First Build Dayton DA175 and Vifa BC25SC06-04

[alg460]

Newbie here to speaker building. I had started a thread here and I was planning to use some cheap MCM woofers I had laying around for 5 years. Because of the helpful people here I learned that it was a bad idea. In fact I learned so much from that post that I went from speaker illiterate to speaker expert and I now know more than every one of you here. Just kidding but I did learn a lot.

Jreaves (and others) suggested I get my head out of my you know what and do it right and go with something better. It was also suggested that I start a new thread for the build as a project using the Dayton DA175 7" may be of interest to others. The Vifa BC25SC06-04 is being used simply because I have them. The rest is on order.

I think Jreaves will be posting here with his expertise on the xo and such and I will update on my building progress.

A big thanks to all here
Tony

 

[Inductor]

The Dayton RS180-8 7" will give you probably more freedom in the crossover region.
Dayton Audio RS180-8 7" Reference Woofer | 295-355
This because/if you are using the tweeter you mention (Fs 1390Hz).
The Madisound Speaker Store
The midwoofer driver DA175-8 7" has better frequency extension for a woofer but the RS has lower Le (0.74) and higher Xmax (6.0mm) working better with a higher crossover frequency.

 

[Inductor]

They made it work here with a different woofer Peerless 832873 HDS 5-1/4" so maybe it's possible with some engineering. I don't know how are the results... it's all about testing.
MT Peerless 832873 and Vifa BC25SC06-04 1"

A different project: Linkwitz Lab PLUTO project

 

[giralfino]

IMHO, you can succeed using the DA175 and the BC25SC06, but it'll be difficult. The harmonic distortion and frequency response of the woofer will dictate a steep 2KHz crossover, and for the tweeter 2KHz could be too low, but in its favour it has a mild horn loading, allowing a lower crossover point respect a "normal" 1" tweeter. I'd try a LR4 crossover at 2-2.3 KHz.
Another woofer to consider is the Peerless 830657. You can see an use here: https://sites.google.com/site/undefinition/tarkus Please note the notch used to tame the breakup.

Ralf

 

[alg460]

Well as I said I'm new to this. I hope Jreaves chimes in here. He came up with a crossover and some response plots and said it would work. The crossover looks slightly complicated. On the other hand if there is a tweeter that's a better match I'll buy them.

 

[mikejennens]

Here is a project using the DA-175 and a Dayton Audio tweeter. I built these and was very impressed. There are even some tweaks for it on line.
Mike

Speaker Project - Karma Indignia -- 8/23/2011

 

[alg460]

I think I like the old days better. Back in the 60's we just took a speaker and maybe a tweeter, put it in a box and called it a day. I have a huge bookshelf full of old electronics/audio magazines from the 50's - 60's. They are full of speaker construction projects from basic to weird to exotic. Most of them suggest a specific woofer (or driver as we now call them) but imply that most any speaker of the same size should work for the project. Crossovers were simply a capacitor on the tweeter but some did have the classic text book second order 12db crossover. Back then there was nobody that could listen to it and say it don't sound good (within reason) and there were one in a billion that could measure it. Did we all suffer back then with horrid (tiring as some say) sounding speakers? Were we all just naive? Where did this need for absolute perfection come from? Most people could not tell the difference from a good speaker and a perfect speaker - myself included. A crappy speaker would be evident to most.

I'm really not being sarcastic towards anyone - just wondering why its so critical now and nothing short of perfection will be worthwhile.

I think I'm just going to abandon my project and just shelve the $70 worth of DA175's I just bought. Or if anyone can use them you can have them for the cost of shipping.

 

[dumptruck]

Unless you are literally the best speaker designer in the world, somebody will always have a better idea, and nearly everybody will think they do. Pick and choose what advice to follow and how far to follow it as you see fit. I'm sure your drivers can be made to work alright together. If you really want to ditch your woofers for the cost of shipping, though, I'll take 'em.

Yes, good speakers are much, much better now than they were in the 60s. Bad speakers are still bad.

 

[jReave]

Tony, no .... don't give up!

Guys, he's not seeking the Holy Grail of Audio Nirvana here - he just wants to make some speakers that sound good. I'm not sure that he sits down to do much critical listening as apposed to wanting it more for background music. The drivers are already purchased and I've already worked out a couple of xo's for them. This thread was to document his build and thus make it available to anyone else.

The xo point is a little tight with this tweeter but it's been used with good success crossed at about 2200Hz in the Stentorians - Speaker Design Works. And Zaph has good things to say about the DA175.

First graph below is with pretty simple 2nd order electrical xo's with an extra capacitor on the woofer inductor to kill the woofer resonance. The woofer is in 55L tuned to 33Hz. It should be a good starting point. Second graph adds a couple more filters to smooth it out a little more.

Tony, I'm busy for the next couple of days so can't post all the details so..... think about it and see how you feel by then and let me know if you still want to continue with the project.

 

[goody75]

If you're open to tweaking the woofers, IIRC BudP had a very high opinion of the DA175's after EnABLing them. I think there is a reference in the EnABL - Listening Impressions thread.

