visaton FR10: 4 or 8 ohm?

[dimitrij]

Hi everybody
i'm getting some Visaton FR10 to retrofit an old pair of 3 liter enclosures that i have laying around. I will go for a sealed box. The question: i cannot decide between 4 or 8 ohm version.
Any advice????
I will drive them with a LM1875 chipamp and eventually with a hiraga "le monstre"

thanks for the advice
dimitrij

 

[mjf]

Hi everybody
i'm getting some Visaton FR10 to retrofit an old pair of 3 liter enclosures.....

hello.
3 liter is a small volume and the 8ohm - fr10 has a qts=0,67 and a vas=2,9l.
i am afraid this will give you a boomy bass...........i used 10l with my fr10/8ohm and the box volume is not too big (i will increase it to 12l or more).
i think the 4ohm version qts=0,54 seems to fit better into a 3l box.

Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
greetings.............

 

[dimitrij]

thank you for the advice, i but i feel a bit confused about it, since i read the following from
the strassacker site:

FR-10 8 ohm recommended cabinet 1:
closed cabinet with 1,6 L volume
from 128/81 Hz (-3dB/-8dB)

FR-10 4 ohm recommended cabinet 1:
closed cabinet with 1,8 L volume
from 124/78 Hz (-3dB/-8dB)

I mean, the recommended size of the enclosures are very small: should i trust these information?

for reference:
Strassacker: Lautsprecher - Boxen - Selbstbau

 

[chris661]

I'd doubt cabinets so small could do as they say, there would also be a big bump in response above the rolloff, if you were to use a box so small.

 

[dimitrij]

i checker the bass response using the classical calculation for a sealed box
using the software at Closed Sealed Speaker Box Software Online Enclosure Design With Frequency Power Graph
with the visaton FR10 and a Qts of 0.72 i get:

Vb = 2.909375 liters
f3 = 113.67925260491 Hz
fb = 115.71428571429 Hz
dbpeak = 0.0054747422811946 db

which sounds good for me, since the bass response seems quite well damped

 

[mjf]

Quote:
3 liter is a small volume and the 8ohm - fr10 has a qts=0,67 and a vas=2,9l.

oops......there is a little slip of pen ..........vas = 2,3l as shown in the datasheet.
greetings...................

 

[dimitrij]

ok. i did some calculations. now i'm asking for a blindfold question: which response do you like best?
The one on the left, or the one on the right?

thanks
dimitrij

 

[Juergen Knoop]

the right one! Small speakers don't suffer from higher Qtc as larger ones usually do. The higher Qtc compensates a little bit for the nonexisting bass response, and the effects of room response and ringing are less important with smaller speakers because of the lower sound volume and the listeners hearing threshold.
Regards

 

[syntheticwave]

Hi everybody
i'm getting some Visaton FR10 to retrofit an old pair of 3 liter enclosures that i have laying around. I will go for a sealed box. The question: i cannot decide between 4 or 8 ohm version.
Any advice????
I will drive them with a LM1875 chipamp and eventually with a hiraga "le monstre"

thanks for the advice
dimitrij

Dobre Wetcher Dimitrij,

4 or 8 ohms dependent from the supply voltage of the LM1875.

Formula is P= U*U/ 8 RL

From U you must subtract 2*0,2 Volts for UCE sat of the transistors. The resulting power must fit the loudspeaker.

H.