Calling all DIY rear channel designs!

[zzzz]

As the title implies, I would be very interested in seeing some examples of highly recommended DIY rear channel speaker designs. I know madisound have an audax kit.

My subwoofer project is winding down, and as the speaker comes together I'm getting an urge to get started researching something new.

I can find no mention of any rear channel designs on the web. I don't know if this means I can use a small monitor style speaker or bookshelf?

The rear channel budget is minimal - $200 for all parts excluding tools, mdf, screws, glue etc.

Many thanks!

[Jed]

I'll have one done in the coming weeks. Should be less than $200 for the Lineup 4D design.

[zzzz]

I'll have one done in the coming weeks. Should be less than $200 for the Lineup 4D design.

Thanks Jed. Not sure what the lineup 4d design is, but I look forward to seeing it!

[Jed]

Thanks Jed. Not sure what the lineup 4d design is, but I look forward to seeing it!

https://www.htguide.com/forum/showpost.php?p=353979&postcount=333

The Lineup series will include the Tangband W4 Titanium, Vifa D26 or Fountek CD3.0, and a fullrange driver. Should have a speaker for everyone looking for a slim and inexpensive design. The MT and MTM will be designed to include a crossover for near wall placement.

[Quwiksilver]

Perhaps this is a good place to plug Zaph's new design?

http://www.zaphaudio.com/ZBM4.html

Seems like the small drivers and close spacing make for nice, wide dispersion characteristics. This would seem to make them ideal for surrounds, no? Also, they're well within your budget.

Scott

[Jed]

Perhaps this is a good place to plug Zaph's new design?

Depends if he wants to mount them on a wall. This is what Zaph said on his website:

The real problem with speakers this small is that people will be tempted to mount them on a wall or place them on a bookshelf or end table. Yes, that is possible, and the alternative reduced BSC crossover version will probably work better in that case. Just be aware that it is non-optimal and early reflections from nearby boundaries or objects will take a serious bite out of the sound quality. If that's your only placement option, then go for it. Just realize that the speakers are not sounding as good as they could be. This will be true for any speaker placed near a boundary or object.

[zzzz]

Perhaps this is a good place to plug Zaph's new design?

http://www.zaphaudio.com/ZBM4.html

Seems like the small drivers and close spacing make for nice, wide dispersion characteristics. This would seem to make them ideal for surrounds, no? Also, they're well within your budget.

Scott

Thanks Scott!

I have never put a cross-over together, but I think this design looks OK for a beginners cross over.

[zzzz]

Depends if he wants to mount them on a wall. This is what Zaph said on his website:

They'll be going into a bookshelf behind our couch. There's a window flanked by two bookcases reight behind the couch. The mega-subwoofer I'm finishing is going into the gap between the bookcases, and the rear channels into the book cases.

Hmmmm... may put them on top of the sub... right at ear level, but reflections off the top of the sub may be problematic. At least in the bookcases I can have them protruding over the edge of the shelf to avoid that issue. They'd also be at ear level.

[kgveteran]

My take on a great design

Here is a modified version of Mark K's twoway. They are very dynamic.They blend perfect due to the RS28a that is in the rest of my system.Feel free to ask any questions.

I've run them through the usual torture tests like U571 and WOTW, the first 20min of Saving Private Ryan.Very dynamic.

KG

https://www.htguide.com/forum/showthread.php?t=23335&page=1&pp=35

Side note: My mains (LCR) are the RS WTMW in my avatar

[Landroval]

As the title implies, I would be very interested in seeing some examples of highly recommended DIY rear channel speaker designs.

It depends a lot on your fronts. Might want to keep similar sound in all the channels. E.g. if you have Dayton RS fronts, better stay with Dayton RS surrounds as well. Better even if all the speakers are identical.

[69Stingray]

First, why don't we discuss what the requirments for rear channel speaker should be. I assume we are talking surround speakers in a 5.1 setup?

