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Multi-Way Conventional loudspeakers with crossovers

Fast, fun, Inexpensive OB project
Fast, fun, Inexpensive OB project
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Old 30th October 2017, 08:45 PM   #1621
B00B00 is offline B00B00  Canada
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Quote:
Originally Posted by Pano View Post
In general, Open Baffle doesn't have the impact that box speakers do, unless you get to very large baffles and woofer surface area. It's a different sound. But playing around with the distance to the wall can make a difference in how much mid-bass you hear. If you can, within the limitations of your room, try different distances to the wall behind


Thanks Pano, the tricky part is that I have no wall behind. I have a central fireplace that divides the living room from the dining room and a hallway on both sides. The speakers are in the hallway so to say. That being said, I think it's a preamp issue. My preamp recently died and so I pressed my Cambridge integrated into service as a pre. It simply doesn't have enough gain and feels like a wet blanket has been thrown over everything. I have since swapped in a Yamaha ax700u and an Nad 7240 into the mix and it is muuuuuuch better.

Last edited by B00B00; 30th October 2017 at 08:49 PM.
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Old 30th October 2017, 09:37 PM   #1622
John Busch is offline John Busch  United States
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Default Pesky inductors

I used the 14 Ga. because I use those as a standard, and with the inductor in series with the mid-tweet inductor wire size and resistance does mater. It has been my experience that the inductor is usually with weakest component in a good passive crossover. Caps you can bypass. I can hear the difference between and 18 ga. and a 14 and a 12 and so on. Most pronounced in the lower mid range. Clarity... minimal ringing. Play some well recorded piano and it will show you in a hurry, even with a simple low cost design like the Manzi. Don't get the wrong idea, the 18 is not bad, just the larger ga. is better. Once you get larger that 14, the cost sky rockets.
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Old 2nd December 2017, 09:59 AM   #1623
pieter1008 is offline pieter1008  Belgium
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Hi,

I am going to build the Manzanita (regular one on stands) with the GRS woofer. I have the drivers, the crossover components are on their way. I am from Belgium and shipping was expensive from parts-express so I ordered 4 GRS woofers and 4 TC9's so I can build 2 pairs of speakers, after I build the small manzanita and if I like it I will build the Ultra. I was about to order the inductors also from parts-express but they were a lot cheaper to buy in europe (maybe copper is cheaper in europe?).

I now have to decide what wood I am going to use, in this case with open baffle the baffle material is most important I suppose.
I am thinking about high quality pine plywood, baltic birch plywood (expensive) or solid pine/spruce/oak furniture panel. Are there big sonic differences between these materials or is it subtle differences?
The baffle thickness is advised 0.7" minimum, is there an advantage to having a 1" or 1.4" thick baffle? I was thinking about glueing 2 panels together for the baffle to increase thickness?

Pieter
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Old 2nd December 2017, 05:28 PM   #1624
John Busch is offline John Busch  United States
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Hello Pieter...

Thank you for your interest in the Manzanita and Ultra! There is a lot of flexibility in construction materials as long as all joints are secure and rattle - buzz free.

.75" is all that is needed for either speaker. Too much thickness can be an issue, especially with the Vifa. The amount of depth behind the Vifa can restrict and reflect the rear output radiation. Not good. I think your best approach to the wood you use will be driven by your cosmetic priorities. For example, for something simple with a painted or glue on veneer surfaces, 3/4" MDF works fine. If you want more of furniture appearance you could use any solid wood, or layers of same to get to the .75" thickness.

The nice thing about the 15" is that it has enough surface area that medium 2-5 MM excursions are sufficient for most bass requirements and that amount of movement is easily handled with .75" baffle thickness.

Please let us know how your project evolves and good luck!

Best
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Old 3rd December 2017, 10:21 PM   #1625
pieter1008 is offline pieter1008  Belgium
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Thanks for the information, it is clear now for me.

