FRD recommendation

codyt

Member
Paid Member
2019-08-26 7:05 pm
IN, USA
FRD recommendation and enclosure design feedback

I'm finalizing a small bass reflex box design for a single full range driver. I'm at around 0.45cf right now, but can adjust as necessary to the right driver. This is my first endeavor into full range and I don't have experience with many of the brands that I come across in my research. At the moment, I've narrowed things down to the Audax 6.5" 17LB25ALBC or a Markaudio Alpair. I've attached my drawings. I'm limited on where I can place these, so they'll be a little below ear level, hence the 15º tilted baffle. They'll be replacing KEF Q100's.

All in all, hoping for recommendations for 6"-8" FRD's in the $100-200 range and any feedback you have on the enclosure design itself. They'll be driven by a Pass Aleph 30, and I'm hoping for a sensitivity at or above 90db. Primarily listen to jazz, earlier rock, some indie rock, and chamber music.
 

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All in all, hoping for recommendations for 6"-8" FRD's in the $100-200 range and any feedback you have on the enclosure design itself. They'll be driven by a Pass Aleph 30, and I'm hoping for a sensitivity at or above 90db. Primarily listen to jazz, earlier rock, some indie rock, and chamber music.

Probably a tossup between the Alpair 10M & A10p. With the metal A10M, you loose a couple dB compared to the A10p, but you'll gain bass extension. And they are on sale at Madisound too. If you like a more relaxed "top end" then the A10p is for you. And you could increase the size of you enclosure for these drivers to gain back some bass.

Are these doing on stands or are they for near field?

No experience with the Audax drivers, so can't comment.

jeff
 

codyt

Member
Paid Member
2019-08-26 7:05 pm
IN, USA
Thanks Jeff, that’s good info! I’ll be using a powered sub for the low-end, so more concerned with mids and top-end. These will be near field.

Concerning the sensitivity, is there a rule of thumb on how a small bass reflex enclosure impacts the overall number? For instance, if the 10P is rated at 89.5db would I expect to see that same number once I install in the enclosure?
 

zman01

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2011-02-04 11:35 am
Dhaka
codyt,

Instead of tilting the baffle, you can also go for desktop stands that will tilt your speaker. That way you can keep the speaker baffle straight, and have more flexibility on the tilt angle. Some images taken from the web attached to give you the idea.

With the Aleph 30 you should be able to drive any of your choice of wide-band drivers to loud levels.
 

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codyt

Member
Paid Member
2019-08-26 7:05 pm
IN, USA
Those are really nice. Unfortunately I have some height restrictions too. Most of the wedges I’ve found are too tall for my space. It’s essentially a 14” cube with no front or back. Not ideal placement, but the only option I have until I buy a new house or my wife becomes more lenient on speaker placement :)
 

zman01

Member
Paid Member
2011-02-04 11:35 am
Dhaka
codyt,

A 14" cube is plenty space for a decent wide-band bass reflex box.

For example, here's the plan for a simple BR cabinet for the Alpair 10.x:

http://wodendesign.com/downloads/simpleReflex-103-10p-plan-100214.pdf

You can make the cabinet a bit shorter and increase the width or depth. The two important things are the cabinet volume and port size (diameter and length) - those need to be maintained, the H, W, D can be played around with within reasonable limits. Also try to avoid a cube shape - closer to golden ratio is better.

Just one word of caution, in my experience, wide-band drivers sound very nice with genres like jazz, acoustic music, vocals, and Eastern classical, but not so good with complex genres like hard rock or metal. At moderate volumes, Dire Straits sounds fine to my ears, but not AC/DC:)

Btw, curious - what about the KEF Q100 you did not like?
 
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codyt

Member
Paid Member
2019-08-26 7:05 pm
IN, USA
I actually love the Q100’s and am just wanting to have a go at building a wide range pair with more sensitivity. There are a couple low watt amps I’d like to tackle in the future, and I’m afraid the Kef’s (at 86db) would be less than ideal. Thanks for those plans! I may try and adapt mine to something closer to those dimensions. To your point, I think my current drawings are a bit close to a cube in dimensions, though I’m not sure if the tilt factors in at all.

And I’ll save the ac/dc for my headphones :)
 
...driver size. Sounds like I may need to look a bit smaller than the 6-6.5”

I think the FF165wk will fit that small a box, but if you squeeze a bigger driver into a smaller box it can start to lose some openness. But <10 litres would be small for this (optimum miniOnken is 17 liters).

You do not want a box that has the side walls to close to the driver, which can cause shoutinesss.

Alpair 10p is one of my favorite drivers. It measures 90 dB, and with its greater excursion can do more bass than the larger FF165, and is smoother. The A10.3 is as good with slightly different compromises. In my alignment 13 litres is optimum.

Note that each different driver will require a different vent size. And you might find 15° an excessive tilt. I did front, 10°, and 15° baffle versions of the microPlus for FF85wk (yet to be drawn for Alpair 5.2/3.

Here are the aiming diagrams from the planset:

wedgieAim.png


A brief editorial on driver size trade offs (in general, in specific execution makes a huge difference): planet_10 hifi | drivers (2nd box-out).

dave