- What freq. range is typical sent to the rear channels?
- Does the surround software filter out some sound, like vocies?
- What is the purpose of rear channels?

[sprint_9]

There is an RS150 MT in the Missions Accomplished section that would work well.

[morbo]

Timely discussion as I am in the middle of planning out the rear 4 channels of my own small room home theater as well.

As I understand it, the rear surround speakers (as distinct from the side surround speakers) should be:

• monopoles

• highpassed somewhere in the 80-150hz range by a processor of some sort

• if they are to be on-wall/near-wall, the crossover needs to be designed with that in mind.

The biggest problem I see is the requirement for different crossover in such a speaker, limits you to far fewer choices as few designers make a near-boundary version of their design, since its not really considered a good way to listen to quality speakers. Many people seem to want to ignore the last point, but it is extremely important, and the main reason why so few of the dozens of bookshelf sized speakers can't be used as-is.

Options that I am aware of:

Zaph's has two speakers with on/near wall placement variants:

http://www.zaphaudio.com/ZBM4.html

http://www.zaphaudio.com/audio-speaker20a.html

and of course there are the Modula and Natalie P On-Walls:

https://www.htguide.com/forum/showthread.php?t=22625

https://www.htguide.com/forum/showthread.php?t=22626

Jed's upcoming series will have near-boundary placement crossovers:

https://www.htguide.com/forum/showthread.php?t=26939

That's all that I'm aware of at the moment. Feel free to add to this and I'll update the list, as much for my own decision making process as other's edification.

[Landroval]

As I understand it, the rear surround speakers (as distinct from the side surround speakers) should be:

• highpassed somewhere in the 80-150hz range by a processor of some sort

I don't see the point for that. Both movies and multichannel music use 5-7 fullrange channels so highpassing the surrounds is in a way taking you back to ProLogic times. A good surround speaker goes so low that it can be set 'large' and crossed over to a sub as low as the mains.

[Geoff Gunnell]

If you want to use a global x-o no higher than 60Hz and you want mutidirectional surround/rear speakers to reduce localization, I'm unaware of any cost effective solutions other than custom design. A pair of small bookshelves aimed 45 to 90 degrees apart could conceivably emulate a bipole satisfactorily, but almost all such speakers have actual impedance minimums too low to wire in parallel.

The new HDS tweeter and woofers from Peerless have high enough impedances to wire pairs together to make, say, a 90 degree (included angle) bipole -- even the smaller HDS woofers in a front ported enclosure could easily get down to 60Hz.

[kgveteran]

These are a shortened down version that is wall mounted and really needs no EQ to the original XO design.I use 100hz as the system XO. They run about 200.00 apiece with cabinets made at a local shop for me.

[morbo]

I don't see the point for that. Both movies and multichannel music use 5-7 fullrange channels so highpassing the surrounds is in a way taking you back to ProLogic times. A good surround speaker goes so low that it can be set 'large' and crossed over to a sub as low as the mains.

I don't think the bass management works quite the way you think it does... any speaker set to large receives a fullrange signal, and is not 'crossed over to the sub' in any sense. The sub recieves the LFE channel, and any bass redirected to it from speakers set to 'small'.

Personally I would never set any speaker to large unless it was a true fullrange speaker with significant bass capability to 20hz. For example I have Modula MTs as my fronts, setting them to large will risk overdriving them into distortion or bottoming out frequently, not to mention missing out on any low bass content outside their range that may be sent to the front L/R channels.

[zzzz]

Perhaps this is a good place to plug Zaph's new design?

http://www.zaphaudio.com/ZBM4.html

Seems like the small drivers and close spacing make for nice, wide dispersion characteristics. This would seem to make them ideal for surrounds, no? Also, they're well within your budget.

Scott

How did he get the finish on the design in the above url???? I would love to emulate it on the sub I am close to finishing.

