Bedroom speaker build (with renders and questions...)

[chirpie]

Hello all, first time poster here. (ulp...)

I had posted this question over at AVS Forum (my usual hangout), but found this forum which seemed far more appropriate. (and active for the DIY crowd)

Hello all! I've finally decided to take my love of all things audio and do something I've been meaning to do for years... build my own pair.

I want to start with as simple a project as possible (from a technical standpoint) so I've elected to build a pair of speakers to put in my wife and I's bedroom that have no crossovers.

So here's the criteria for the speakers:

- They don't need to play loud at all, moderate volumes in most any situation.

- I don't want to deal with building a crossover just yet, so I'm opting for a full range driver instead.

- They need to look GOOD. My house is clean, minimal, and for the most part devoid of anything gaudy in appearance.

- My preference for speaker sound is warm and laid back. (Think B&W Loudspeaker midrange...)

With all of that in mind, here's what I've come up with so far... I started by the generally positive word of mouth on this driver:

http://www.partsexpress.com/pe/showd...697993#reviews

Some people say the highs need to be tamed, but I think I'll build and then test to see if I find a notch filter necessary. I went ahead and plugged the driver's specs into WinISD and came up with a comfortable compromise cabinet volume of 938 cubic inches. (15.37 liters) This includes the thickness of 3/4 MDF on all sides...

Starting with "golden rule" dimensions, I then used a 3D program called Cinema 4D to tweak the shape. I used an awesome plug-in (demo version) called PhyTools that has the ability to calculate the internal volume of any polygonal shape I could come up with. It allowed me to view, in real time, the shape of the box changing and still meet my volume requirement.

WinISD gave a recommended port length of roughly 6 inches at 2.5 inches to meet the 70hz tuning point of the driver.

So at this point, I have a few questions before I get started...

- I would prefer to have these speakers front ported, since they'll need to be close to the wall, but is my angled port going to interfere by being too close to the bottom of the cabinet. (See one of the attachments for the wire frame side view)

- This is a smallish speaker to be sure (14.78 inches tall, 7.03 inches wide at the front, 10.03 inches long–this does not include the plint attached at the base) but should I still have some bracing in the middle?

- Most importantly, am I going about this the right way? Am I missing anything obvious at this stage of the game?

Here are the renders I came up with for the speaker design btw. I'm not sure if I like my stand designs because their shapes are so organic in contrast to the speaker's angular characteristics. If anyone sees any red flags, lemme know. Any efforts are appreciated.

[chrisb]

Look very sleek & sexy - getting the paint to look as good as the render could be interesting.

Independent of any changes to the "organic" shape of the stand's upright members, I'd trim the top plate to slightly smaller footprint than the base of the enclosure.

Of course, your query could easily become a dialog on choice of driver,(particularly if you're looking for warm and laid back presentation with metal coned driver in a near field position) or construction material, so to avoid that, I'd make a couple of suggestions:

EnABL treatment to driver cone, perhaps even some extra gloss coat damping - the titanium cone could probably use all the help it could get, particularly in a small room.


Use a flared port, and even though an MDF cabinet of this size should be fairly well "damped", a holey vertical brace firmly engaging the driver magnet to the back of the enclosure would be worth considering.

[chirpie]

Originally posted by chrisb
Look very sleek & sexy - getting the paint to look as good as the render could be interesting.

Independent of any changes to the "organic" shape of the stand's upright members, I'd trim the top plate to slightly smaller footprint than the base of the enclosure.

Of course, your query could easily become a dialog on choice of driver,(particularly if you're looking for warm and laid back presentation with metal coned driver in a near field position) or construction material, so to avoid that, I'd make a couple of suggestions:

EnABL treatment to driver cone, perhaps even some extra gloss coat damping - the titanium cone could probably use all the help it could get, particularly in a small room.


Use a flared port, and even though an MDF cabinet of this size should be fairly well "damped", a holey vertical brace firmly engaging the driver magnet to the back of the enclosure would be worth considering.

Thanks for the suggestion on the stand. That'll be simple to impliment.

