I think that providing each driver in the cabinet .zma files (not frd's) would be to mutual satisfaction so that any question anyone may be interested in, could be answered within a simulation, if Mr.Rasmussen has no objection, of course.
Hello again,
A question regarding the MFC and the NRX-2 drivers. I understand that the MFC was a better "electro acoustic" match to the original but discontinued NRX driver. But is there anything to say abut any comparison in sound between the NRX-2 and the MFC?
Anyone?
A question regarding the MFC and the NRX-2 drivers. I understand that the MFC was a better "electro acoustic" match to the original but discontinued NRX driver. But is there anything to say abut any comparison in sound between the NRX-2 and the MFC?
Anyone?
If it was only that simple to do such a comparison.
For a start, the NRX-2 needs a bigger volume that NRX-1 and MFC drivers. For that reason alone the comparison would mean a different box design. Also, the real reason is that NRX-2 has a much heavier cone mass, it has lower sensitivity and higher electrical Q (less damping), which is why it needs a bigger box. The lower sensitivity also means that the Voice Coils runs somewhat warmer (hotter?) and right from Mk1 the idea was that it should run as cool as possible. It also requires more power from the amplifier (wasted as heat).
So is the list long enough for you? 😀
.
Thanks for the quick reply Joe.🙂
I know all the "long list" but interestingely enough the two speakers end up performing almost equally good (at least theoretically) in a ML-TL design (up to 1 kHz). That is because the parameters equal each other in that type of design. So I thought you or anyone else might have tried them IRL side by side to see how they sound, and work up to 2-2,5 kHz with a crossover.
A quick question if it would be acceptable to substitute the 2 x Jantzen P-Core 18mH/20mH 18AWG with 4 x Dayton Audio 10mH 18AWG Iron Core Inductors (DCR 0.78)?
I am having hard time finding a good option for 20mH p-core inductors in the US, but the Dayton Audio iron core chokes are easily available from Parts Express for just $10.98 each. Thank you!
I am having hard time finding a good option for 20mH p-core inductors in the US, but the Dayton Audio iron core chokes are easily available from Parts Express for just $10.98 each. Thank you!
Aa007:
Try Erse (http://www.erseaudio.com). I used their 20mH 16 Gauge inductor in the Elsinores I built to excellent effect (part no. ESQ55-16-20000).
Erst also offers some options for a 300 uF 100V cap you can use at C3; I used their best (part no. ANP10-05-300.0/PB), which was absurdly inexpensive.
Regards,
Scott
Try Erse (http://www.erseaudio.com). I used their 20mH 16 Gauge inductor in the Elsinores I built to excellent effect (part no. ESQ55-16-20000).
Erst also offers some options for a 300 uF 100V cap you can use at C3; I used their best (part no. ANP10-05-300.0/PB), which was absurdly inexpensive.
Regards,
Scott
SRMcGee:
Excellent advice, Scott! And the discounted price on the caps almost covers the shipping costs as an additional bonus.
I also saw your earlier post about using the Ultratouch denim insulation (50mm / 2" thick) sourced from Home Depot, and bonded Dacron (25mm / 1" thick) sourced from Meniscus Audio for internal damping. Did you end up using just Dacron in the front, and a combination of the Ultratouch & Dacron in the back?
I find that the Ultratouch insulation produced quite a bit of dust inside the enclosures in another speaker project I did, but maybe with Dacton on top of it, it will be less prone to sending particles into the air.
Excellent advice, Scott! And the discounted price on the caps almost covers the shipping costs as an additional bonus.
I also saw your earlier post about using the Ultratouch denim insulation (50mm / 2" thick) sourced from Home Depot, and bonded Dacron (25mm / 1" thick) sourced from Meniscus Audio for internal damping. Did you end up using just Dacron in the front, and a combination of the Ultratouch & Dacron in the back?
I find that the Ultratouch insulation produced quite a bit of dust inside the enclosures in another speaker project I did, but maybe with Dacton on top of it, it will be less prone to sending particles into the air.
