Designing mid-high speakers to match SUB

**Spadez** · **10-22-09, 04:20 AM**

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This driver is pretty good, but look above

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OB application of midway driver allows you * to use lower order (6 db per oktave) cut off electrical filters. It is very good for impulse response and "group delay" factor.

Does this mean that OB still isnt as good as a sealed box for the size requirement I have? So far, im assuming the driver posted in this post with a 1.1L sealed container is my only option for half decent sound at this size. Is this correct?

**Yad** · **10-22-09, 06:55 AM**

>> Does this mean that OB still isnt as good as a sealed box for the size requirement I have?

yes. Because you want th box size not much bigger than cube with 5-inch sides. For baffle (with every driver) dimensions could be counted as shown above. Even with 1 m baffle you ll have 10 dB loss @100Hz. 6 db point could be reached with 3.4 m sides. (note, i mean the result without deep electronic correction)

**Yad** · **10-22-09, 06:57 AM**

I'm sure - the closed box with good wool damping inside - is the best choice for your application.

OB - is good think, but it does not fits everywhere. But i forgot one interesting application. If you have walls made of hyproc (walls with cavities inside) you also could use them as Infinite baffle (Likely OB, but not dipole). Use usual car-installation drivers and mount them directly in to the wall. Or you may use your chosen drivers anyway. But for such installation the Qts driver-factor should be not less than 0.7 (but not more than 0.9..1)

**Spadez** · **10-22-09, 07:07 AM**

Ok, I'll go with that then. The vifa driver is the best too?
Posted via Mobile Device

**Yad** · **10-22-09, 07:25 AM**

all of them are good. Frankly speaking, I'm not the brand-fanatic ))) You just only should know, what do you want from the driver & the speaker : dimensions/design/frequency range/clarity & details in sound/ or may be wide angle of sound field/ or maybe high Sound Pressure Level/ or only the price matters ///.

I'm only able to decide an engineering part of your task.

The bigger driver needs larger volume. That's physics.

**Spadez** · **10-22-09, 09:02 AM**

The trouble is I dont understand the specs, I just assume the Vifa is the best midrange for my budget based on the information youve given me

I dont mind about the price, the size is the most important to me and so is the ability to go down to 80Hz, but I dont care how high it can go because I will have tweeters.

**Yad** · **10-22-09, 09:19 AM**

that "small" VIFA is OK. If you'll have the lack of HF - you could use small tweeter with acoustic lens

**Spadez** · **10-22-09, 09:24 AM**

When you say its "ok" you make it sound like there is something better though?

**Yad** · **10-22-09, 09:31 AM**

mmm ... this is one of the best possible drivers for your extra-small-sized application ...

**Spadez** · **10-22-09, 10:11 AM**

Ok, great. I think they stop making them soon so I will order them. Two more questions:

1. Does it matter if I point the mid at the ceiling, is it much better to point right at you
2. If I made the design into a rectangle instead of a square design, would this affect the sound?

**Yad** · **10-22-09, 10:26 AM**

I think, yo better show your picture (drawn by hand) here. I'll model it & will show results for you.

**Yad** · **10-22-09, 10:28 AM**

everything does affect the sound. But If somebody will think about all of that factors without exception - he could become crazy )))))

but there are myths also. For example the direction of the wire

**Spadez** · **10-22-09, 10:49 AM**

These are the three im looking at:

1. Cylinder
ID Diameter: 6.5"
ID Height: 2"
Volume: 1.088Liters

1.Cube
ID Width: 4"
ID Height: 4"
ID Depth: 4"
Volume: 1.049Liters

1.Box
ID Width: 5"
ID Height: 6.5"
ID Depth: 2"
Volume: 1.049Liters

I think the cylinder design would be very nice, but you said cylinder is sometimes not so good. The box design is good because it takes up little sufrace area on my desk, but again, may not soind as good.

**Yad** · **10-22-09, 10:53 AM**

well... the cube is better. Are these dimensions are internal ?
Yes the cylinder will have the worth frequency response.

**Yad** · **10-22-09, 10:56 AM**

the model is at the 49-th post of this thread.

**Spadez** · **10-22-09, 11:15 AM**

Hi,

Yes all of those dimensions are internal. Is it possible to model the other two designs. I know the cube may come out best, but this design is also the worst out of the three for my desk space. I would like to know how big the difference is if possible.

**Yad** · **10-22-09, 12:45 PM**

Frequency range would be the same. But the difference will be in fluctuations of the FR curve.
I found one picture for you. I think, it would be interesting for everybody. This picture shows the difference of diffraction distortion between different cabinet shapes.

**Yad** · **10-22-09, 12:49 PM**

According to this picture you can notice the difference and make a decision by yourself.

**Mike P.** · **10-22-09, 02:52 PM**

Yad, what program is that?

**Yad** · **10-22-09, 03:15 PM**

what program do you mean, Mike ? The picture shown at the 92-nd post - was taken from the book.

**mayhem13** · **10-22-09, 04:49 PM**

WhilIe the idea and the thread are interesting in it's goals, truthfully there is little to be gained here over your current bose setup as LF extension is limited in such a small space with current driver technology.....small radiating area=poor LF extension....Not my opinion, but Newton's and the other physicists. I applaud your inspirations, but don't expect too much from this type of speaker. If space is the issue, In walls would be a better approach of which many are available commercially on the cheap.

**Yad** · **10-22-09, 05:04 PM**

yep. it's true...

some 3-inch drivers are able to give flat frequency response till to 100 Hz at the lo end, but no one will never give you a big total SPL level in it's full range (as 8" for example). That's physics : "The sound pressure level is proportional to diffusor's square & diffusor's displacement... and it's acceleration"

But it seems to me, Spades have some specific design boundaries (limits)...

**Yad** · **10-24-09, 11:13 AM**

Hi everybody. I found some links about Open Enclosure (Open Baffle) and Infinite Baffle.

http://en.wikipedia.org/wiki/Loudspe...nfinite_baffle

http://www.diysubwoofers.org/

http://www.troelsgravesen.dk/OBS.htm

**Spadez** · **11-07-09, 07:49 AM**

Yad. Im sorry I havent been on here recently, but your links are really useful, especially the troelsgravesen one, ive got some reading to do!

Can I assume that I cant get around these size issues by using more speakers in a container, which each having only a small dedicated range, instead of trying to get one speaker to do the whole shibang?

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