Wow. This is a milestone for me. I have learned enough here in the last few weeks that I actually think I know what you are talking about.
Lets see I think its something about too big a box and/or below the tuning frequency the cone excursions can exceed Xmax. Something along those lines. How my doin guys. Am I learning.
I want the 2cu ft box for aesthetic reasons. I was thinking I put a partition inside to bring it down to 1.2 cu ft.
Tony
For small rooms (up to 20'x20') the Silver Al's "UE" are GREAT.
Above that a sub is really needed for higher volumes.
BUT....what do you expect from a pair of 7" woofers, especially when they are budget drivers?
I really do enjoy them on my F4 I have found that running them "full range" (20-20k) they run out of x-max at about 25W or so below 35hz, hence the subwoofer.
Above that a sub is really needed for higher volumes.
BUT....what do you expect from a pair of 7" woofers, especially when they are budget drivers?
I really do enjoy them on my F4 I have found that running them "full range" (20-20k) they run out of x-max at about 25W or so below 35hz, hence the subwoofer.
I would shy away from any more than 1cuft.
Zaph Audio showed that 1cuft @ 31hz was about the lowest you want to go and a pretty sweet spot to be for response v.s. power handling.
Here is a quick comparison with 1.2cuft @ 30hz VS .8cuft @ 33hz.
The extra 50% volume only gains you 3hz extension @ -6db down, at the expense of control an power handling.
Zaph Audio showed that 1cuft @ 31hz was about the lowest you want to go and a pretty sweet spot to be for response v.s. power handling.
Here is a quick comparison with 1.2cuft @ 30hz VS .8cuft @ 33hz.
The extra 50% volume only gains you 3hz extension @ -6db down, at the expense of control an power handling.
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Those are nice looking. My wife would love them. She would have a place on the bottom to put a vase or figurine or something there.
Tony
I can't tell a lie 
but I was thinking about the DC28F, a DIY-er brought a set over the other day, they sounded great.
That said, I've always like the closed back dome/soft dome tweeters, I guess it is just what you get used to.
Spit and Sizzle, now who say's that ??
I agree, however they are still very natural sounding.
Einric.....
but I was thinking about the DC28F, a DIY-er brought a set over the other day, they sounded great.That said, I've always like the closed back dome/soft dome tweeters, I guess it is just what you get used to.
Spit and Sizzle, now who say's that ??
I agree, however they are still very natural sounding.
Einric.....
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Well..... my Great Christmas Adventure of 2013 only lasted 27 hours. I was a bit disappointed. An ice storm moved through the area on the weekend and power went out for hundreds of thousands but I got it back yesterday. Others are still without and I feel for them ........ but I had fun anyways.
Well, back to the subject at hand. Here's what I've worked up for you Tony.
I changed the baffle in these sims to 11.5" wide and 34" tall. The center of the tweeter should be 3" from the top; the center of the woofer, 9". Sides and top edges have a 1/2" roundover.
There have been some good suggestions re box size and xmax limitations. Since you were kind of set on the 60L or so cabinet size, I thought half that (about 28L) might be a good volume to go with for 1 woofer because you'll be getting the same response if you end up going with 2 of them in the same cabinet. Just a thought though. For these sims, I used the 34L (about 1.2cft) that you seem interested in but tuned it to 37Hz, a little higher than other suggestions because I wanted to boost the LF a little more in SPL to match your small deficit in hearing (mentioned in your 1st thread). But tuning I leave up to you. These xo's should work with whatever you decide to go with. Also, with a removable baffle, another way to shrink your internal volume other than a divider of some sort (which must be air-tight btw) is to fill the cabinet with something. In your case something large like a bag or 2 of sand for example.
Below is the simpler xo for you with the transfer functions again and the xo schematic. The 1st graph zooms in a little more on the FR this time so that you can see the deviations from flat a little better. Second order for the xo's at about 2500Hz with a couple of extra parts to knock it into shape. Tony, for you, mostly just look at the summed response which is the black line but I've included individual driver responses (blue and red), phase (light blue and sort of brown), the reverse null (grey) and the power response (green) for anyone else that might want to see them.
Here are a couple of pieces of info that might help you make evaluations:
Three dB is usually the minimum change in SPL that's required to be able to notice a difference perceptually. So if the deviation in the FR is less than 3dB, it's more or less considered close enough to flat. Personally, I think 3dB is overstating it. I'd call it at 1.5 to 2dB, for me at least anyways. (My receiver changes volume in 1/2dB increments - and yes, that's a lot of clicking sometimes)
A peak in the response is generally considered more noticeable or more offensive than a dip.
