diyAudio reference speaker project

I would recommend the PL line. Maybe the PL18 if you are worried about it being bass shy. Although the cost is almost double the P17, they are still only $70 which is cheap. I believe, sujectively, that they will be far superior in midrange and the bass will be much faster. Just my two cents.
 
x. onasis said:

Scott C. Blaier's Esquire is the same, right? I'll be using 3/4" MDF as it's what I have, what about the sloped baffle?

To make it easy I've drawn the P13 + D27 design which differs from the Esquire by having a narrower baffle and a tad taller. There is more than enough info there for any newbie to build. The port is in the rear and as long as there's about 40-50mm clearance to the wall, the port will work OK and give the bass some reinforcement. The 5uF cap should be at least metallised polypropylene.
 

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Certainly lot's of interesting ideas here. I agree that my first pass at a suggestion probably didn't fit the "newbie flavor" of this thread - but - there was some mention of being able to start simply and then expand, and there was a wish-list posting which described several versions of increasing cost/complexity projects. The original idea (I think) involved starting small, but with a path for expansion that built on the original work. So, to repeat, :) my idea was this:

1. Build a set of speakers along either the lines of the Dayton BR-1's (mentioned in a previous post) or like the "Dayton Budgets" that Wayne J. designed. These would both use a passive xover as originally designed......

2. Next step would be to try an active xover/gainclone design using the same speakers - with the possible option of adding an additional 5.25 (or 6.5") driver to create an MTM (or other) configuration.

3. Third step might involve adding a Dayton 10" DVC sub (for a mere US$27!) to extend the lower range (while expanding on the active xover and adding additional gainclone to drive it).

In each case, the complexity (and hence - the experience level) increases and provides additional opportunity for experimentation and learning. The key point is that there's a definate "path" which makes use of the previous efforts - sort of "upgrading" along the way while reducing the expense. True - alot of MDF gets thrown out along the way, but that's cheap - and the cost of learning, I suppose....:)

I figure that a single "universal" PCB could be lashed together with the intent of accomplishing the above and it could be populated/rebuilt as you go - and would allow for additional experiments, etc.

The Dayton drivers are inexpensive, "play nicely" together, and are well within the range of the gainclone amps that would be used (in fact, the numbers really fall into place very well once you start crunching them)...........

Just a thought.................

Regards,
Bill
 
I wanted to post an update on my findings, altho I haven't had much time to play with more options.

First impression of this Esquire ala rabbitz:

I now see why many posters wanted to use a midbass that went lower, as a stand-alone speaker, my first listening made me think this would be a good rear speaker in a surround system.

With only a single cap as a filter, the driver's don't begin to show their potential. If this is an only project, and you desire a simple XO with inexpensive drivers, you'd be far better off using 4 or 8, TB 3W-871s.

That said, I'm looking forward to a more refined XO and especially the TLb because....

After only listening to them for about one long poker evening, I then set them up active XO w/Berringer analog, 2-way with a couple attic amps and stereo active subs, and WOW, these drivers shine.

I'll have to try to post some pics, as I used quilted Bubinga for the veneer, and they are cute.
 
x. onasis said:
I now see why many posters wanted to use a midbass that went lower, as a stand-alone speaker, my first listening made me think this would be a good rear speaker in a surround system.

With only a single cap as a filter, the driver's don't begin to show their potential

Hi x.onasis

That's why I used the Peerless HDS (850488) in mine (see post #8)...... much better bass extension.

I'm surprised about the 5uF cap though as it has been stated by planet10 that this is the way to go with these drivers. I think the TLb only use a single cap as well. When you find a crossover that you like, let me know and I'll change the sketch.

If you want to experiment some more, I could email you a series crossover for you to try to see how it compares.

Looks like you're getting right into it.

Cheers
 
rabitz comment

I would not recommend the "series crossover" as indicated in rabitz comment, just because is not any easy to plot the system response for each driver, I mean tweeter + hi pass separated from woofer + lo pass and finally both working together.

In parallel networks you only disconnect the band you want to measure later and work with the other.
 
Re: rabitz comment

Hugo Rodriguez said:
I would not recommend the "series crossover" as indicated in rabitz comment, just because is not any easy to plot the system response for each driver, I mean tweeter + hi pass separated from woofer + lo pass and finally both working together.

