About a year ago I built up a pair of hybrid OB speakers using a RS270 10 inch woofer in a sealed box, a Peerless 830883 mid and SB29 tweeter 2nd order 300 and 2200. They sound good but I am always willing to improve on it.
If you were in my position to pick out the weakest link (driver), which if any do you think is a candidate and why?
Thanks for your advice.
If you were in my position to pick out the weakest link (driver), which if any do you think is a candidate and why?
Thanks for your advice.
Hi,
I'll guarantee the execution is more of a problem
than the drivers and swapping drivers won't fix it.
Vented might improve matters but is not the real
issue, and the large driver Vas suggests sealed.
The real issue in likely the bass to mid x/o, proper
EQing of the baffle hump, proper mid level and
then proper mid to treble integration and level.
Saying you just used 2nd order x/o's doesn't
begin to cover the issues. Done properly you
would know any new drivers would need
some x/o modifications and redesign.
OB mids are very tricky if you cannot measure.
For sure IMO you'll need a series (parallel LCR)
trap on the mid to start getting anywhere.
(e.g. https://sites.google.com/site/undefinition/diy-sunflowers)
Its all in the x/o design, and once you've done that
properly thoughts will not wander to different drivers.
I cannot see any real point in changing any of your drivers,
except for the fact the bass unit is ~ the same sensitivity
as the mid, which will involve attenuating the mid quite
a bit. Another option is going active bass to mid and
mid EQ with a passive x/o mid to treble.
100W on the bass would be quite happy with a nice
25W (Death of Zen - class A) amplifier for mid/treble.
rgds, sreten.
I'll guarantee the execution is more of a problem
than the drivers and swapping drivers won't fix it.
Vented might improve matters but is not the real
issue, and the large driver Vas suggests sealed.
The real issue in likely the bass to mid x/o, proper
EQing of the baffle hump, proper mid level and
then proper mid to treble integration and level.
Saying you just used 2nd order x/o's doesn't
begin to cover the issues. Done properly you
would know any new drivers would need
some x/o modifications and redesign.
OB mids are very tricky if you cannot measure.
For sure IMO you'll need a series (parallel LCR)
trap on the mid to start getting anywhere.
(e.g. https://sites.google.com/site/undefinition/diy-sunflowers)
Its all in the x/o design, and once you've done that
properly thoughts will not wander to different drivers.
I cannot see any real point in changing any of your drivers,
except for the fact the bass unit is ~ the same sensitivity
as the mid, which will involve attenuating the mid quite
a bit. Another option is going active bass to mid and
mid EQ with a passive x/o mid to treble.
100W on the bass would be quite happy with a nice
25W (Death of Zen - class A) amplifier for mid/treble.
rgds, sreten.
OK, So I agree with the XO discussion. I wanted to leave that out of the equation because Dumptruck assisted me with in a lengthy design period (and measurements) and I am confident that with his experience and assistance it came out as good as it could based on our exchanges. Much thanks to him for all his help.
I did not want to bias your recommendations by stating what I believed to be the area to start with. And YES if I touch ANYTHING at all the whole design must be reviewed again!! I am on board with you on that!!
The mid is attenuated but I can tell you that it sounds very good.
If i were me
I think it is the bass driver that I would change and revisit the XO. But what Bass driver to use? I want to stay sealed in approx 1.6 cu ft.
I did not want to bias your recommendations by stating what I believed to be the area to start with. And YES if I touch ANYTHING at all the whole design must be reviewed again!! I am on board with you on that!!
The mid is attenuated but I can tell you that it sounds very good.
If i were me
I think it is the bass driver that I would change and revisit the XO. But what Bass driver to use? I want to stay sealed in approx 1.6 cu ft.Hi, I'm that dumptruck, and I helped with this design via email during a time when I didn't have anything to work on, going back and forth with jimbones taking measurements. I had nothing to do with the speaker design outside of the xover, and I've never heard it.
Anyway, jimbones was just getting started with taking measurements, and the room was smaller than you'd want to get measurements of this driver layout, so I was never very confident in the design and probably drove jimbones nuts with requests to try to take reverse null measurements in various ways, but I did at least attempt to get all the basics right, and he declared it finished. I would not be the least bit offended if you guys want to try to dig into some more measurements and see if we screwed anything up. Just don't go into it assuming it's a random mess created by online calculators or something.
Anyway, jimbones was just getting started with taking measurements, and the room was smaller than you'd want to get measurements of this driver layout, so I was never very confident in the design and probably drove jimbones nuts with requests to try to take reverse null measurements in various ways, but I did at least attempt to get all the basics right, and he declared it finished. I would not be the least bit offended if you guys want to try to dig into some more measurements and see if we screwed anything up. Just don't go into it assuming it's a random mess created by online calculators or something.