We tend to lose high frequency hearing as we age so you may or may not be able to hear what happens above 13,000 to 15,000Hz or so.
Although a flat FR is generally considered as the ideal, there are reasons why in certain cases you might want to deviate from that - the most important being because you prefer it that way.
Probably the most common thing you'll see is increases in the LF and HF so that the FR looks like the start of a smile. YMMV
Not to worry about taxing my patience - if I didn't want to help people here, I wouldn't be posting. Now that I have the sims done, it's a real simple matter of making changes to them. So if you want to see what happens with other values, just let me know and I'll post the response.
Well, back to the subject at hand. Here's what I've worked up for you Tony.
I changed the baffle in these sims to 11.5" wide and 34" tall. The center of the tweeter should be 3" from the top; the center of the woofer, 9". Sides and top edges have a 1/2" roundover.
There have been some good suggestions re box size and xmax limitations. Since you were kind of set on the 60L or so cabinet size, I thought half that (about 28L) might be a good volume to go with for 1 woofer because you'll be getting the same response if you end up going with 2 of them in the same cabinet. Just a thought though. For these sims, I used the 34L (about 1.2cft) that you seem interested in but tuned it to 37Hz, a little higher than other suggestions because I wanted to boost the LF a little more in SPL to match your small deficit in hearing (mentioned in your 1st thread). But tuning I leave up to you. These xo's should work with whatever you decide to go with. Also, with a removable baffle, another way to shrink your internal volume other than a divider of some sort (which must be air-tight btw) is to fill the cabinet with something. In your case something large like a bag or 2 of sand for example.
Below is the simpler xo for you with the transfer functions again and the xo schematic. The 1st graph zooms in a little more on the FR this time so that you can see the deviations from flat a little better. Second order for the xo's at about 2500Hz with a couple of extra parts to knock it into shape. Tony, for you, mostly just look at the summed response which is the black line but I've included individual driver responses (blue and red), phase (light blue and sort of brown), the reverse null (grey) and the power response (green) for anyone else that might want to see them.
Here are a couple of pieces of info that might help you make evaluations:
Three dB is usually the minimum change in SPL that's required to be able to notice a difference perceptually. So if the deviation in the FR is less than 3dB, it's more or less considered close enough to flat. Personally, I think 3dB is overstating it. I'd call it at 1.5 to 2dB, for me at least anyways. (My receiver changes volume in 1/2dB increments - and yes, that's a lot of clicking sometimes)
A peak in the response is generally considered more noticeable or more offensive than a dip.
We tend to lose high frequency hearing as we age so you may or may not be able to hear what happens above 13,000 to 15,000Hz or so.
Although a flat FR is generally considered as the ideal, there are reasons why in certain cases you might want to deviate from that - the most important being because you prefer it that way.
Probably the most common thing you'll see is increases in the LF and HF so that the FR looks like the start of a smile. YMMVNot to worry about taxing my patience - if I didn't want to help people here, I wouldn't be posting. Now that I have the sims done, it's a real simple matter of making changes to them. So if you want to see what happens with other values, just let me know and I'll post the response.
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So looking at the FR above with the simple xo, 2 things stand out - the peaking between 400 and 1000Hz and the rising HF response at about 7000Hz. If you want to see what it will sound like without these, I've added 2 extra filters to tame them (and I think 2 other tiny little changes too - and yes, guilty as charged in seeking perfection here, I just can't help myself ), but I'd say start with the 1st one and go from there.
), but I'd say start with the 1st one and go from there.Attachments
Wow. I'll have to study those curves for an hour. I'm going to build the simpler xo first and after a week or so make the second just to see if I can hear the difference. I mentioned 1.2cu ft because thats what the parts express website stated was optimum. Whats weird is winisd gives me 55L for the DA175 ?????. I'll put a partition in my box for the 1.2 cu ft because eventually I'l probably want to experiment with adding a second da175. What does that do to the xo?
Thanks for everything
Tony
You're welcome, Tony.
Like I said in your 1st thread, there are all kinds of possible box alignments. The box programs' might recommend what is optimally flat - the lowest F3 possible without any peaks in the response. I use an Excel program (Unibox) which suggests an optimal volume of 58.9L for an F3 of 23.33Hz when the walls are covered with damping material and I'm using Zaph's measured data. Trouble with that is you can't get much SPL before cone excursion gets too large so it sounds like PE found 1.2L to be the best compromise. Don't take it as written in stone. Again for you, you may want a 2 to 3dB boost in the bass region. I found 28L tuned to 40Hz might work well since that will sound the same as 2 woofers in 56L tuned to 40Hz.
