Home Theater Forum and Systems banner

101 - 120 of 157 Posts

·
Registered
Joined
·
205 Posts
Discussion Starter #101
Almost there - need to make "tray" bases to conceal the xo parts.

New: solid wood vents (vs mdf) and extra wood strips to finish end grain.

Sound? very nice, easy to listen to, remarkable solid/punchy bass; easy to hear movie dialogue.
 

Attachments

·
Registered
Joined
·
205 Posts
Discussion Starter #103
From an avid speaker grue! a fair assessment:

Take it into context that we are talking $35 tweeter and woofer here. A lot of speakers in this range are just plain bad. These may just be the winners at the price point. I have not found a cheaper tweeter that I can stand at all, let alone hold it's own and the SF is a similar bargain. Even at this price, the quality of the crossover components is evident, not wasted. Something to think about. Full disclosure, I just don't like the XT25 much, feeling $20 more for a Seas is well worth it IMHO. A better woofer is a bigger jump. These are a well matched pair and when properly executed will make a very good showing of themselves.

I can verify these are getting pretty good. We were listening with no sub. Their f3 is in the 60 or so range so his description of real base is valid. Not the sub part, but real. :) The cabinets are a bit oversize (12.5L), but instead of a peaky roll-off as you expect in a too-big ported box, they sound a bit more like a sealed box rolling of easy to blend with the room. Doug's port design here needs further investigation to see what it is doing. The asymmetry bothers me in concept, but it seems to work.

Joni Mitchel (Morgantown) did pretty well being properly balanced. Joan Baez (Diamonds and Rust) was just a tad off. close. Their voices are just plain hard to get right. Harry James will show you why you may want to spend twice as much for a tweeter. Crank them high enough for Gliere (The Red Poppy) and you see where paying 5 times as much for Scan Speak comes into its own. Imaging was hampered by the too close bright wall. It was focused, but constrained within the speaker width. Real living rooms do have limitations.

[He left out BACH Toccata & Fugue / First Church...crazy!!! I laugh out loud every time I hear it]

These are just about ready for prime time. Maybe a bit of creative "Penguin" paint. Just one pair. (The WAF would not be good but the photo would be great)

Those without test tools should be heartened as he has done these entirely by ear.

[FYI Madisound crossover]

Odougbo
 

·
Registered
Joined
·
205 Posts
Discussion Starter #104
Well I was close....looking at my own photo, I see one wire needs to moved :eek:

Grounded the woofer notch filter on both sides :rofl: (which will be an easy fix).

It did sound okay, maybe 3 parts I don't really need :dontknow:
 

Attachments

·
Registered
Joined
·
205 Posts
Discussion Starter #106 (Edited)
Some feq in the mid I suppose; it didn't sound bad at all without it (but all fixed now). I'm thinking the big coil is 95% of it.

Ordered some more matrix boards, at least I have a good starting point now :D
 

Attachments

·
Registered
Joined
·
1,001 Posts
The notch filter is noticeable only when the particular frequency being attenuated is being played.
An unfiltered frequency requiring a notch filter, generally creates listener fatigue when your ears identify the obtrusive "peak" and attempt to avoid it by adjusting inner ear responses or aggravating the listener enough that he removes himself from the irritation . . . . decides he's going to do something else other than listen to those irritating speakers. Even listening to one's wife might be more enjoyable if the frequency peak is loud enough say 6db or more.
A 6.5 inch woofer usually has a peak in the area of cross-over ie: about 2500Hz. The better woofers have a peak somewhere in the 4-6 db range. Occasionally a less expensive woofer will have an additional peak around 300-500 Hz. It's difficult to recognize by ear that a particular driver has a peak. Generally a sweep/graph has to be made and recorded to recognize a peak that needs treating.
A 3 part notch filter (capacitor, resistor, and inductor) can be adjusted for frequency width (cap and inductor) and depth of cut (resistor).
Algorithmic formulas can be designed to suggest the filter component value but final adjustments are made while installed in circuit.
The "better" speakers have the frequency response adjusted to eliminate peaks and have crossovers that allow the response to minimize comb filtering effects and match phase across a wide frequency band.
All this electronic wizardry comes at a price.
 