A quick answer, if that is the option available, then yes. I have done similarly in the past, using 2 x 9mH, but then they no longer became available.
Aa007:
Exactly! The Meniscus-sourced 1" Dacron was used on the sides and on top of the 2" Ultratouch on the rear. I wasn't aware of any dust issues with the Ultratouch; it just happened that we covered the Ultratouch with the Dacron.
Good luck with your build!
Regards,
Scott
Attachments
Thank you for the prompt replies! As I was readying to purchase all the parts, I realizes that the plywood thickness in the US does not quite match up with the required 18mm and 25mm. What is available are 3/4" and 1-1/8" plywood sheets, that translate to 23/32“ (or 18.256mm) and 1-1/8“ (or 28.575mm) in actual thickness. Are these variances acceptable, or will I need to recalculate the cabinet sizes to maintain the total internal volume?
I for one cant say whats allowable, but like yourself had to use material that measured 3/4" for everything. I modeled the Elsinore's in sketchup and when I was done made small changes to keep the volume as close to Joes's design as possible. That meant, I had to first draw Joes design, and measure the volume subtracting all of the internal stuff.. What a PITA, but I could not be more pleased with the results.
That said, attached is my drawing. I take no responsibility for any mistakes. It is what I used. Your free to verify and modify it any way you like...
This is what the thread is for. Down here it is 25mm and 18mm MDF everywhere, but in other parts of the world... but this is the nature DIY. And this is the real reason we have this thread going, now since February 2007, we are nearing 14years anniversary. 🙂
Did you have a ruling, Joe?
IMHO the difference will be superficial, whether you let the error occur inside or outside.. as long as you get everything to fit together.
IMHO the difference will be superficial, whether you let the error occur inside or outside.. as long as you get everything to fit together.
Seems like somewhere on Joe's website and/or this thread there is a internal volume listed. Just can't remember if its after bracing and drivers or before. I calculated it at one point and IIRC it was 79L after bracing (don't take my word for it).
Aim at the same internal volume and front panel dimensions. If any adjustment required to the volume, it is preferable that the depth of the box be varied and leave everything else the same. So, for example, make the box a bit deeper if you loose volume elsewhere.
I think, allowing for bracing, a bit over 70L. But when the fill is in place, it behaves like it is in the 100-100L area. This interacts with the port to give a tuning 33-35 Hertz. Because it has somewhat Bessel characteristics (IMO), it is much less critical (for DIY that is important) than if it was a Butterworth 4th order - and sounds better too.
Subtracting all of the internal bracing, measuring only empty space I came up with 74.93 L (4572.9 Cu In) lol...
Keeping the front panel dims, I must have missed that!!
I for whatever reason wound up just shy at 10.5" or 266.7 mm (in stead of the 280) I now see I kept the side panel spot on... DOH!....
So, Joe... What happens with sound and front panel dimensions getting smaller?
You can round the edges but keep the radius small, best not more than 5mm (10mm diameter) as it reduces the front panel area. If you reduce it too much then the diffraction loss will start a higher frequency and potentially upset the tonal balance. Perhaps making L1 to a smaller value would compensate, but I would not like to see it changed too much. Altering the depth of the box would have a near-zero effect, so that dimension could be used to tweak the volume.
As per usual, this discussion uncovered another interesting point to note, that the roundover router bit radius for the front baffle shall be no more than 1/4" (or R 6.35mm).
If I may, Scott or others in the US, could share what kind of the PVC tube you ended up using for the port?
If I may, Scott or others in the US, could share what kind of the PVC tube you ended up using for the port?
1/4" is only going to be there for looks, due to its size.
You can have a functional roundover if you find the right value of L1. This 2.5 way crossing arrangement is the easiest to work with for tuning the baffle step, even perhaps without measurement.
You can have a functional roundover if you find the right value of L1. This 2.5 way crossing arrangement is the easiest to work with for tuning the baffle step, even perhaps without measurement.