15" woofers crossed to BG Neo8, any recommendations?

0 Members and 1 Guest are viewing this topic. Read 8253 times.

JohnR

Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #60 on: 13 Nov 2017, 09:13 am »
I will probably run the woofers in series but still add binding posts to each woofer and then do the series connection via the binding posts. Then I will have the option to change the woofers to 8 ohm drivers in the future, if I wish to do so.

I'm not entirely sure I follow that. I would use temporary wiring rather than bring out every woofer terminal for later wiring. It's OB, it's not like you have to dismantle a box to change wiring :)

On the amp thing, first determine which equipment the noise is from. This does actually expose a potential flaw with active speakers, which is that out-of-band noise is not attenuated (as it is with a passive crossover). If you have a driver with e.g. a large resonant peak at 3-4 kHz, system noise could be magnified by 10-20 dB in the most sensitive hearing range.

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #61 on: 13 Nov 2017, 09:29 am »
I'm not entirely sure I follow that. I would use temporary wiring rather than bring out every woofer terminal for later wiring. It's OB, it's not like you have to dismantle a box to change wiring :)

On the amp thing, first determine which equipment the noise is from. This does actually expose a potential flaw with active speakers, which is that out-of-band noise is not attenuated (as it is with a passive crossover). If you have a driver with e.g. a large resonant peak at 3-4 kHz, system noise could be magnified by 10-20 dB in the most sensitive hearing range.

Well, I plan to run the wiring between the middle and back MDF board and via the leg supporting the MDF boards. Then attach binding post on the leg.
Quick sketch:



I will be able to change wiring but not easily.

The noise is from the amp on all outputs. It's there when nothing is attached but power and a speaker driver. The noise seems identical on both woofer and tweeter with the driver frequency limits taken into account.

matevana

Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #62 on: 13 Nov 2017, 05:43 pm »
The pic you posted looks a little like an infiltration of low voltage DC. If so, this could be a regulator / internal amp repair.

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #63 on: 13 Nov 2017, 07:55 pm »
The pic you posted looks a little like an infiltration of low voltage DC. If so, this could be a regulator / internal amp repair.

I am beginning to realize that it will need a repair. I'm just fearing the cost of it to be honest, as I paid about $610 USD (3900 DKK) for it (used) and wouldn't like to see that figure double.

However, I have asked about repair and price estimate.

If I was just able to do it myself :)

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #64 on: 22 Feb 2018, 06:49 pm »
Long time, no time to build but time to think.

I can't seem to get driver acoustic centering out of my head, which will not work with the current design idea. Therefore, I may be changing my mind. To align centers, the mid and high must be placed above the woofers. However, I do not want a 55 cm stick rising from the woofer baffle containing the Neo 8, 3, 8.

My question is, am I able to place the Neo8's together sideways as done with the Neo10's in the Serenity Acoustics Super-7, to maintain the horizontal and vertical dispersion pattern?

Then place the Neo8's and Neo 3 side by side above the woofers on a separate baffle. This also gives me the opportunity to change the top section, if I someday want to try something else. A bit inspired by Pure Audio Projects approach.

JohnR

Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #65 on: 5 Mar 2018, 10:04 am »
I'm guessing you have the same problem as me, no proper workshop. Therefore, more "thinking time" than "building time"... :(

I think you are starting to get analysis paralysis. (I have a vague idea I said this already in this thread... oh I looked, I did!) If you position the way you say then you will have compromises in off-axis rseponse. However you don't know how audible it is, and at the same time you are juggling aesthetic considerations. I don't think anybody can get it right the first time anyway, so perhaps decide which is important, then "build one to throw away" and just see what it sounds like / if it sounds good enough to you. (My friends laugh at my constructions with sticks and pipe cleaners but it means I can try something in an evening or two.)

 :thumb:

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #66 on: 5 Mar 2018, 10:57 am »
Yes, analysis paralysis you already have mentioned - and you are right  :D

Well, I know it's the right way to go to test-build, but when I'm this slow at even building something, I find it difficult to prioritize test builds. Instead, I have analyzed  :oops: that I want to make a living room friendly customizable design. That means a dual 15" woofer section that can accommodate various 15" woofers, for example various woofers from Eminence and Acoustic Elegance with little or no modification - mounting from behind, same fabric front cover etc.
And a fabric top cover covering mid/high, which let me edit/change that configuration without it being visible. That allows me to use separate baffles, acoustic felt etc. that normally fail WAF.

Somthing like this:


Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #67 on: 28 Jun 2018, 02:17 pm »
Analysis paralysis still present.

Neo8 has been skipped and I'll go for a 5" midrange instead. Couldn't make design and acoustics align with the Neo 8.

Any alarms ringing with the design below?





My main worry is the top section. Will it have significant negative influence on midrange and tweeter?

Thanks for any replies!

