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Multi-Way Conventional loudspeakers with crossovers

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Old 20th March 2009, 11:32 PM   #1
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Default I must be mad

I am seriously considering building an 8" 2 way. I must be mad. Why? Well it has nothing to do with the technical challenges, that I can deal with. It goes like this -

Over the last 35 years of Hi Fi and DIY speakers and amplifiers the biggest problem I have had has been the other half. I don't know what it is with women, but they all seem to have the view that small is good, smaller is better, invisible is perfect, and if it is visible it needs to look like a piece of antique furniture. After 13yrs of education on what good sound is all about, and blowing her away with the sound of the Quad ESL 63, the ex went out and bought herself a Bose system!!! Anyway, afterwards she told me she was not happy with the sound and my speakers sounded much better. Ha, surprise, surprise! The only major win I have had was to convince the the other half that I need to buy a full range eletrostatic. It is large and I had them custom made with solid Walnut sides. The midrange and treble sound is just sublime, best I have heard in my life, but they suck the life out of any amp, and lessor ones end up a blackened charred smoking mess. You think I am joking? NO, believe me it has happened. Now she wants me to sell them because they are too big and heavy AAAGGGHH. We have moved them only once since I bought them so what is the problem?

The last few years have been spent trying to squeeze as much bass as is physically possible from a small driver in a small box. The boxes have been made from solid wood, so they do look rather nice, and the smaller I go, and the fancier the wood, the more satisfied SWMBO is - but real deep bass is non existent - and when I point out they need a sub I get "I am not having one of those big square box subwoofer thingies in my lounge room, if they have no bass that is your problem". Groan!

Well stuff it, damn it, dummy spit time. I never much liked subs for music, they belong with HT. So the next project is going to be BIG. I love transmission lines, have made 4 MLTLs so far, so TL it will be. Bugger it, time to have some real fun. I want serious bass and better efficiency from a bigger woofer. I believe in the KISS principle, so 2 way it will be. That means a driver that can go up to around 2Khz and a tweeter that can crossover low. That immediately rules out ribbons and metal woofers. I already have some North Creek D28 tweeters, and these are perfect. Built like a tank and will cross low and have an exceptionally nice natural sound, quite a step up from the likes of the SEAS 27TBFCG which I have also tried in the past. Woofer selection I have narrowed down to 3. The woofer needs to be available locally, which narrows the field a bit, but I can get Peerless, SS, SEAS, Vifa locally. So, the choice is Peeless Exclusive 8", SEAS CA22RNY and SEAS Excel W22NY001. I have done some TL modelling, and all will work, with the SEAS CA22 a bit more efficient but with sightly less bass extension, but I very much doubt that would be noticable with music since the frequencies are so low anyway. The two SEAS have very nice smooth rolloffs so crossover should be relatively easy. I like that. The Peerless has a breakup peak at 3Khz, but it is not too bad and the driver is tried and proven and well documented. I can't find much on the other woofers, particulalrly the SEAS Excel probably because it is fairly new and expensive, but it looks pretty good to me. The cost of the SEAS Excel in Australia is in the gasp gasp choke region and liable to get me into even more trouble, but I have been looking for an excuse to buy some SEAS Excel for a long time. The tweeter is certainly up in the same quality region as the Excel woofer. George used it with SS and Excel woofers. So, at the moment I am leaning towards the Peerless mainly becasue of the value equation, but I have plenty of time to decide, the latest small speaker project needs to be completed first. And I have a long list of things to be fixed around the house from SHMBO. I guess the bottom line is all 3 are excellent woofers and I should get good results from all 3.

On second thoughts, this could get me into a lot of trouble, especially if I go for the Excel (You spent how much!!?). Could be tricky.

Any comments?
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Old 20th March 2009, 11:44 PM   #2
badman is offline badman  United States
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The Peerless are great drivers. They're limited in high frequency extension, but have a relatively benign breakup, that's easily controlled with a single component (nice to have a lot of shorting paths in the motor, sure keeps things manageable).

But, you'll have a damned hard time getting a tweeter to do a 1kHz crossover. I'd suggest using a fostex FF85k as a midtweet, and you can do a simple, cheap supertweeter at 5k if you're so inclined.
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Old 21st March 2009, 12:30 AM   #3
awedio is offline awedio  United States
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Please don't kill me, but your post had me laughing!

Wow, all three drivers are worthy, I'm sure... I love the look of phase plugs, so that leaves two - of course, I simply have to go with the Excel! I think if it's real bass you're after, it might be lurking in there.

I don't doubt that the North Creek tweeter can go pretty low. You're not the first to cross an 8" to a dome tweeter, ignore the naysayers and use good drivers, I say!!!