[littlesaint]

If you want to use a global x-o no higher than 60Hz and you want mutidirectional surround/rear speakers to reduce localization, I'm unaware of any cost effective solutions other than custom design. A pair of small bookshelves aimed 45 to 90 degrees apart could conceivably emulate a bipole satisfactorily, but almost all such speakers have actual impedance minimums too low to wire in parallel.

The new HDS tweeter and woofers from Peerless have high enough impedances to wire pairs together to make, say, a 90 degree (included angle) bipole -- even the smaller HDS woofers in a front ported enclosure could easily get down to 60Hz.

60Hz is a good crossover provided the speakers are flat to that low of a frequency. 80Hz is OK, but the crossover isn't a brickwall, so you still get localized frequencies sent to the sub. However, dipole/bipole aren't necessary and possibly a bad idea.. Studio masters are mixed with monopole speakers in 5.1/6.1 arrangement. Plus, if you are going to be listening to multichannel music you absolutely do not want dispersion in the side/rear channels.

[---k---]

How did he get the finish on the design in the above url???? I would love to emulate it on the sub I am close to finishing.

veneer on an mdf box. His Design Mantra's page says that he uses Rustolum Texture Spray Paint for the baffles.

[Geoff Gunnell]

60Hz is a good crossover provided the speakers are flat to that low of a frequency. 80Hz is OK, but the crossover isn't a brickwall, so you still get localized frequencies sent to the sub. However, dipole/bipole aren't necessary and possibly a bad idea.. Studio masters are mixed with monopole speakers in 5.1/6.1 arrangement. Plus, if you are going to be listening to multichannel music you absolutely do not want dispersion in the side/rear channels.

Your comments about x-o slopes and localization is right on. That's part of the problem -- 80Hz with typical equipment is not low enough to avoid localization, especially if the sub has to be placed away from the mains.

SQ is the other issue here -- surround speakers that will play below 80Hz are preferred by listeners -- a guy from Down Under had some interesting data on this at AVS.

And it's the surround speakers that usually limit the sub x-o to 80Hz or higher.

As far as dipole/bipoles not being a good idea, many folks prefer the more spacious sound. Remember we are talking about residential rooms here, often with very short listener to speaker distances. I was reading a review of a switchable dipole/bipole, the reviewer had too much localization in bipole mode and had to switch to dipole mode.

Unfortunately although most studios do now use direct radiators, that does not address the very sloppy mixing that is often done, with a sound suddenly 'sent' to a rear channel -- this is distracting when played back through direct radiators. Many recent titles I buy are still mixed like this.
And you still have to deal with the proximity effects in the listening room.
And you still have to deal with all the older software out there.

[kgveteran]

There is a alot of theory about localizing sound coming from subwoofer.The only time I can hear it is if I turn off all the amps and run the sub alone.Once I turn on all the amps the localization is a moot point.I use 100hz for a global XO point.

Full range mains and surrounds would be nice.I'm sure most don't have room in their rooms or their budgets.A simple alternative is a very capable subwoofer system that can handle the duties of the LFE channel along with the rolled over bass from all seven channels (given you are using a 7.1 system).Then the size of the mains are smaller and so is their budget.With the bass duties removed they have an easier time reproducing frequencies above 100hz or 80hz, what ever your system is XO at.

Many theories are true, but you have to experiment to see is they effect you and your system.Example would be my on-wall surround speaker.I did some sweeps using TrueRta and there is a slight rise around 200hz, about 1.5-3db . There is no way I can hear that and wouldn't bother to EQ it out or redesign a great XO that Mark K did.Like I say theory is fine, always see if it effects you before you treat it as a road block of sorts.

Another example would be the rainbows in a single chip DPL display. However small or large they are there.If you can't see them or they don't bother you then DLP is another viable option.

Experiment,experiment,experiment then use what works for you !!!



KG

[zzzz]

veneer on an mdf box. His Design Mantra's page says that he uses Rustolum Texture Spray Paint for the baffles.

Ah... all is revealed. Thanks Ryan.