FullRangeMan

  • Volunteer
  • Posts: 10534
  • All Tweeters look like a target, then shoot them!
    • Never go to a psychiatrist, adopt a straycat or dog. On the street they live only two years average.
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #68 on: 28 Jun 2018, 03:49 pm »

The botton woofer is too hi from the floor.
The other image schema is better for bass freq.

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #69 on: 28 Jun 2018, 05:34 pm »

The botton woofer is too hi from the floor.
The other image schema is better for bass freq.

Not sure I follow, sorry. I can't see how I can get the lower woofer any closer to the floor.

The two images are of the same speaker with and without grills from front and back. Should have explained that to begin with :)

FullRangeMan

  • Volunteer
  • Posts: 10534
  • All Tweeters look like a target, then shoot them!
    • Never go to a psychiatrist, adopt a straycat or dog. On the street they live only two years average.
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #70 on: 28 Jun 2018, 11:09 pm »
You are correct, disregard my post :thumb:
It was a mirage due the biding post wall.

MJK

  • Full Member
  • Posts: 458
    • Quarter Wavelength Loudspeaker Design
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #71 on: 28 Jun 2018, 11:39 pm »
Extend the mid and tweeter baffle to fill the entire area and then offset the two drivers so they are not symmetrically mounted. Add some fiber behind the mid and tweeter or trim away the sides and top to eliminate the cavity.

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #72 on: 29 Jun 2018, 06:56 am »
Extend the mid and tweeter baffle to fill the entire area and then offset the two drivers so they are not symmetrically mounted. Add some fiber behind the mid and tweeter or trim away the sides and top to eliminate the cavity.

Thank you for your answer.

As I've been reading here and on other forums for a while, there seems to be two camps regarding narrow vs. wide baffle. As I don't want to trim away sides and top due to aesthetics, the wider baffle may be the better option for a more controlled forward radiation, if the reflections from sides and top will interfere. Fiber will be applied to the cavity either way.





Also, as I plan to use grills front and back, I can make it as WAF unfriendly as needed. Measurements will probably tell the most, but as I'm not planning to round the edges of the cabinet (aesthetics and planning wood veneer (first time)), will applying damping material on mid and tweeter baffle help me out?

Any better solutions?

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #73 on: 5 Jul 2018, 12:41 pm »
Another question regarding offsetting the drivers. From what I know, you do this to spread out baffle diffraction and to even out the dipole cancellation, but won't this result in uneven off-axis response (left/right) having uneven distances to the sides?
I tend to have learned that even off-axis response is almost as important as an even on-axis response, and that it's very difficult to DSP/crossover you way out of. Whereas it's easier to even out the frequency response when it comes to baffle diffraction. Although the combined frequency response doesn't tell the source - the edge %-contribute will be about the same not doing anything positive.

So, will center placement + felt on front baffle be the best case? Even left/right off-axis + damping of baffle/edge contribution, but a more concentrated edge contribution.
Or will offset +  felt be the better compromise? Slightly uneven left/right off-axis + damping, but dipole cancellation and diffraction smoothed out.

JohnR

Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #74 on: 5 Jul 2018, 03:45 pm »
Use Edge and put a small driver in the center of a wide baffle, you'll see why you shouldn't do that. I wouldn't have thought felt would fix it but I'd be interested to see measurements that show otherwise - if you have a link to any?

So either offset the drivers or make the baffle narrow. If it were me I'd use the small baffle in your earlier rendering but remove the frame around it. In either case try a simple simulation with Edge.

AJinFLA

  • Industry Participant
  • Posts: 1017
  • Soundfield Audio Loudspeakers
    • Soundfield Audio
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #75 on: 5 Jul 2018, 07:35 pm »
Any alarms ringing with the design below?

No. Keeping the baffle around drivers narrow is good for off axis...and thus what you hear. Your fabric cover top example above that, better yet.

If it were me I'd use the small baffle in your earlier rendering but remove the frame around it.
Agree. Would possible see if the "frame" could be turned into grill/cloth/acoustically transparent if wanting to maintain that rounded shape.

cheers,

AJ

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #76 on: 6 Jul 2018, 07:07 am »
I did "develop" the design with top frame a little further, but I wanted it to become more living room friendly. No visible drivers and appear more simple and shallow.


If I were to combine the designs it would something like this.


I just like the wooden frame, as I believe it results in a simpler design. But I my be able to get the above working, if it's the absolute best solution. Wide or narrow baffle.

JohnR

Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #77 on: 8 Jul 2018, 05:32 am »
Maybe you can make it so that the top piece holding the midrange and tweeter is removable. Then you can measure different baffles :)

Fjendbo

  • Jr. Member
  • Posts: 52
Re: 15" woofers crossed to BG Neo8, any recommendations?
« Reply #78 on: 8 Jul 2018, 08:10 pm »
Maybe you can make it so that the top piece holding the midrange and tweeter is removable. Then you can measure different baffles :)

I will not have fixed baffles for the woofers or top section, so drivers and baffles can be swapped :)