Need help for my first pair of floorstanders!

[alexnick]

Hi,

I want to build myself a pair of floorstand speakers, and I need your help!
First I should describe what I want: a 2-way floorstand, vented,
using an 8" woofer with a conventional tweeter.
The volume of the box should be ~40-50L with the tuning frequency at FS, for best transient response! The F3 should be around 30Hz!

The problem is where should I cross with the tweeter, low(~1,2khz) or
high(over 2khz)?
Crossing low needs a Cauer Filter, and an waveguide. The Cauer filter
has bigger Group Delay, but it's very steep after XO point!
Crossing high needs a good woofer, high BL/MMS ratio, good off-axis,
low IM distorsion, etc.

I don't have a big budget so I can spend at most ~240E for the woofer and tweeter!

Do you have any suggestions, for the woofer/tweeter pair, XO point, enclosure/filter alignment?

Thanks!

[DIM]

Look for Audax drivers.

[KeithM]

I wouldn't recommend building your own unless you have test equipment, software, or lots of experience. IT may make you feel good to build it all on your own, but it will sound better if a skilled person wold build it. What are your room dimensions? I'd look at the designs already on this site or on zaph's website

[ThomasW]

Look for Audax drivers

Using drivers from a company that's been out of business for ~5yrs probably isn't the best investment...

[JonMarsh]

A design like these comes close to your preferences...



However, they're slightly larger, at 68 liters net internal volume. Crossover in the 1100-1200 Hz region, been done with several different woofers and tweeters, but the preferred design is with RS225 woofer, tweeter either RS28a or Seas Millenium Excel.

Search for "M8ta" on the forum and you'll find lots of info and discussion.

MarkK did a two way with the RS225 and RS28a tweeter in a smaller enclosure, same crossover concept, with very nice results.


Mark K's RS225/RS28A prototype version 6[/QUOTE]




This could be readily adapted to a more conventional ported enclosure floorstanding system.

Audax drivers were withdrawn from the DIY market a while ago, so would be difficult to find, probably impossible to replace.

Personally, I tend to avoid high crossover points in midwoofers becuase the midrange sound seems clearer when you stay within the pistonic region of the driver, and the region where the driver has wide dispersion. An 8" midwoofer starts narrowing in dispersion around 1 kHz, so going much higher isn't a good thing, IMO.

~Jon

[Scott Simonian]

Look for Audax drivers.

Using drivers from a company that's been out of business for ~5yrs probably isn't the best investment...

Yeah.... I was going to say....

[DIM]

You can buy Audax driver in Europe: http://www.audaxspeaker.de/products/prod_tt.htm or: http://www.oregondv.com/. Some of drivers accessible from Zalytron: http://www.zalytron.com/.

[JonMarsh]

That's what we call "NOS" -- new old stock. When they're gone, they're gone.

I used to use Audax back in the 70's; I don't think their offerings for DIY kept up with their competitors in the late 90's. Just my opinion.

~Jon

[DIM]

Is it a "bad" drivers? Or price/quality is to low?

[ThomasW]

Is it a "bad" drivers? Or price/quality is to low?

It's that Audax has been out of business for ~5yrs (they were bought by Harmon International). So anything one buys is technologically dated, and replacement parts are either going to be unavailable or expensive as supply dries up.

[AJINFLA]

Alex forgot to mention that he's in Romania, so the Daytons may not be an option.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=59502

http://www.diyaudio.com/forums/showthread.php?s=&threadid=64095

I stand by the drivers I suggested (2nd thread, post #16) due to their european cost/availability.


Cheers,

AJ

[JonMarsh]

I'm sure theres' a lot of availability issues to consider if one is in Eastern Europe, or SE Asia. Sometimes you have to love the one you're with.... or can be with.

~Jon

[TacoD]

I like Audax units, maybe not as good as current modern designs. Even considering the design is dated I think Audax are offering good units. Particular those HDA offerings are worth to look at.