I won't be listening to these very closely. In fact, I'd estimate my ears will be sitting about 13 feet away from the speakers.

I was considering this port and just choping it down. It's flared as you suggested.

http://www.partsexpress.com/pe/showd...number=260-478

I did a quick search on "EnABL"ing the driver and found the monster thread... looks like I have some reading to do...

Thanks for the reply!

[planet10]

Originally posted by chrisb
if you're looking for warm and laid back presentation with metal coned driver

This same driver has popped up a couple times. The aggressive resonance this driver exhibits probably gives it a fair degree of listener fatigue (a guess -- i haven't heard them).

And a notch filter may give a flat gross FR but it will never fix the problem.

dave

[chirpie]

Originally posted by planet10


This same driver has popped up a couple times. The aggressive resonance this driver exhibits probably gives it a fair degree of listener fatigue (a guess -- i haven't heard them).

And a notch filter may give a flat gross FR but it will never fix the problem.

dave

I like the straight forward honesty. :-)

I searched for the driver in these forums and thus far only found tests on the driver as opposed to a speaker built with it. Maybe I should keep digging.

Would there be another full range go-to driver that doesn't have the flawed characteristics of the driver I was looking at? I'd like to keep it in the same size (3 to 4 inch range) and I'd prefer not to spend too much since is my first build (maybe $40-$60 each) and who knows how badly this may turn out. :-)

Thanks again everyone.

[gurley123]

I've heard (word of mouth only) that these guys sound pretty easy on the ears.

4" http://www.partsexpress.com/pe/showd...number=264-846
3" http://www.partsexpress.com/pe/showd...number=264-844

Dave, any plans for a micro-mini-Onken with the CSS FR125? That would be a sweet bedroom speaker.

[planet10]

What kind of amp are you going to use with them?

dave

[gurley123]

Chirpie,

Nice renderings BTW

[holdent]

The trouble with many fullrange drivers is that they frequently require a notch filter to get rid of a resonance, and generally need a BSC (unless they're mounted in a wall). They normally sacrifice either low frequency extension (and have greater bass distortion than similarly sized woofers) and/or sacrifice high frequency dispersion and have limited power handling. So I think you won't be able to avoid at least building some type of filter to overcome these problems.

Zaph has tested a number of small drivers here http://www.zaphaudio.com/smalltest/. I suspect for your application the less expensive TangBand (W3-1364S) could be a good choice. Other inexpensive choices include the AuraSound NS3 (available at Madisound) and the HiVi B3s or HiVi B3N. I've built the Zaph designed fullrange project based on the B3S utilizing a B3N (see http://www.zaphaudio.com/audio-speaker18.html). However the drivers sacrifice bass and really need a powered subwoofer for louder volume levels. But as a high quality, cheap starter project, they're excellent. As a plus the HiVi drivers are a very good looking copper color and could be a good match for your beautiful-looking renderings above. [Note that Zaph's project is a sealed box and ported enclosures would not be suitable for the B3N/S or AuraSound NS3 due to their higher Qts figures].

[chirpie]

Originally posted by gurley123
I've heard (word of mouth only) that these guys sound pretty easy on the ears.

4" http://www.partsexpress.com/pe/showd...number=264-846
3" http://www.partsexpress.com/pe/showd...number=264-844

Dave, any plans for a micro-mini-Onken with the CSS FR125? That would be a sweet bedroom speaker.

Cool! I'll plug those in next (looks like they'll model very similarly to the others...).

Reading the reviews, they sound like they match my listening tastes better than the others I had initially stumbled upon.

Thanks for the tip.

Originally posted by planet10
What kind of amp are you going to use with them?

dave

That I haven't decided yet. Most likely it'll be a solid state, but it'll probably need to be an amp that gives off little to no heat since it'll be inside a closed cabinet. (see picture below for speaker placement and the cabinet. NO, the speakers won't be quite that big...^_^)

Thanks for all the feedback!

http://www.kchtenthusiasts.com/web_p...i_k/hk47_6.jpg