I will post once I start assembling them.
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Old 4th December 2017, 09:55 AM   #1626
twocents is offline twocents  South Africa
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Fast, fun, Inexpensive OB project
Default Inductors

Quote:
Originally Posted by pieter1008 View Post
I was about to order the inductors also from parts-express but they were a lot cheaper to buy in europe (maybe copper is cheaper in europe?).
Pieter, I will watch your build with great interest. I have been drooling over this thread for a while now and I am also planning to build the standard Manzanitas next year, if possible. I already have the TC9FD drivers and also access to the GRS woofers, and even other woofers very similar to the GRS.

My biggest hurdle will be the inductors. Cannot find them locally - even if copper is probably the cheapest here in Africa. So with the help of another forum member I started looking into winding them myself. But I don't have access to an oscilloscope - so making and measuring the inductors accurately is a problem and another diy project on its own.

Can you point me to the cheaper supplier in Europe please? In the end I would prefer to get the real deal inductors.
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Old 4th December 2017, 01:41 PM   #1627
lowmass is offline lowmass  United States
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Im a little confused here. The tweeter has been changed to a unit that can go much lower than the original dome, yet using the same basic crossover? Do I have that right?

The reason I ask is a desire to try this arraignment with a crossover around 500hz. Will the woofers response work well with a handoff in this area or is the natural rolloff of the woofer figured into original design using a handoff more around 1500hz??

And BTW what thinkest thow bout this woofer..is the Qt too low??
https://www.parts-express.com/pedocs...ifications.pdf

Thought is it may have a bit better resolution than the paper types above 500 hz?

Last edited by lowmass; 4th December 2017 at 01:56 PM.
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Old 4th December 2017, 02:31 PM   #1628
John Busch is offline John Busch  United States
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The original Manzanita using the Seas TDFC was intended for near field listening in smaller rooms at modest levels for as low a build cost as practical. However, there were some compromises to do that. One was a broad dip in the upper mid-range and second was the limited clean out put. The result was a laid back, but detail response that provided solid bass to 40 Hz.

The next evolution used the Scan Speak D3806 (1.5") mid - tweet that proved to be a major improvement. However the cost of this driver, already pretty expensive at $70 each more than double in a years time. Minimal crossover change was required as the added output of the D3806 just help fill in the lower mid-range.

The Vifa T9 replaced the D3806 at a much lower cost of around $12 each and has proven to be the best match for either the Peerless 12" or the GRS 15". Again, crossover changes are minimal, but the Vifa can benefit from a trap to flatten out the upper treble.

As for the PE Aluminum 12". It can be made to work, but with it's low QTS, limited volume of displacement and relatively high cost it can't compete with the GRS. It may offer a bit more resolution in the 400 - 1,200 Hz range, but can't out do the little Vifa. Plus you are trying to get aluminum and paper to speak with the same voice.

Bottom line, is you would need to do some not so easy crossover work to get the Aluminum 12 and the Vifa to sing. Hope this all make sense.
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Old 4th December 2017, 02:55 PM   #1629
lowmass is offline lowmass  United States
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"As for the PE Aluminum 12". It can be made to work, but with it's low QTS, limited volume of displacement and relatively high cost it can't compete with the GRS. It may offer a bit more resolution in the 400 - 1,200 Hz range, but can't out do the little Vifa. Plus you are trying to get aluminum and paper to speak with the same voice. "

I hear ya. My intention was to build a simple dipole with a ribbon I have that can get to 500 hz. I have played with this in past but didnt spend enough time in design/test to get it all worked out. What I do remember was I came away with idea that the range 500-1.5k on the woofer just didnt match the ribbon well and that the Qts was an issue with the woofer I was using. Bass seemed weak.

Perhaps asking for a woofer large enough to do the bass well BUT hand off to the ribbon may be a real problem??
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Old 4th December 2017, 03:03 PM   #1630
John Busch is offline John Busch  United States
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Finding a ribbon that will play flat to 400-500 Hz and handle a decent amount of power for a reasonable amount of money is difficult. And then there is the voice matching issue. You can try to blend the two, but that takes a good 2 to 3 octave overlap. Not easy with a larger woofer with respectable Xmax and high QTS. Again, not that it can't be done, but will take a lot of work and moola to get it right. Not trying to discourage you, but a two way OB that sings is not easy.
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