·
Registered
Joined
·
205 Posts
Discussion Starter #108 (Edited)
I do wonder how effective a 3 part circuit can be, seems a bit mysterious. One can always clip lead over to see if it is really hitting the mark.
I've have speakers that just drove me crazy, more than the ball-n-chain :heehee: These grab your attention, the imaging, rich bass lower register are the highlights.

The Silver Flute woofer is impressive, as my buddy pointed out, they can work in a box slightly larger than simulation(s), and work fine. I would only use them with a 1.5mh series inductor.

I really like this idea of an outside xo, I don't want all those parts inside my box :rolleyesno:

update - crazy imaging with the new xo, WOW! also getting more sounds than I've ever heard, I'm really liking these!!
 

Attachments

·
Registered
Joined
·
1,001 Posts
You've got some nice looking units. Well done.
It's useful to keep the X-over outside the box until you're thoroughly convinced you've got it right.
Otherwise, you might end up taking the drivers out to get at the X-over to make changes.
As you spend time listening to the speakers and listening to various kinds of audible material, you may decide the tweeter is too loud, or the X-over point is too low, or some other process you "hear" that can be improved.
 

·
Registered
Joined
·
205 Posts
Discussion Starter #110
Re: Crossovers

Now what if I wanted to put the xo in base? The feed wires would be 24"- 30". I don't see that a issue, but could I guess.

4 completed boxes/stands, my buddy also has a pair, he's going to see if he can upgrade/tweak them.

He's liking the $29 woofer so far though.


You've got some nice looking units. Well done.
It's useful to keep the X-over outside the box until you're thoroughly convinced you've got it right.
Otherwise, you might end up taking the drivers out to get at the X-over to make changes.
As you spend time listening to the speakers and listening to various kinds of audible material, you may decide the tweeter is too loud, or the X-over point is too low, or some other process you "hear" that can be improved.
 

·
Registered
Joined
·
1,001 Posts
You can put the X-overs in the base or anywhere it's "handy" or "complimentary" or even "artistic" if that's possible.
X-overs don't have any visible moving parts except in the electronic realm so visually they are unexciting. But lately, designer capacitors have been produced that have nice looking exteriors, and even some inductors have been wound on semi fancy spools, but resistors are still ugly. So, I guess if you think maybe a platform of electronic components might look somewhat like "war" equipment or even alien space hardware, I say put them inside somewhere away from little prying hands.
 

·
Registered
Joined
·
205 Posts
Discussion Starter #112
Thanks Island. I may build the xo in the speaker base one day.

Still making these and enjoying them. My buddy has the Prototype boxes; he put new tweeters in them, should be interesting.
 

Attachments

·
Registered
Joined
·
1,001 Posts
I've looked at ALL the great pictures you've posted and I'm still confused about the ports.
I see that the port end that terminates at the side of the box is flared.
Where, inside the box, does the port begin?
What is the dimension of the port at it's beginning, length and width?

What's that "wire screen " looking like stuff in the back corners?

You mentioned "cork" . . . . where does the cork go?

Is there any "stuffing" (polyfill) in the box?

Is the one round dowel the only "brace" on the inside of the box?

Your woofer choice ( Silver Flute ) is probably the best around for the dollar in that size.

The Zaph Audio website has a test of a whole bunch of mid/woofers and a way to toggle between 2 drivers and all the different test characteristics ie: frequency response, cumulative spectral decay vs frequency, harmonic distortion, and actual measured Thiele/Small parameters. It's excellent material to get acquainted with. It gives you a good idea what drivers (tweeters too) are available at what price and what their performance and measured statistics look like.
(Silver Flute) tests are included there also. It tests very well even compared to $250 and up units.
 

·
Registered
Joined
·
205 Posts
Discussion Starter #114
This all started as a "Dr Watson I need you" moment.

Where, inside the box, does the port begin?

At the back, the sound goes to the back and turns 180.

