushing down to a 700-800hz crossover I'd probably go with one of the 1.4" throat 3" diaphragm Radian Be drivers which would make the XT1464 a logical choice. This could also be down with a 15" woofer and a cabinet slightly larger than 15".

These are all design choices. Every time you optimize in one direction you sacrifice in some other. Short of something like a Synergy design there isn't a way to get it "all".

Since the XT1464 only has a frequency range up to 18khz, should a tweeter like the Beyma TPL-150H be used to help cover the top end?
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post #20 of 60 Old 02-12-2014, 06:48 AM
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The XT1464 has the possibility of response beyond there but you won't find a compression driver that size that can play beyond that cleanly.

I'll be blunt, you are swimming in depths that are a bit past your experience level here. Designing speakers well isn't as simple as picking fancy parts off a shelf. For instance, there would be no plausible way to use a a TPL-150H above an XT1464. At least not without introducing more problems than it solves. There are physics involved which make that a poor choice.

Beyond all of that, you still have to design a crossover whether it is passive or DSP. DSP may seem easy and it can be easy to get a mediocre result, but getting a results commensurate to the exceptional drivers being spec'd here is not a task for a novice. I'm not saying it is impossible, but there is quite a bit of learning required to make the right informed choices. If you want to cut your teeth on high end drivers that is fine, but understand that there is significant work to be done to make these uber-drivers worth their price.

Frankly, I'd rather have a simple kit of modest drivers that is well executed over a poorly designed speaker with world beating drivers.
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post #21 of 60 Old 02-12-2014, 06:53 AM - Thread Starter
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Originally Posted by coctostan View Post

The XT1464 has the possibility of response beyond there but you won't find a compression driver that size that can play beyond that cleanly.

I'll be blunt, you are swimming in depths that are a bit past your experience level here. Designing speakers well isn't as simple as picking fancy parts off a shelf. For instance, there would be no plausible way to use a a TPL-150H above an XT1464. At least not without introducing more problems than it solves. There are physics involved which make that a poor choice.

Beyond all of that, you still have to design a crossover whether it is passive or DSP. DSP may seem easy and it can be easy to get a mediocre result, but getting a results commensurate to the exceptional drivers being spec'd here is not a task for a novice. I'm not saying it is impossible, but there is quite a bit of learning required to make the right informed choices. If you want to cut your teeth on high end drivers that is fine, but understand that there is significant work to be done to make these uber-drivers worth their price.

Frankly, I'd rather have a simple kit of modest drivers that is well executed over a poorly designed speaker with world beating drivers.

Fair enough but that is in part what I am trying to do here, which is learn. In fairness the more I ask the more questions I have.
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post #22 of 60 Old 02-12-2014, 06:56 AM - Thread Starter
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While doing some searches I found this. It shows the SEOS 18 with a 1.4 or 1.5 inch throat and appears to be significantly taller than the regular SEOS 18. I wonder how this will effect its abilities?

http://gpoint-audio.com/wp-content/uploads/2013/03/seos18-2.jpg


http://gpoint-audio.com/wp-content/uploads/2013/03/seos18.jpg
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post #23 of 60 Old 02-12-2014, 07:00 AM
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Then you're asking the wrong questions. Instead of "driver A versus driver B" questions, you need to ask "how do speakers work?" Type questions.

My first full on speaker design with measurements and all the design was only a few years ago, but all the science, other builds, half ass designs, reading about designs, even taking courses, was a decade in the making. Yah, maybe I was slow and overdue, but the point is, its a slow process and not a simple forum explanation can do it. These are fun threads to banter about interesting ideas. But they won't get you to your ultimate goal.

FYI my first speaker design cost $150 for the pair, and I spent to much.
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post #24 of 60 Old 02-12-2014, 07:39 AM
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Then you're asking the wrong questions. Instead of "driver A versus driver B" questions, you need to ask "how do speakers work?" Type questions.

My first full on speaker design with measurements and all the design was only a few years ago, but all the science, other builds, half ass designs, reading about designs, even taking courses, was a decade in the making. Yah, maybe I was slow and overdue, but the point is, its a slow process and not a simple forum explanation can do it. These are fun threads to banter about interesting ideas. But they won't get you to your ultimate goal.

