Aurasound/Hi-Vi 2-way for a Noob

[gmcalabria]

I've seen a few people praising the Aurasound NS6-255 drivers, so now that they're on clearance by PE and Madisound, I'm working on a 2-way with the Hi-Vi K1.

The design I've worked up is a budget design as a first full build. I'm using the NS6-255-4A since it's closer to the impedance of the K1, but I may go 8 ohm since this probably won't be used on a hi-fi system. I used Jeff Bagby's crossover designer to give me the response shown as attached. +/-1dB (almost) with a 1st order low pass @750 Hz and an LR2 high pass @3kHz. Sounds too far apart, but the JBagby spreadsheet doesn't seem to think so. I'm also using an L-pad on the tweeter and a zobel circuit on the woofer, all calculated by the same program.

I'll be using a heavily damped .173 cuft enclosure for a 100Hz F3 as picked by Eminence Designer. I've decided to go this way since everyone seems to think that the Aura's weakpoint is heavy, muddy bass, so I'm not going to port the enclosure just to extend that. I'd rather use these as surround speakers.

I'm mostly looking for advise for a first build. I'm not looking to make a hi-fi system, just to show myself that I'm not missing something. @ $50/pair for drivers, I'm not terribly worried, but I'd like some advise before I jump in. I don't know what your guys' experience with Eminence and Bagby's software has been. Any input is welcome.

Thanks guys.

[gmcalabria]

BTW, as far as testing the crossover, I do have a Behringer digital crossover and an old 7.1 channel receiver with direct inputs. I'll be using this equipment to bi- and tri-amp setups to finalize crossover values before I buy componentry.

[Boscoe]

Hi what is that program you used go the crossover?

[gmcalabria]

Jeff Bagby has a few excel-based audio designer programs. I've seen once where it didn't work well (compared to an existing, measured design) and other times when it has done well. I figure if that's what Jeff uses, he seems to be a pretty well experienced/respected speaker builder, so it can't be that bad, but I'm sure (like everything) it has its limitations.

jbagby

I used another baffle diffraction simulator, also a free excel program (can't find it again online) that seems to give similar results to Bagby's, but includes multiple driver support.

[gmcalabria]

Originally Posted by Boscoe

Hi what is that program you used go the crossover?

Did you get a chance to check that out? I'm curious to see what someone else thinks of that program.

[Boscoe]

In all honest I have no clue with it, I only got using it a few days ago because I had to get excel goin.

Sorry I couldn't help with your questions it's just I'm trying to learn more about crossovers too!

[gmcalabria]

Alright, so, I feel like I generally go by John Krutke's design mantras. Seems to be a good idea. One thing I don't understand is BSC. I feel like there are three ways to go about it:

1. Shelve down the upper portion of the woofer's response and design the top half of the woofer response and tweeter to match.
2. Place a second (or third or fourth) woofer with a 1st order low pass at the BSC such that the last woofer makes up exactly for the loss in bass.
3. Just put the speakers against the wall. This is valid, right? I'm not just making this up, am I? If this is bad, tell me why. It seems like some (especially older "NE sound" speakers) are known to need to be next to a wall.

Advice?

[wolf_teeth]

I use it exclusively to do my xovers.

If you had an inaccuracy in your setup relating the project and adapting it's plots, then that is why the PCD sim did not resemble the final output. I've had 3-4 outcomes that were virtually identical to the simulation, so it is end-user error I feel.

Let me know if you require some help...and I have a few blogs here that may be of some help too:
Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com - Wolf



Later,
Wolf

[gmcalabria]

Thanks Wolf. I never got the email that you responded, so now I'm slow responding.

I had a thought here. I've been considering going 2.5 way. I hate the idea of running BSC that burns off power above the BS frequency, so I really like 2.5 way (in theory). I don't know what 2-way speakers that I've heard do and don't run BSC though, but I'm assuming any speaker that sounds best right against the wall doesn't have it (Avid 102, AR M-1).

My understanding of 2.5 way is running another woofer in parallel, crossed using a 1st order @ the BSC to gain 3 dB back,but this will half the impedance in that bass region. I'd rather not run 4 ohms since this is a budget project that will be used on cheap amps.

I had another thought: run 4 ohm Auras and wire the .5 way in series. I won't gain any sensitivity back, so I'll have to pad down the midrange/treble over the BS frequency (88 db/W/m), but I'll gain power handling in the bass region, have an 8 ohm bass region (heavy amp load region), and it'll reduce the stress/excursion/distortion in the bass region. That's my thinking, anyway.

How does this sound to you guys?

BTW, I had a thought that a good way to do BSC in a 3 or 4 way setup would be to use a 1-6 dB more sensitive woofer, crossed over @ the BS frequency. I think this will only work out well if you use a 1st order x-over on the woofer, but it seems like a good idea...

[wolf_teeth]

Originally Posted by gmcalabria

My understanding of 2.5 way is running another woofer in parallel, crossed using a 1st order @ the BSC to gain 3 dB back,but this will half the impedance in that bass region. I'd rather not run 4 ohms since this is a budget project that will be used on cheap amps.

No- you gain full comp of 6dB with just a coil on the cascaded woofer.

I had another thought: run 4 ohm Auras and wire the .5 way in series. I won't gain any sensitivity back, so I'll have to pad down the midrange/treble over the BS frequency (88 db/W/m), but I'll gain power handling in the bass region, have an 8 ohm bass region (heavy amp load region), and it'll reduce the stress/excursion/distortion in the bass region. That's my thinking, anyway.

2.5-way series wiring not possible without a lot more components. Helmuth has a viable alternative see below attached.

BTW, I had a thought that a good way to do BSC in a 3 or 4 way setup would be to use a 1-6 dB more sensitive woofer, crossed over @ the BS frequency. I think this will only work out well if you use a 1st order x-over on the woofer, but it seems like a good idea...

You don't have to use 1st order on the woofer to implement the BSC, in fact that is probably not a good idea to try. Your method will work, just not with a 1st order filter.

Later,
Wolf