What is the dimension of the port at it's beginning, length and width?

4-1/4" at the back opening the "vent ports" are 3-7/8" width each - total 12" ID.

What's that "wire screen " looking like stuff in the back corners?

Fabric store pin point sheet, keeps wool stuffing where it belongs and out of the 4-1/4" x 9/16" vent (at back).

You mentioned "cork" . . . . where does the cork go?
I add 3" x 3" cork squares on all sides/top/btm; however the inside of the box gets a nice layer of felt.

Is there any "stuffing" (polyfill) in the box?

5.5oz - 5.9oz PE wool

Is the one round dowel the only "brace" on the inside of the box?

No dowel on the last several project, used a cross brace the helps with gluing the front on.

Your woofer choice ( Silver Flute ) is probably the best around for the dollar in that size.

Agreed.

*These are super easy to build! Just need to remember to cut the width of the sides 9/16" smaller than the top/btm, this makes the gap for back of the port.
 

·
Registered
Joined
·
205 Posts
Discussion Starter #117 (Edited)
Not to change the subject but here's a quick read on BSC
http://sound.westhost.com/bafflestep.htm

Not sure I-buy-into-it, they use a sphere vs. "box", I never build boxes unless there is a compelling reason.

A simple rectangle/box will often have a harsh/edgy sound: i.e. echo/resonance; from my experiences angled boxes with felt and cork walls and "smallish" fronts work perfectly.

One other thought; if the round ball speaker was the brass ring of speaker design, they would be 100s of them available.
 

·
Registered
Joined
·
1,001 Posts
I question the need for "baffle step" compensation in a crossover also. What receiver or pre-amp doesn't have a tone control or set of bass and treble controls for adding or SUBTRACTING bass and treble?
My Pioneer receiver has a dozen different ways to shape the frequency response including adding a curve which simulates perfectly a "baffle step" using MCACC. Also my Behringer DEQ 2496 and my Crown XTi 4000 have the capability through GEQ, PEQ, DEQ to create just about ANY response curve one could need.
My challenge has been to flatten the response of the drivers in a two way system and join the two drivers together with a reasonable level of distortion/diffraction, and clarity in a box with the correct/best/least amount of size/space/volume/ and STILL be appealing to the eye.
You seem to have the driver/cabinet/box to your liking and are/were working on the crossovers.
I've got the drivers . . . . . and am working on the crossovers.
I'm still establishing for myself what's needed and helpful, and what's not.
Lots of DIYers insist on a ZOBEL (impedance compensation network). I'm not so sure. The theory seems logical but in applying the theory, there might not be a need if you can pinpoint the Hz of crossover.
Lots of engineers will suggest a notch filter to reduce a peak in the response. However, placing the notch filter into the circuit with a zobel and a 2nd order Likwitz/Riley crossover creates all sorts of additional anomalies.
Some electrical engineers insist you use 2nd order crossovers or even 3rd or 4th order in special circumstances. Then there are others who INSIST on 1st order ONLY for simplicity and less chance for error.
In the end, it's up to the builder what's used to achieve the particular sound that pleases him. That MIGHT NOT be what looks best in the tests or even what might seem counter intuitive.
 

·
Registered
Joined
·
5,771 Posts
Lots of DIYers insist on a ZOBEL (impedance compensation network). I'm not so sure. The theory seems logical but in applying the theory, there might not be a need if you can pinpoint the Hz of crossover.
With modern amplifier design, the need for a Zobel network is practically redundant as they can handle the loads presented to them much better.
On the other hand, the cost of adding it is minimal....
 

·
Registered
Joined
·
1,001 Posts
With modern amplifier design, the need for a Zobel network is practically redundant as they can handle the loads presented to them much better.
On the other hand, the cost of adding it is minimal....
`

The experts I've read about zobel, indicate a need to keep the impedance of the woofer constant by using a zobel while passing through the response curve @ the x-over point. Otherwise the impedance curve is on an upward slope and changing with frequency therefore a specific value for x-over components can't be established.
 
101 - 120 of 157 Posts
Top