 

[goody75]

... and I think it fixes any crossover problems too.

 

[Inductor]

Tony, hope you get it right.
The Dayton DA175 woofer has great LF extension, in a proper BR tuned enclosure.

 

[alg460]

Tony, no .... don't give up!


Tony, I'm busy for the next couple of days so can't post all the details so..... think about it and see how you feel by then and let me know if you still want to continue with the project.

Ok I wont give up. Just got a little frustrated there. Seems all I have been doing it thinking about speakers and trying to learn.

I mentioned the 60's because back then it seems even the box size had no science behind it and was trial and error or guess work for most people. Nowadays the box is simple. And there was no info back then on crossovers other than they were just simple high and low pass filters

I sure your crossover will sound fine to me. But after the speakers are done I want to take one of them and tinker with the crossover. I want to hear it without baffle step compensation. Then I want to hear what cone breakup sounds like and what a dip or peak in the wrong place sounds like. By comparing what I hear to the other untouched speaker I might be able to better understand crossovers and why so much effort is put into them. From there who knows, maybe I'll be able to design my own.

Tony

 

[ODougbo]

Tony,
Have you cut the front baffle? if not you can move the tweeter up just a bit, you may want to up-grade the tweeter someday.
I.e. many tweeters are 4 - 1/8" so place your smaller tweeter up a bit higher, with this in mind.

Think about rolling the front baffle edge with a router, it helps a lot

Remember, a lot of the recommendations are 50% yes - 50% no, there's a better way.

Now this front port is a good example, I'm sure it would fine in a 3' tall box, not like the mid-range is going to be a problem.

 

[ODougbo]

Tony you bought plywood - yes?

here's a nice/easy way to roll an edge - use bass wood, very soft, easy to sand. Clamp strips of wood to the panels first; study the direction of the grain, think ahead which way you'll be routing.
You don't want to go backwards into the grain.

These are really old, gave them a new box:
http://www.diyaudio.com/forums/multi-way/242904-vifa-m18wo-09-08-revisited.html

 

[giralfino]

Have you cut the front baffle? if not you can move the tweeter up just a bit, you may want to up-grade the tweeter someday.
I.e. many tweeters are 4 - 1/8" so place your smaller tweeter up a bit higher, with this in mind.

One of the benefit of a small tweeter is that it can have a lower C-C distance, you should use this benefit.
If you plan to change tweeter someday, you should use a removable baffle, it has also the benefit of easily working inside the cabinet (stuffing, mods on the crossover and the like).

I sure your crossover will sound fine to me. But after the speakers are done I want to take one of them and tinker with the crossover. I want to hear it without baffle step compensation. Then I want to hear what cone breakup sounds like and what a dip or peak in the wrong place sounds like. By comparing what I hear to the other untouched speaker I might be able to better understand crossovers and why so much effort is put into them. From there who knows, maybe I'll be able to design my own.

That's a great plan. I bet you'll learn a lot.

Ralf

 

[alg460]

Tony,
Have you cut the front baffle? if not you can move the tweeter up just a bit, you may want to up-grade the tweeter someday.
I.e. many tweeters are 4 - 1/8" so place your smaller tweeter up a bit higher, with this in mind.

Think about rolling the front baffle edge with a router, it helps a lot

Remember, a lot of the recommendations are 50% yes - 50% no, there's a better way.

Now this front port is a good example, I'm sure it would fine in a 3' tall box, not like the mid-range is going to be a problem.

I have not cut anything yet. Good point on leaving room for a bigger tweeter. I probably should just get tweeters now that are a better match for the DA175 but that would mean I'd be driving jReave's crazy and I'd have to start a new thread. Probably be a good learning experience for me sticking with the Vifa and it will be a test of jReaves skills and patience.

Tony

 

[alg460]

One of the benefit of a small tweeter is that it can have a lower C-C distance, you should use this benefit.
If you plan to change tweeter someday, you should use a removable baffle, it has also the benefit of easily working inside the cabinet (stuffing, mods on the crossover and the like).


That's a great plan. I bet you'll learn a lot.

Ralf

Thanks Ralf

For this one I do plan on having a removable baffle since I have no clue what I'm doing.

Tony

 

[Einric]

I built the Silver AL's "UE" with the DA175 & the DC28F.
I have found .8cuft @ 33hz tuning w/ light stuffing is really great.
The sims really show LF extension @ 2cuft but I think you will run into excursion problems well before rated power input.

 

[alg460]

Tony you bought plywood - yes?

here's a nice/easy way to roll an edge - use bass wood, very soft, easy to sand. Clamp strips of wood to the panels first; study the direction of the grain, think ahead which way you'll be routing.
You don't want to go backwards into the grain.

These are really old, gave them a new box:
http://www.diyaudio.com/forums/multi-way/242904-vifa-m18wo-09-08-revisited.html

I did buy plywood. Its Poplar. They were down to one sheet of birch and it looked beat up and I don't like oak so I bought the poplar

I'm not sure what you are saying about rolling the edges. I'm out of time right now but I am going to PM you tomorrow AM.

Tony