I do like the idea of using a widebander and making it a fleshed-out 3"/4"'fullrange (my fave pick would be the 3" tangband bamboo driver, has really nice top octave, at least on-axis) but then you're not making use of your NC tweets. Could you use those as a supertweeter?
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Old 21st March 2009, 01:26 AM   #4
tf1216 is offline tf1216  United States
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I had some help creating a crossover for the W18NX and the D28 tweeters.

I tried to attach crossover schematics.
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Old 21st March 2009, 01:28 AM   #5
tf1216 is offline tf1216  United States
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Tweeter crossover
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Old 21st March 2009, 01:35 AM   #6
DcibeL is offline DcibeL  Canada
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Hi mandoman,
I can assure you that you are not mad . I have done just what you are considering, using a Peerless Exclusive 830884, and a Peerless HDS 810921.

See my project here:
A new project: HDS Peerless towers

The biggest hurdle with such a speaker is that you do have to use a tweeter that can perform well at low frequencies, so you can crossover at a low enough frequency (I used 1.5kHz) such that beaming isn't an issue. Also, it is a bit more difficult to get good polar response, or in other words good on-axis phase alignment at the crossover frequency, because the acoustic centers of the drivers are further apart.

If my project above interests you, all I can say is that it sounds absolutely sublime. I get bass down to 30Hz, not as much power handling as it could have with higher tuning, but it plays more than loud enough for my needs. Every single person who has listened to this speaker has asked me where my subwoofer is

Good luck with your project.

tf1216, with high end drivers like those, that crossover schematic is of no use unless it has the rest of the project to go with it, especially the baffle size.
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Old 21st March 2009, 01:50 AM   #7
tf1216 is offline tf1216  United States
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Good point Dcibel.

We built a 0.5 cu. ft. to match the PE cabinet. I am trying to find the rest of the details on my computer. We went with a relatively high port tuning which we are in the works of changing that. This speaker can be played very loud and sounds remarkable doing it.
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Old 21st March 2009, 03:22 AM   #8
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Sounds like the perfect time for IB subs into the attic! You can get below 20hz and still have modest size speakers. The wife may not even notice the 15 inch circles on the ceiling......
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Old 21st March 2009, 04:12 AM   #9
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Well thanks for all the encouragement, and I am glad I made someone laugh. I guess some of you married folk can probably relate to my experience. I'm not really complaining, I have enjoyed making smaller speakers from solid wood because I love working with wood, but it is time to do something different and challenging. If I do go with the Excel woofer, then that will have to wait a while so I can save up the cash. The dog has been ill and the vet bill ain't funny. Just picked him up from the doggy hospital and nearly passed out when given the bill, and he is still not well so that might not be the end of it. Damn stupid dog, why do they eat rotten things that make them ill!

1Khz crossover, that's bit extreme isn't it? The North Creek will go down to 1.6Khz according to the specs, so should be feasible. Another alternative is something like a Bandor or Alpair 6 or 5, but they are inefficient, particularly the Bandors which I have used before. The current project uses Alpair 6, so I will get a good idea of what they sound like, an active crossover would solve the efficiency mismatch problem. I will check out DcibeL's project, sounds interesting, thanks for the link and encouragement. The Peerless HDS tweeter is another possibility, but increases the cost since I already have the Northcreek, and I have not yet heard the Peerless tweeter. But then you have done the hard yards with the crossover, and that is the hardest bit. Another possibility is an active crossover with steep filters, I've done that before and have a small amp suitable to power the tweeters, so should not be a problem. If I go active then is probably worth going the whole hog and use the Excel woofer. Mmmm tempting.

By the way, we don't have attics in Australia, just a roof space that gets so hot in summer it would melt the glue, so good idea, but not practical. We have a new house on the coast with a family room, so these speakers should go into the family room. She can have the lounge room, but the family room is mine, mine mine. Mmm, on second thoughts, maybe not, let's be honest, I'm kidding myself. Last resort is to put them in the workshop and live out there. I like good sound while I work. A large cabinet will have it's own challenges and is not really suitable for solid wood because the wood movement will be too big to handle, so most likely will have to be MDF. Bare MDF won't go down too well with SHMBO, to say the least, so I will have to think hard about the finish. Then again, bare MDF is fine for the workshop! That's MY territory.
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Old 21st March 2009, 05:29 AM   #10
Renron is online now Renron  United States
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Not exactly what you are thinking of but, Planet 10 and ScottMoose have redesigned the MTM Thor from Seas. Not a 2 way but it makes Lots of Bass. Plenty for music. Give the Thors a look see.
Ron
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