Dumptruck,
I think the chance of me getting involved into more measurements
would be like the chance of winning a lottery jackpot. It should also
be noted that newbies often strive to build over and over again and
it does not necessarily mean something was wrong with the speaker
project. It is only natural until everything settles down and enough
money is spent.
I think the chance of me getting involved into more measurements
would be like the chance of winning a lottery jackpot. It should also
be noted that newbies often strive to build over and over again and
it does not necessarily mean something was wrong with the speaker
project. It is only natural until everything settles down and enough
money is spent
.
If you already had the sub, then I don't see why need for RS270.
You could have let the Peerless play all the way down to 50 Hz
and cross to the sub there.
Guys,
I confess I am a newbie. I come here because I respect the opinions of people that have "been there, done that". I know I sound defensive but I don't come to fight or profess to know more than the next guy. I am appreciative of those that provide constructive criticisim. The only reason that I declared the project "finished" was (1) I felt guilty that DT was spending as much time as he did and I am grateful for his help and he knows it and (2) I wanted to get some listening time on the speakers to make some observations then work on them some more. I have made investments in Omnimic and have gathered all the recommended software tools (SPL Trace/PCD etc) and learned how to use them. However we all know working solely by email exchange is challenging.
Dumptruck hit the nail on the head. Without me explaining the whole story in every gory detail I am only asking if there was anything obviously wrong with the driver selection. For example, In an earlier build I was using a Dynaudio 17W75 and literally everyone said that that driver was a poor choice. (I only used it because I had it lying around and didn't cost me $). Thank you for your understanding.
I confess I am a newbie. I come here because I respect the opinions of people that have "been there, done that". I know I sound defensive but I don't come to fight or profess to know more than the next guy. I am appreciative of those that provide constructive criticisim. The only reason that I declared the project "finished" was (1) I felt guilty that DT was spending as much time as he did and I am grateful for his help and he knows it and (2) I wanted to get some listening time on the speakers to make some observations then work on them some more. I have made investments in Omnimic and have gathered all the recommended software tools (SPL Trace/PCD etc) and learned how to use them. However we all know working solely by email exchange is challenging.
Dumptruck hit the nail on the head. Without me explaining the whole story in every gory detail I am only asking if there was anything obviously wrong with the driver selection. For example, In an earlier build I was using a Dynaudio 17W75 and literally everyone said that that driver was a poor choice. (I only used it because I had it lying around and didn't cost me $). Thank you for your understanding.
Jim,
I don't think you made any mistake with driver choice of yours and
I feel obligated to say people posting here making suggestions are
only humans and thereby capable of making mistakes. Regarding your
17W75, I guess I was the "only" one speaking in favor of this driver
IIRC. It has something to do with philosophy of thinking and I tend not
to believe everything written in books.
I don't think you made any mistake with driver choice of yours and
I feel obligated to say people posting here making suggestions are
only humans and thereby capable of making mistakes. Regarding your
17W75, I guess I was the "only" one speaking in favor of this driver
IIRC. It has something to do with philosophy of thinking and I tend not
to believe everything written in books.
Thanks Lojzek.
I like the dynaudio myself and it sounded ok. However when another DIY'er (Mdcod) before Dumptruck assisted me with the the original design I ran the data through pcd we did have difficulty getting it to play nice at the upper end with the tweeter. I was advised by Blair that he used the peerless OB with excellent results so I fugured I give it a try. It was easier to integrate with the Sb29. The "improvement" going from the dynaudio to the peerless was not huge, but it was noticable. As an audiophile I only take the meaning of measurements only so far: Do I build something to sound good or measure as good as I can get it? I would characterize the sound of the speakers to be very good but there is a slight loss of detail in the upper bass. BTW the reason I used a woofer was to not bring the peerless down very low and I did not believe it could have much output at 50hz (ob).
I like the dynaudio myself and it sounded ok. However when another DIY'er (Mdcod) before Dumptruck assisted me with the the original design I ran the data through pcd we did have difficulty getting it to play nice at the upper end with the tweeter. I was advised by Blair that he used the peerless OB with excellent results so I fugured I give it a try. It was easier to integrate with the Sb29. The "improvement" going from the dynaudio to the peerless was not huge, but it was noticable. As an audiophile I only take the meaning of measurements only so far: Do I build something to sound good or measure as good as I can get it? I would characterize the sound of the speakers to be very good but there is a slight loss of detail in the upper bass. BTW the reason I used a woofer was to not bring the peerless down very low and I did not believe it could have much output at 50hz (ob).
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