There are a couple of different ways to add in the 2nd woofer - I'm going to suggest that you do it in a manner in which the 2nd woofer fills in the 6dB of bass that you lose through the baffle step loss (what's called a 2 1/2 way speaker). To do that you want to start the 1st woofer roll-off at a higher frequency - so you'll need a smaller value inductor - and then you use a larger one on the 2nd driver. Physically, you just put the 2nd woofer below the 1st one so you can use the same baffle. I'll post some more graphseek and work up the xo changes for you whenever you're ready. Unless you want to order all your parts at the same time, then give me a couple of days and I'll see what I can do.
Cheers and Merry Christmas
Like I said in your 1st thread, there are all kinds of possible box alignments. The box programs' might recommend what is optimally flat - the lowest F3 possible without any peaks in the response. I use an Excel program (Unibox) which suggests an optimal volume of 58.9L for an F3 of 23.33Hz when the walls are covered with damping material and I'm using Zaph's measured data. Trouble with that is you can't get much SPL before cone excursion gets too large so it sounds like PE found 1.2L to be the best compromise. Don't take it as written in stone. Again for you, you may want a 2 to 3dB boost in the bass region. I found 28L tuned to 40Hz might work well since that will sound the same as 2 woofers in 56L tuned to 40Hz.
There are a couple of different ways to add in the 2nd woofer - I'm going to suggest that you do it in a manner in which the 2nd woofer fills in the 6dB of bass that you lose through the baffle step loss (what's called a 2 1/2 way speaker). To do that you want to start the 1st woofer roll-off at a higher frequency - so you'll need a smaller value inductor - and then you use a larger one on the 2nd driver. Physically, you just put the 2nd woofer below the 1st one so you can use the same baffle. I'll post some more graphs
eek and work up the xo changes for you whenever you're ready. Unless you want to order all your parts at the same time, then give me a couple of days and I'll see what I can do.Cheers and Merry Christmas
Thanks again. The DA175's arrived and I kind of - sort of tried out one of them. I put one in a make shift box that I previously tinkered with the MCM's in - about 17L. Using parts on hand I made a close approximation of your simpler crossover but I used 6.8 UF on both the LP and HP. For inductors I only had a 1mh for the LP and a 0.4mh for the HP. It sounds pretty darn good to me. The DA175's go way lower in bass than the MCM 55-1170 (the stated fs of the mcm at 40 hz is a lie). My own test of the DA175's fs comes in at 35Hz - a little lower than specified.
The SPL will probably be adequate for me if I had a left and right speaker instead of just one. But I have to ask. What other benefits are there to adding a second DA175 besides spl.
Guess I'll get started on building my boxes and ordering some xo parts. I think I'm going to like these.
Tony
Ah, that makes me smile.
I hope you have some resistors on the tweeter too. I input your values into my sims with my tweeter padding and you can see what the result looks like below. Not bad. It's very similar except the driver phases aren't as well aligned in the xo region (arrowed) (so in other words, the 2 drivers are playing the same thing in the xo region but not exactly at the same time) and you now have a bit of a peak at about 1800 Hz too.
Adding a 2nd woofer's primary benefit is the additional SPL. But what that means is that for the single woofer speaker to play as loudly as the dual woofer speaker, the single woofer has to work harder - it has to play 6dB louder than each of the other woofers in the other speaker (and the amp needs to work a little harder too). And since distortion increases with a driver's SPL, that means that the 2.5 way speaker is also going to be a little cleaner sounding. So that's about it. Louder and a little cleaner especially at louder volumes.
I hope you have some resistors on the tweeter too. I input your values into my sims with my tweeter padding and you can see what the result looks like below. Not bad. It's very similar except the driver phases aren't as well aligned in the xo region (arrowed) (so in other words, the 2 drivers are playing the same thing in the xo region but not exactly at the same time) and you now have a bit of a peak at about 1800 Hz too.
Adding a 2nd woofer's primary benefit is the additional SPL. But what that means is that for the single woofer speaker to play as loudly as the dual woofer speaker, the single woofer has to work harder - it has to play 6dB louder than each of the other woofers in the other speaker (and the amp needs to work a little harder too). And since distortion increases with a driver's SPL, that means that the 2.5 way speaker is also going to be a little cleaner sounding. So that's about it. Louder and a little cleaner especially at louder volumes.
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Oh I never call back and order a second set - or quadruple the order
How do yo like the Dayton speaker, made well? They do a nice a job on everything I've seen from them.
I still have to PM you about rounding the baffles. With Christmas crap I got tied up. See my next post about what I think of the Dayton's.
Tony
Ah, that makes me smile.
