Focal Polyglass thiele-small parameters

 

Bronze Member
Username: Zneon

MEXICO

Post Number: 43
Registered: Jun-04
Hello, it's been a long time since my last post. I have some speakers laying around, the Polyglass 165V3E, I removed them from my car because I upgraded to DLS Iridium, but I feel bad for them... Just collecting dust in the the attic.. So, Instead of letting them die, I thought about making a SEALED enclosure for them, for my home theater, considering the thiele small parameters, but I just couldn't find the thiele small parameter. Anyone here knows where I could find the info? Thank you in advance!
 

Platinum Member
Username: Glasswolf

Columbia, South Carolina

Post Number: 14424
Registered: Dec-03
those are designed to be door speakers, which means they are ideally designed to be used in an IB setup, not a sealed enclosure, so really the size of the enclosure won't make too much of a difference. I'd just go with a largish bookshelf enclosure, and use MDF or HDF for the boxes, then veneer them with something nice like a rosewood veneer, and put nice binding posts on the back.
Maybe make some nice magnetic grilles for them too. parts-exoress has all the stuff you'd need to make the enclosures, save for the veneer. you can google for that. veneers run anywhere from $5 to $25 per sq foot.
 

Bronze Member
Username: Zneon

MEXICO

Post Number: 44
Registered: Jun-04
Thanks glasswolf, do you believe size of enclosure won't make that much difference? Because I already found the specifications and I want these focals to sound as good as possible. I want a tight, not deep bass from the speakers, (I have 12" sub) so I thought about a sealed enclosure. I asked Perry Babin (bcae1.com) about the enclosure but no word from him yet. And yeah, I thought the best thing about this project is making them look really nice, I tought about cherry wood veneer but now that you say it, rosewood looks nice too. So all in all, should I just pick any number for the enclosure? Say .6ft3? Anyway here are the specifications for both speakers.

6.5" Driver
Fs: 83.24 Hz
Vas: 0.242 ft3
Qts: 0.83
Qes: 0.9
Qms: 10.72

----------------------------------------------

4" Driver
Fs: 117.66 Hz
Vas: 0.05 ft3
Qts: 0.811
Qes: 0.88
Qms: 10.41}
 

Bronze Member
Username: Joe1234

Post Number: 99
Registered: May-09
Here is some software if you want to check, pick the 6.5" driver for a sealed enclosure to see what you get just for fun:

http://www.linearteam.dk/default.aspx?download=winisd

here's the publisher's home page:

http://www.linearteam.dk/

You may be able to better approach a specific response that you may want. However these speakers are optimized to work on a door's wall which can be modeled as an infinite baffle.
 

Bronze Member
Username: Zneon

MEXICO

Post Number: 45
Registered: Jun-04
Wow! Playing with that software made me really understand why Glasswolf said they work better in an IB. The speakers have a big QTS value, .83 and .811, so that means that I would never be able to achieve a QTC of 0.7071. I tried different values in the software, and it turns out that I need a 20 ft^3 enclosure to get a value of .84 QTC, which in other words would be an infinite baffle!!

So basically I can put the speakers in a single MDF sheet and that's it! joe_durkham thank you very much for the link and glasswolf thank you for your recommendations.
 

Bronze Member
Username: Joe1234

Post Number: 100
Registered: May-09
Ok but that would need to be a very big sheet, besides there are practical reasons why is better to use an enclosure: the surface in which a speaker is installed should not vibrate at all or there will be distortion on the emitted sound wave and that gets worse when the material resonates within audible frequencies, Speakers then will be better off installed inside a heavy big thick enclosure which can be open on the back.
 

Platinum Member
Username: Glasswolf

Columbia, South Carolina

Post Number: 14431
Registered: Dec-03
yeah you can box the speakers in a sealed cabinet. you'll be sealing the backside into a separate chamber than the rest of the room you're in, so it will help. The size of the cabinet just isn't "critical" per se.
Make some nice bookshelf cabinets, put the drivers in, and veneer it in something pretty.
My personal favorite is Bubinga, but it's a little costy for the premium grade stuff.. although you're only talking about a couple square feet of it anyway. When I do a full floorstanding pair of speakers, it's like $400-500 in veneer.
 

