Sealed Volume 2x12 and a TB?

[T101]

Hi,

It seems that I need some new speakers and they need to be able to stand near by a back wall and to be no bigger than 35x40x110 cm. (14x16x43.5 in)

No demand for high SPL, but rather for 25-30hz@0 db or as close to that as possible.

Here I have access to TB speakers and those: VKN 12211/311 - they are kind of legend here... and cost about 47$ - don't be mislead by the price - it's manufacturer's price for the local market, in Scandinavia they are sold under the Gamma brand and are asked much more appropriate prices

Generally I can deal with crossover and tweaking, but I can't deal with enclosures.
I must say that I'm not an enemy to the correction circuits - such as RL in parallel for equalizing the low end.

It would be great if I use 2x12 in per speaker and a fullrange.
With the given size the internal volume would be about 100-110 liters when the bracing is accounted - if it is possible it to be smaller it would be better.

Also I'm kinda not fluent, but used to the Edge baffle and OB calculator so I can make an OB for the fullrange, but that would reduce the height of the enclosure for woofers.

The questions are:
- Is the data from the given link enough to calculate an enclosure;
- which TB speaker in the range up to 60$ per speaker should I use for best results and in what enclosure - sealed or OB (I like OB)
- what should be the enclosure for the woofers - vented (a hole somewhere only to decrease compression resistance such as the ones big Infinity's have), BR or sealed? (tend to prefer sealed)

Haven't used a FR yet - only tried some garage made and wasted some plywood on it without sonic success.

Another consideration would be that the FR from TB that you recommend me is a close in size to some Fostex driver, because if it turns out the project to be success I might go to Fostex... if Fostex is really better than TB of course.

The aim is SQ, balanced sound with good low's and good bright solo drums.

[Inductor]

Hey T101,
They look good.
You need T/S parameters and the frequency curves.
You can also have them measured if you like them.
You say you have a link to the full set (parameters) under another brand?!
You can always play with them to have a feeling.
You need Sd, Rdc, Mms, Fs (a measured parameter would be good)... also (the same) for the curves when doing the xover for an accurate design. For both drivers (2xLow/Mid).

[T101]

Here is where I am now:

I'm probably gonna use the 8 ohm version of the 12 inch VKN - single per speaker for now.
It has QTS of 0.58 and VAS of 264L

So a 145-160 litre Aperiodic enclosure seems sufficient to bring the f8 to 25-28 hz and the f3 to under 40hz - pretty decent for me.

From what I have researched I have chosen that TB driver: http://www.tb-speaker.com/detail/1208_03/w3-871sc.htm

Straight response - no dips and peaks and 87 db sensitivity.

Since the bass is rated as 91 db sensitivity and a first order series crossover at ~1250 hz is chosen, this leaves us in danger of shouting mids...

So I calculated the baffle step with EDGE and designed a correction circuit for the bass only.
That way we end with 87+6 db=93 db sensitivity for the full range - maybe it'll receive an ohm or two series attenuation, maybe not - depending on listening impressions and/or measurements.
And we'll have the baffle step of the bass attenuated with the L2-R3 circuit
+ A bonus - some -1 db@50 hz and -2db@80 hz which will bring up some more low bass.

Any crossover advices and comments are very welcome!

I'm still considering the enclosure of the TB - whether it to be a very open Aperiodic, sealed, aperiodic with whole back an aperiodic vent, aperiodic with parts of the three sides vented or an OB... and what volume...

Here is a link to Sansui speakersSansui Speakers

I am quite tempted to make some variation of the LM series tweeter enclosure:


It actually occurs that I have come to the idea of building some kind of variation of the Sansui LM speakers - I found that after I made the sketch of the enclosure and began thinking about the enclosure for the full range...

Enclosure is the fourth attachment - note that the lilac net is an aperiodic vent and it should be on the other side too and on the top with the same depth too... - I didn't finish the drawing...

Some question about the aperiodic vent placement, orientation and size arise too. I consider 15x30 cm (6x12 in) either in the low part of the back or of the front... should it be horizontally or vertically oriented?

Absolutely any comment or advice is welcome and appreciated as I don't know much about the enclosures!

p.s. don't mind the mic position at the screenshots, I have set the distance to 100m so the position doesn't play a role in the response plot.

[Inductor]

Originally Posted by T101

That way we end with 87+6 db=93 db sensitivity for the full range...

If you say the woofer is a 91dB (in a 2-Way), then 91dB-~4(BSC)=87dB to match up with the 87dB mid/high frequency, what is very fine or I'm missing something. You probably can bring the xover to the 400Hz.
The woofer looks nice. I don't believe the 25Hz (Fs) thing, should be nice, close to the 23Hz of the Kef B139. You should measure them yourself for adequate sized boxes.

[T101]

Originally Posted by Inductor

If you say the woofer is a 91dB (in a 2-Way), then 91dB-~4(BSC)=87dB to match up with the 87dB mid/high frequency, what is very fine or I'm missing something. You probably can bring the xover to the 400Hz.
The woofer looks nice. I don't believe the 25Hz (Fs) thing, should be nice, close to the 23Hz of the Kef B139. You should measure them yourself for adequate sized boxes.