I hope you have some resistors on the tweeter too. I input your values into my sims with my tweeter padding and you can see what the result looks like below. Not bad. It's very similar except the driver phases aren't as well aligned in the xo region (arrowed) (so in other words, the 2 drivers are playing the same thing in the xo region but not exactly at the same time) and you now have a bit of a peak at about 1800 Hz too.
Adding a 2nd woofer's primary benefit is the additional SPL. But what that means is that for the single woofer speaker to play as loudly as the dual woofer speaker, the single woofer has to work harder - it has to play 6dB louder than each of the other woofers in the other speaker (and the amp needs to work a little harder too). And since distortion increases with a driver's SPL, that means that the 2.5 way speaker is also going to be a little cleaner sounding. So that's about it. Louder and a little cleaner especially at louder volumes.
I probably have more than a peak 1800. The xo is wrong, the cabinet volume is wrong and the cabinet width and tweeter spacing is all wrong. I just could not resist throwing these things in a makeshift box/xo and hearing them.
With that said, and I'm such a newbie to this that my opinion means nothing, I am impressed with the DA175's.. I never had a high end speaker but as I said in one of my posts I did have some 1960's Bozak 12" coaxial speakers that I put in my own box. At the time they were supposed to be good but who knew. The DA175s put the bozak 12er's to shame with their low end punch and I would expect when in the proper box with jReaves xo they'll be even better.
ODougbo: I would not know if their well made. One thing I noticed is they have a rear gasket that fits inside the rear stamped frame. To me the frame seems thicker than the gasket so the gasket is probably useless. Beyond that, those old Bozaks had some kind of thick felted paper cone and the frame seemed to be more massive maybe even casted but I'lll have to dig them out to see.
Tony
Did you order your tweeter caps? These are very nice - and very reasonable $$
dayton 6.8 - Parts Express Ships Fast and Ships Free.
Adding hardwood to the speaker panels is just another step. I'm sure it can be done other ways, but gluing them on the early stages makes a lot of sense. Also keep your wood flat, don't let it bow/bend/warp - arrow straight wood is much easier to work with.
Rip the solid wood 3/4 x 3/4 make sure it just a bit thicker than the ply, do not undercut it and hope it will come out smooth with sanding. This is a good time to set up a router table and use flush trim cutter to a near perfect fit.
You can pick up poplar up at HD, look for grain pattern you can work with, also white as possible, green tint is an inherent problem with poplar.
If you can find ithe Bass wood it is even better for gluing on strip edges, as mentioned, its soft and easy to sand.
When you start cutting, send some pics, there are many more ideas to enhance you speaker build.
dayton 6.8 - Parts Express Ships Fast and Ships Free.
Adding hardwood to the speaker panels is just another step. I'm sure it can be done other ways, but gluing them on the early stages makes a lot of sense. Also keep your wood flat, don't let it bow/bend/warp - arrow straight wood is much easier to work with.
Rip the solid wood 3/4 x 3/4 make sure it just a bit thicker than the ply, do not undercut it and hope it will come out smooth with sanding. This is a good time to set up a router table and use flush trim cutter to a near perfect fit.
You can pick up poplar up at HD, look for grain pattern you can work with, also white as possible, green tint is an inherent problem with poplar.
If you can find ithe Bass wood it is even better for gluing on strip edges, as mentioned, its soft and easy to sand.
When you start cutting, send some pics, there are many more ideas to enhance you speaker build.
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Well we knew the frames were stamped from the pic on PE, no surprise there; high percentages of speaker are made that way - to keep costs down.
Gaskets:
Typically supplied gaskets are very handy they should probably work for you. If not, PE sell gasket tape - I've just been making them out of cork lately and smile when I pull the driver out for another project.
Gaskets:
Typically supplied gaskets are very handy they should probably work for you. If not, PE sell gasket tape - I've just been making them out of cork lately and smile when I pull the driver out for another project.
Oh God no. Please don't send the poor guy to that Enabl thread. He's already having enough problems without having to deal with that mumbo-jumbo
He needs someinfo that really works not subjective voodoo.
Well I got all my wood cut up and I'm building boxes. My intent with these was to cover the boxes with a black, satin finish laminate and stain the baffles a gunstock like color. I'm confused about this rounding the corners of the baffle. I looked at various speaker projects on the web and noticed many don't have rounded edges but many do. I can't make laminate go around a radius. So whats the deal about rounding the edges?
Here's some pics. I'm going to add two 3/4 X 3/4 strips along each side to screw the baffle to so it can be removed. The back will not be removable.
What else I need? Corner braces maybe?
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