FYI my first speaker design cost $150 for the pair, and I spent to much.

+1 Tux

You can certainly start with top shelf drivers for your first design, but it is kind of a waste. I think it is also important that you have the desire to learn about speaker design not just wanting to build an uber speaker for less money than buying retail. ChopShop was less interested in actual design and basically commissioned the design to be done by an experienced designer (I don't know if MTG was compensated so commissioned might not be the right word, but he did the work).

Anybody can design a speaker...with enough learning and experience. Picking out drivers without understanding speaker design principles is putting the cart in front of the horse.
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post #25 of 60 Old 02-12-2014, 12:52 PM
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Originally Posted by ozziedog View Post

If the SEOS 18 has the option for a 1.4" cd then wouldn't that make better use of it?

There are only a few options for non-coaxial 1.4"CD. BMS has the 4554 (Ferro) with a recommended x-over of 1,000 Hz which is a point that can easily be covered by the SEOS-15™ too. The 4550 (Ferro 1" CD) seems the better choice with a recommended x-over of 800Hz.

The only other noc-coaxial 1,4" they have is the 4594ND-mid which obviously needs to be complemented by a separate tweeter. I guess it is no more than a coaxial 4594ND sans tweeter.

http://bmsspeakers.com/index.php?id=neodymium_compression_drivers
http://bmsspeakers.com/index.php?id=ferrite_compression_drivers

I decided that to make best use of the 4594ND coaxial 1.4", the SEOS-24™ was the better choice. As ChopShop's build proved. I chose two Beyma 18P80Nd as woofers for each LCR.

If you want to make best use of the non-coaxial BA750 or BMS4550, the SEOS-18™ is the 1" daddy... Perhaps (guessing here) it can even be complemented with one or two 18" woofers with x-over @ 700 Hz.

*BTW, you can order the 1,4" SEOS-18™ @ Auto-Tech in Poland if you insist.

Building a HT with 7.2.4 layout and ◤SEOS-24◥ LCR.
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post #26 of 60 Old 02-13-2014, 03:03 PM
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Originally Posted by coctostan View Post

Potentially yes. It is a tradeoff going to the larger throat.

Given the difference in price I'd personally go with the 18Sound XT1464 instead. Because of its narrower pattern it only needs to be 15" wide to hold pattern as low as 800hz and it will do a better job in the vertical.

For what it's worth, the SEOS-18 with the 1.4" throat looks more like the SEOS-24 than the original SEOS-18 with the 1" throat. It's 8.5" deep and 13" tall.


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Twelve 10" NHT subwoofer build.
Cloning of a NHT VR-3.
2 ACI 15" subwoofers.

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post #27 of 60 Old 02-13-2014, 03:14 PM - Thread Starter
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Originally Posted by Erich H View Post

For what it's worth, the SEOS-18 with the 1.4" throat looks more like the SEOS-24 than the original SEOS-18 with the 1" throat. It's 8.5" deep and 13" tall.

How is that going to effect it's performance?
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post #28 of 60 Old 02-13-2014, 05:00 PM
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To really know you would need to compare measurements. They will be more similar than different.
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post #29 of 60 Old 02-14-2014, 08:34 AM
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Originally Posted by Erich H View Post

For what it's worth, the SEOS-18 with the 1.4" throat looks more like the SEOS-24 than the original SEOS-18 with the 1" throat. It's 8.5" deep and 13" tall.

So can you confirm that the 1" Seos-18 is totally different that the 1.4" Seos-18? Why is that? Would the smaller 1" Seos-18 be any better than the normal Seos-15? I was all set on ordering a pair of 1" Seos-18's, but if they are different that the 1.4" Seos-18, then I may have to hold off until I can afford a better CD and a Seos-24, or just order a Seos-15. Problem is that if I go with the Seos-15, I will constantly be wondering how a Seos-18 would work, and thus, the upgrade big would likely start biting sooner rather than later. frown.gif
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post #30 of 60 Old 02-14-2014, 09:05 AM
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Marty, define your budget, performance requirements, and size constraints, and THEN design that system.
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