You are not missing anything, the woofer and the fullrange have 4 db difference in the sensitivity. Having in mind that they will be on the same baffle, leads to the conclusion that the woofer will receive a 6 db BSC and the tweeter wiil receice nothing or only a 1-2 ohm resistor.

I prefer the 6 db BSC, because that will lower the 45-50 hz level with ~1db and the 80 hz level with 2 db and so on... - thus low bass will be elevated from -8 db at 26-28 hz to -6 at 26-28 hz... which is quite good... and the -3 db point will occur at around 34-36 hz... So this will be a 34 to 21 khz @-3db @91 db@1w speaker - quite high standard for a garage made DIY costing around or less than 300$ in total.

Of course I'll have them measured. The 25hz resonance is not under doubt - they are an old design and quite well known here... kind of a legend.
And they really go to 4 khz - there are designs where the 12 inch VLD is paired directly to those VLD 40

Today I placed an order for a pair and now we wait... and I'm still not knowing anything about Aperiodic enclosures...

EDIT: http://www.lautsprechershop.de/tools..._closed_en.htm is this a reliable calculator? I'm asking because I'm not keen with "Bass Box".
Can someone who knows "what and how" run a simulation of aperiodic with the 8 ohm version this http://vissokogovoriteli.bg/products/VKN-12211_311.htm
Aperiodic would be a short and relatively small vent or a larger sealed box equal to a smaller aperiodic??? Both overdamped...
We're aiming for 140-160L actual box internal volume.

[planet10]

Re the VKN drivers you posted.

A single 8 ohm would give you good sealed butterworth response in a 540 litre box.
The 4 ohm, a single would fit into 100 litre, F3 ~43 Hz, F10 ~24 Hz.

2 drivers would require 2x the volume.

dave

[T101]

Thank you! It is always better to have an opinion from someone "who have been there".

Some questions have arisen.

What about 2x4 ohm in series in 200L sealed or 120-150L Aperiodic enclosure?
And what about a single 4 ohm in ~100L and Aperiodic?

The other options are not considered, because they are way too non practical.

If it is possible to achieve the 540L response of the 8 ohm version with under 200L Aperiodic enclosure it would be best. But is it possible?

[T101]

The first 4 12 inch woofers are present.

Rather old ones in perfect condition two have served dutie in 50L sealed enclosures and two have served in ~80-100L bass reflex. The difference in the suspension stiffness is easily detectable by pushing the membranes.

Now we wait for the 4 brand new ones to arrive.

We (me and a friend of mine who is the owner of those for the last 17 years) were hoping for the AlNiCo versions, but they are standard ceramic magnet versions.

Never the less they have absolutely beautiful and balanced sound, they even reproduce cymbals - no surprise there are designs where those are paired directly to a ribbon tweeter. A true super extended range paper cone woofer! They are rated 25hz-4khz with average of 91 db@1w spl between 100hz and 4khz.

Paper membranes in paper's natural color. The new ones have the same membranes in theory, but are painted black.

When the new 4 arrive, we'll have all 8 woofers measured and see which ones suite what enclosures. For now i am even more convinced that the 1250 hz first order series crossover is the ONE for those!

I am very happy!

[T101]

Still in preparation phase... But what a preparation it is...

You know, I suffer from a disease, it's called EyeGreed or Greedy Eyes

4x8 ohms and two 4 ohm speakers.

And the Tang Band! I know it is a 30$ 3 inch full range with a miserable ~50-60 mm membrane, but it made my jaw drop with it's scene and good dispersion. I have never owned a full range of any kind (except for one pair of garage grade) and the sound is very satisfactory to me. I am after the imaging mainly.

Now we wait for me to construct speakers of some sort.

Best regards to all!

[T101]

Here are the actual measurements of 11 12 inch VKN's.

From E1 through E5 1 to 4 hdve served in bass reflex and 50l sealed two by two, E5 is a never used 4 ohm which have been kept poorly in an industrial warehouse.

T1 to T6 are brand new, onlt T1 has some break in of about 2 hours without enclosure with bass ckrancked up.
15 years difference in age between the newest and the oldest one. At least 3-4 different series.

I am glad with the results, the engineers who took the measurements (manual data aquisition) said that the data is above the minimum satisfactory level.

What is on my mind is either about 125L enclosure with damped bass reflex port with diameter of 160 and lenght 260mm (~20ms group delays before applying aperiodic damping) or 140-160L aperiodic enclosure.

T2, T3 and T5 seem a good match to me?

I'm not very keen in the enclosures and due to lack of experience I can't make a decision between a 20 ms GD enclosure with steep roll off that goes little deeper and a 10-12ms GD enclosure with more gentle roll of that has ~ 34 hz @ - 5 or -6 db.

Will be glad to hear your opinions and recomendations.

p.s. have in mind that I am going to use a BSC (or a sort of... as described here: L here, L there, L Everywhere *-*) to kill some 4 to 6 db from the bass driver, so the - 3 db point as well as all points of the roll of are expected to be raised to some extent with some db.

Best regards!