In parallel networks you only disconnect the band you want to measure later and work with the other.

Fair comment Hugo.

When I do crossovers I'm only interested in the combined output and not the individual driver. Since moving over to series crossovers (1st order), I find it a lot easier to get the sound I want with a lot less hassles as there is less variables than a parallel network and IMO they sound better, more cohesive and sounds more like a single source, if that's the correct term.

There might be a way of measuring individual drivers in a series crossover..... don't know....... maybe simple as disconnecting the other driver and replacing it with a resistor...... does anyone know?

I think part of the excercise that x.onasis is doing is to try as many different combinations of crossovers, box designs etc so he can document his findings for others to learn from this experience.
 
Hi Rabbitz-

Yes, thanks, do post it.

About the single cap as a decent XO vs bass extension: I kinda feel I've jumped ahead (by bi-amping) in my progressive test/development of our little project (esp. stereo subs), but from what I've seen, it's good to let the drivers break-in before jumping to conclusions.

But I'm convinced, at this point, these drivers are worth playing with in other configs. Send me your XO design, I'll try Blaier's, and order more drivers. I too, would be surprised if Dave's not right.

And check this out:
Measuring series XO

Or Email if you prefer.
 
Re: Re: rabitz comment

rabbitz said:


There might be a way of measuring individual drivers in a series crossover..... don't know....... maybe simple as disconnecting the other driver and replacing it with a resistor...... does anyone know?


Replacing the other driver with a resistor won't work.

Take the driver you don't want to measure, attach a long cord (low DCR) and put it in the closet in another room. Or put it outdoors.
 
coolkhoa said:
Something that's been bugging me:

The Esquire and rabbitz's design have similar volumes. The Esquire uses a 1.625"L port while rabbitz's is about 3.75"L (both have similar port diamaters). My results using WinISD are closer to rabbitz's.

What's the deal?

I'll see if I can get rid of that bug.

Firstly, even though the port diameters look close, they are not and there is quite a difference in length when using different diameters. In WinISD, try again with a 39mm dia and then try with a 32mm dia...... the length will be about half. Also the Fb I used was a little lower.

Secondly, the Esquire uses a different BR alignment. Mine and WinISD used a QB3 where the Esquire uses a SC4 which is quite different. He also did some fine tuning on the port after building which looks like reduced the length further.

Hope this clears it up for you.

You can always do it the long way by calculator:

L = ((1.463 x (10^7 x R^2))/(Fb^2 x Vb)) - 1.463R

L=length in inches, R=radius of port in inches, Fb=tuning freq Hz, Vb=box volume in cubic inches

Software's easier hey!
 
rabbitz said:

Firstly, even though the port diameters look close, they are not and there is quite a difference in length when using different diameters. In WinISD, try again with a 39mm dia and then try with a 32mm dia...... the length will be about half.


WinISD only has preset diameters for the port...couldn't verify (I should try it manually). Yes, the Esquire and your design use different alignments, but consider this: According to the designer of the Esquire, Vifa's literature suggests a QB3 alignment a bit different from yours.

Should we consider this design?
 
coolkhoa said:



WinISD only has preset diameters for the port...couldn't verify (I should try it manually). Yes, the Esquire and your design use different alignments, but consider this: According to the designer of the Esquire, Vifa's literature suggests a QB3 alignment a bit different from yours.

Should we consider this design?

I don't know where the Vifa data comes from. That only uses a 25.4mm port with a length of 38mm and a volume of 5 litres. All of these are variables, so if you change 1 or more the result is going to be different. There's more than one way to skin a cat (sorry cat lovers).

I've used a Vb=5.3 litre with 5.5 actual box volume and the 39mm port size is to get the port noise down.

In WinISD try typing a different port diameter in manually and see what happens to the length...... changes - gets shorter for a smaller dia and longer for a larger dia. Then have a look at the Vent Mach... if the port's too small it will go into the red. I try and keep it below 18.

weeghel, if you want more info have a look at the Wiki and you'll see it in the list.
http://www.diyaudio.com/wiki/index.php?page=Projects