[alexnick]

Hi,

First of all I have to say that I won't be able to check and answer every day to this topic due to some internet connection problems!
I'll start building these speakers in summer, now I'm trying to choose(with your help) the best solution!

Many people have said Audax, I need the exact driver, not a manufacter. From what I've seen the audax woofers have lower XMAX.

JonMarsh, those Dayton floorstanders are close to what I have in mind,
the problem is the quality of the RS225. Does it really sound good?
What do you think about the higher GD the Cauer filter has?
From your experience, where is better to xover an 8" woofer with an 1" tweeter, lower ~1,2khz or higher ~2khz?
Does IM distorsion become a problem when the woofer moves 14mm(ptp)?

ABOUT THE AVAILABILITY ISSUES: 90% the speakers will be brought by my
cousin that lives in Canada!
(I'm wondering, do they let him get on the plane with a pair of woofers with powerful magnets?)

[JonMarsh]

Check around on MarkK's site for the measurement comparisons he's done with the RS225 and other drivers. The W22 has a better midrange if you cross it high (1500 Hz), but as I point out, if you cross an 8" driver high, you have narrowed dispersion in the upper midrange/lower presence range. The RS225 has lower LF distortion than the W21/22 Seas.

And the GD of the CE filter implemented the way I do it is about the same as a 4th order L-R. A true LR-8 (active, or 8 element passive) has much higher GD.

There are other designs we've done with this, such as the two way with HiVi M8a woofer in a three part article in AudioXpress magazine in autumn of 2003, and also MTM derivative of it. Use the search engine on the forum and you'll find plenty to read about- perhaps an overwhelming amount, if you're having problems with your internet connection.

~Jon

[alexnick]

What do you think about going active with a 24db/octave L-R?
There are advantages, no need for a huge tweeter attenuation ~7db or more!
no phase distorsions, no power waste, no harmonic distorsion, better control and others!
It's easier(cheaper ) to experiment with an active than with a passive xover!

The problem is disadvantages! Are there many?
I'm worried about GD, transient response, etc.
What do you think?

[alexnick]

Hi,

I've made the graphs (digital version). I have them for some time, but
on paper, not excel format.

These graphs are made to show how much a tweeter is stressed when it is
crossed low with an NTM 4th order at 1,2khz / NTM 4th order at 1,2khz +WAVEGUIDE THAT GIVES A FULL +6DB boost from 1,2khz to 4khz, compared to a 2nd order L-R crossed at 2khz(usual for nowadays tweeters!).

I can't upload it, so here's the link:

http://www.hi-fi.ro/fhifi/download.php?id=6642

Please tell me if there's something wrong here!
Thanks!

[BobEllis]

What do you think about going active with a 24db/octave L-R?
There are advantages, no need for a huge tweeter attenuation ~7db or more!
no phase distorsions, no power waste, no harmonic distorsion, better control and others!
It's easier(cheaper ) to experiment with an active than with a passive xover!

The problem is disadvantages! Are there many?
I'm worried about GD, transient response, etc.
What do you think?

I agree with you - now that I have gone active, I am not going back (at least for speakers I intend to keep)

There is, of course, the big stumbling block of needing extra amplifiers. Once you have that taken care of, your comment about being less expensive to tweak is true. For me that also means that I am more likely to keep tweaking, rather than say ""this is pretty darned good, it's finished" :roll:

IIRC, Jon said his C-E filters have about the same group delay as a standard LR4. Looking to push my XO frequencies lower, I've been playing around simulating C-E filters. Now I need to make an adjustable notch filter to compliment my adjustable active filters for real world experimenting. (this Luddite is not going digital just yet) If you are interested in the adjustable active filter, search DIYAudio for MOX. It is a semi-clone of Pass Labs' XVR1.

[alexnick]

bobellis, i'll search on diyaudio for the xover.

What do you think about the area where the tweeter has to play louder?
(in the comparison.xls link)