Bronze Member
Username: Zneon

MEXICO

Post Number: 46
Registered: Jun-04
Thanks guys, I'll come up with something good and pretty, I'll post once I have the material
 

Silver Member
Username: Joe1234

Post Number: 103
Registered: May-09
noumenarete, before you proceed take a look at this:

http://www.diyaudio.com/forums/multi-way/101872-car-components-home-speaker.html

Now my take is that if you are going for sealed enclosures make those rather large, at least in theory those should contain a volume as large as the volume inside an average car door to match the environment for which they were designed for, maybe you could go tighter without any issues but think twice about what you should build.
 

Platinum Member
Username: Glasswolf

Columbia, South Carolina

Post Number: 14437
Registered: Dec-03
Try something similar to this

Upload

Upload

Upload

Upload
 

Bronze Member
Username: Zneon

MEXICO

Post Number: 47
Registered: Jun-04
I like the texture, but I was thinking about something a bit more reddish, before I buy I'll go today to check out veneers in a specialized store, the speakers themselves are beautiful so I'll try to make the enclosure as pretty as possible, stay tuned and thanks for the images!

BTW when I searched for open back baffles, I found this!
Looks nice!

Upload
 

Silver Member
Username: Joe1234

Post Number: 107
Registered: May-09
With that one you will get excellent performance but will lose much if not most of the lower end.

If you opt for an open enclosure type just make a normal enclosure but as deep as you can open on the back. That will help it to behave as an IB.
 

New member
Username: Cytribe

Post Number: 1
Registered: Aug-11
I took my Focal 165K2Ps to a home audio shop and they made up some custom boxes, beautiful sound. Upload
 

Silver Member
Username: Joe1234

Post Number: 232
Registered: May-09
Look nice, do you have the specs of the enclosures?
 

New member
Username: Cytribe

Post Number: 2
Registered: Aug-11
Unfortunately not, I basically just gave them to the shop, threw money at them, and wound up happy with the result
I know that this is frowned upon in audio circles but I don't know enough, or care to know enough about home audio to get into the fine details.
I'm far more into car audio, where I'm perfecting my Focal set up.
 

Platinum Member
Username: Glasswolf

Columbia, South Carolina

Post Number: 14476
Registered: Dec-03
The only thing to watch here is that you're dealing with 4 ohm drivers, which will result in a 4 ohm speaker cabinet/setup.. and a lot of home audio/home theater AV receivers are only 8 ohm stable at the amplifier stage.
As an example, my KEF Reference speakers are all 4 ohm home speakers, as are my Martin Logans. They are on dedicated amplifiers, but while my Onkyo AV receivers are rated to handle 6 and 4 ohm loads, I have a kenwood AV receiver that is only 8 ohm rated, and even with a nearly flat resistive 4 ohm load, the amplifier still shows clipping even at low background music in a small bedroom volume levels. It just can't handle the low impedance.

Now, if you happen to have some emotiva, adcom, hafler, etc amplifiers to drive the speakers, it won't be a problem.
 

Silver Member
Username: Joe1234

Post Number: 250
Registered: May-09
Just curious Cytribe is just that I think I see a port on the speaker next to the tweeter, those speakers are not usually setup that way but if you like the results then somehow those guys knew what they were doing.Anyways if you ditched these you may have gone for 3 ways or maybe utopias!!
 

New member
Username: Cytribe

Post Number: 3
Registered: Aug-11
Joe: I actually downgraded! I was set to put them in my car when it was broken into and the old stereo ripped out. Having spent my hard earned cash on the 165K2Ps, I didn't want to see them go the same route and made the decision to put them into home audio speakers instead.

Move forward a few years and I've built another Focal system for my car, the Polyglass 165 V 30s are in the front with a 33V1 sub in the back.

As far as the port is concerned, it actually hasn't effected the sound quality at all and I haven't yet found a volume my ears can take where it clips in any way.

If I had the cash I would have Utopia 3 ways in my car in a heartbeat. Focal make some damn fine home audio that I would get instead of converting again.
 

Silver Member
Username: Joe1234

Post Number: 256
Registered: May-09
I know, the K2P are too good and expensive to just see them gone, and with the utopias it must be a nightmare.

Some weak home amps (British?) get really upset working with 4 ohm loads, but focals are very high sensitivity so I am not surprised that you are not having trouble.

Never heard their home audio stuff but there are lots of high end eccentric stuff there even in the hudreds of thousands per pair!.

The port, well never mind lol,. I guess I will figure it out later.
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