2 midrange panels!
Also got some clear acrylic 18mm cut for 6 x 15" woofer. Was going to use 15PR400 but was easier and cheaper to get deltalite 2515. Will have to live with the slightly higher FS. The eminence and B&C/Faital woofers have different screw hole ring diameters so made the holes bigger and shot for the middle. Might have to sand the edges to clean up the fog but I depends how lazy I get.
Waiting for the 2515 drivers to arrive. Might be a while. On to the wiring harnesses.
Also got some clear acrylic 18mm cut for 6 x 15" woofer. Was going to use 15PR400 but was easier and cheaper to get deltalite 2515. Will have to live with the slightly higher FS. The eminence and B&C/Faital woofers have different screw hole ring diameters so made the holes bigger and shot for the middle. Might have to sand the edges to clean up the fog but I depends how lazy I get.
Waiting for the 2515 drivers to arrive. Might be a while. On to the wiring harnesses.
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No not mine, just came across it on Parts Express when looking at the ribbon you used. Seems well built, I'm not sure the aluminium plate in front of the full range is a benefit. I have seen someone use a plastic tube in front of an array before as a sort of phase plug, didn't seem to affect it too much so I thought the ribbons embedded in half a dowel or something similar might work.
If I was to build another dipole I would not make the tweeter dipole by using two tweeters back to back. It highlighted flaws in some recordings that became hard to un-hear. A bigger distance to walls may have helped, but I noticed no benefit from having it dipole over the full range.
Ya I was wondering if the aluminum shape on the PE build was some sort of phase plug (would have been a prime candidate) but it really looked like just a mounting bracket.
Good idea, a half dowel would probably work. It would be interesting to see some measurements of the build you mentioned. I think it would work really well. If I were to do a sealed LA again I'd probably go that route and use slightly larger midrange drivers. The PT mini are really a cool little driver for that kind of application, plus I would enjoy the look.
Currently the tweeter array is not dipole. Will do some subjective listening when they are up and running before going that extra distance. Seems like it would be of little benefit up there but my ocd might say do it for completeness. If not it might be worth it to finish the rear of the tweeter array like you suggested and test it with the SB build. It's only time lol.
Good idea, a half dowel would probably work. It would be interesting to see some measurements of the build you mentioned. I think it would work really well. If I were to do a sealed LA again I'd probably go that route and use slightly larger midrange drivers. The PT mini are really a cool little driver for that kind of application, plus I would enjoy the look.
Currently the tweeter array is not dipole. Will do some subjective listening when they are up and running before going that extra distance. Seems like it would be of little benefit up there but my ocd might say do it for completeness. If not it might be worth it to finish the rear of the tweeter array like you suggested and test it with the SB build. It's only time lol.
Was hoping to get some better measurements but this is tough in the position they are located in. Looks like measurements are only good till 700hz gated but will be taking some smoothed measurements later.
Midrange panel only. Blue is on axis about 12" from driver and halfway from floor to ceiling. Green is roughly 45 degrees and Red is 90 degrees. Maybe cross to the tweeter array at 7khz.
Also tweeter array at the same distance and degrees. This is non-dipole tweeter config.
Midrange panel only. Blue is on axis about 12" from driver and halfway from floor to ceiling. Green is roughly 45 degrees and Red is 90 degrees. Maybe cross to the tweeter array at 7khz.
Also tweeter array at the same distance and degrees. This is non-dipole tweeter config.
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You can easily use 4ms gating, but there will be some dips from reflections.
Looks like dipole pattern goes up to 2khz. Progressive directivity from 7kHz up. This means that in a room (with sidewalls) you'll get too much sound energy and poor CSD between 2 - 7khz, at listening spot.
Really interesting to me is to see how response changes with distance. Line arrays were invented for wide open spaces (PA use) when scattered interferences smooth the sound power through spectrum. Quite contrary to domestic hifi goal towards point source "coherence" with lots of direct sound. A dipole radiator in a room is also controversial...
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Does it change with distance or angle, I don't see a distance change within these measurements...
Expecting to see those too later on...
Domestic listening distance is in nearfield of a 2,5m high line array.
Speaker off axis: constant beamwidth transducers (CBTs) - Acoustic Frontiers
https://stevebunting.com/downloads/linearrays.pdf
FUNDAMENTAL LIMITATIONS OF LOUDSPEAKER DIRECTIVITY
Oh no, not the CBT graphs again, in here we talk about floor to ceiling arrays, not truncated arrays.
Infinite Line Source: analysis
So throw away those truncated array simulations as they do not apply.
Infinite Line Source: analysis
So throw away those truncated array simulations as they do not apply.
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Hi Juhazi,
Out of interest, with the Aino what dipole response frequency did you get to with just the neo8-pdr on your baffle? I expect to get the same response horizontally as these should be similar, unless something else is going on.
My room is more damped than the average room as I use it for multichannel as well as stereo and multichannel required much more damping. I found without it there was a lot of problems with opposite walls. That said it is still not enough passive treatment as I didn't want to go completely overboard and destroy 2ch. A compromise for both might end up being the worst case for everything though.
I'll take some more sweeps at a later date. The speaker is only 66% complete and I need to spend much more time with it before getting further.
I expect off axis issues (as it's like listening to a speaker turned on its side) and a whole host of crappy measurements but I wanted to see how far I could push this build. Worst case is I end up with a large, wide baffle that doesn't hold dipole pattern that well. I'm hoping some spacing between lines will allow at least some cancellation at the sides but you can't beat physics.
Also measurements are going to be hand wavey as the baffles are fixed to the only position allowed and I can't move them around for proper measurements. There will be some reflections in most of the sweeps, that will be unavoidable.
I'm certain it doesn't measure great and WILL change with distance and angle as it is in a crappy room, but I'll take the ugly sweeps for show after all the baffles are up and running. There will be limitations with measurements.
Was looking at charlies thread on dipole response up to 20k. I don't expect to get that high and as long as it sounds subjectively good warts and all, I'll be happy.
Also the degrees/angles are not well defined, I don't have a protractor out so they won't be spot on. My setup right now only allows for a USB mic as my computer and other gear are in a different room. I might have to get something better up and running for this project though.
? Some huge Line Arrays?Oh ya, forgot to say one of the goals of this project is a radically different power response than my 2 way Horns. Going from a front pattern controlled point source to a Line Array dipole is pretty far apart from each other.
I see where your response drops at about 5db/oct below the dipole peak. At a distance of 12" you wont be seeing but a partial line array. As distance increases you will picking up the radiation from all drivers in the vertical, you will notice the response dropping closer to 3db/oct from the dipole peak. 
I see where your response drops at about 5db/oct below the dipole peak. At a distance of 12" you wont be seeing but a partial line array. As distance increases you will picking up the radiation from all drivers in the vertical, you will notice the response dropping closer to 3db/oct from the dipole peak.
Yes, I'll try and post some of the distance sweeps shortly.
Only Midrange panel shown
The idea was to have some space between panels. Because the Bass array is not finished, I used my existing SB Line array (sealed) for the woofer array. Because of the SB line array base, I have roughly 6 inches between midrange panel and the SB lineArray. This translates to a hard surface roughly 12" in length along the side of the midrange panel.
Mic is 3" from driver on axis and 3 " from panel at 90 degrees. Smoothed 1/6 and gated. While not indicative of the final array, I wanted to see the damage done.
The idea was to have some space between panels. Because the Bass array is not finished, I used my existing SB Line array (sealed) for the woofer array. Because of the SB line array base, I have roughly 6 inches between midrange panel and the SB lineArray. This translates to a hard surface roughly 12" in length along the side of the midrange panel.
Mic is 3" from driver on axis and 3 " from panel at 90 degrees. Smoothed 1/6 and gated. While not indicative of the final array, I wanted to see the damage done.
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Looks like it's going to be a little while till I get the bass array finished.
Had a quote from Q components in Canada and put in a credit card order for some Eminence 2515 deltalites.
Really wanted to support a Canadian company but today recieved an email saying they were going to charge me a minimum of 10% on my order due to exchange rates. It is unfortunate but I can't eat the total+ cost after being quoted and ordered several weeks ago so I had to cancel my order.
Will probably use parts express exclusively for my b&c and eminence orders from on. A shame.....
Had a quote from Q components in Canada and put in a credit card order for some Eminence 2515 deltalites.
Really wanted to support a Canadian company but today recieved an email saying they were going to charge me a minimum of 10% on my order due to exchange rates. It is unfortunate but I can't eat the total+ cost after being quoted and ordered several weeks ago so I had to cancel my order.
Will probably use parts express exclusively for my b&c and eminence orders from on. A shame.....
Don't think buying from Parts Express directly will help. VISA will charge you the going exchange rate, and as the USD is the currency of choice during crises, the CA$ has plummeted against USD: CA$1=USD1.46 today. That's at least 10% worse than 2 weeks ago. Me, I putting all my audio purchased on hold for now.
With discount, shipping and import tax it still works out cheaper for me at PE than Q components with the current exhange rate.
What bothers me is I was given a quote and gave them a credit card for ordering and they changed the terms of the deal weeks later saying we'll add at least 10% on your purchase, sorry for the bad news. Didn't ask if I was ok that or not, but assumed an open ended bill to charge what they saw fit. Sorry, I don't do open ended bills on credit card.
It is more the way it was done, so all else being equal I would have liked to stay Canadian but not really liking the terms.
In all I can see how this happened as they probably have terms with Eminence so they ordered on credit and the $ tanked. I guess I should be happy that they gave me such a good price that the change in exchange rate would not have made them $$$ and they are not a charity but they could have handled it better in my opinion.
What bothers me is I was given a quote and gave them a credit card for ordering and they changed the terms of the deal weeks later saying we'll add at least 10% on your purchase, sorry for the bad news. Didn't ask if I was ok that or not, but assumed an open ended bill to charge what they saw fit. Sorry, I don't do open ended bills on credit card.
It is more the way it was done, so all else being equal I would have liked to stay Canadian but not really liking the terms.
In all I can see how this happened as they probably have terms with Eminence so they ordered on credit and the $ tanked. I guess I should be happy that they gave me such a good price that the change in exchange rate would not have made them $$$ and they are not a charity but they could have handled it better in my opinion.