Mullard speaker box strange impedance resonances

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
There are lot of advises, very interesting and many thanks all of you! Recommended construction for this speaker is TL or open vent, this driver need "to breath", there are many projects in the net and all are opened.
Vas is pretty big and I am afraid that so large aperiodic box is not suitable for my room

I suppose that reducing enclosure volume will eliminate the lowest bass, which one is not desirable. My target is to suppress range somewhere between low and mid frequencies, they are pretty high levels.

Advantages of 9710 are very high sensitivity (on this box is about 100db 1W/1m) and wide range - up to 17kHz, for my tube stage 2W per channel is excellent. Karlson design is very suitable, but not so easy to design and also dimension are high, looks old and I do not want to leave Mullard box and to give up without fight. :)

Is this enclosure somewhere between bassreflex, horn and open baffle, what you think? And can it has some of their characteristics? Of course this suggestion can be quite brave, but for me it is not typical bassreflex type and my feeling now is that closing or changing the vent will modulate somehow the nice middle frequency by some standing waves ot other side effects. Experiments with port which I did only makes ALL bass (low and mid) lighter and affect middles and scene in negative direction. For me Austrailan Mullard engineers did a very good job and can recommend this enclosure for fullrange enthusiasts.

Ok, as discusses adjusting of damping will be point of my next experiments. I will try putting some wadding cones exactly to speaker rear side, I am afraid that it can reflect to middles?

I am open to receive advice how to remove oldschool cottonwool curtains (original plan, posted by me at the beginning) and to replace with modern damping material, but where, how, how much and on which sides :confused:

Cheers
 
hey P10 what do you think...if the port volume of the original Mullard design was filed with a sandwich of fiber fill layers compressed by wire mesh layers enough acoustic resistance could be achieved to create an aperiodic bung of sorts...?

if Powerpz built the box as per the drawing i wonder if the side panels are vibrating (might be some of the U U Uh is from that) there's no cross or lateral bracing shown in plans, maybe make the "curtain" locations the new home of some holey braces..?
 
Last edited:
Member
Joined 2010
Paid Member
Maybe the solution is to remove one 9710 speaker from the enclosure and block the unused opening as a temporary measure, to find out if the quality of the bass response satisfies your needs. I would leave the curtains in place as that method is an efficient way of reducing standing waves in the cabinet. However I would suggest checking that the vented duct is tuning at a frequency at or just below the Fs of the 8'' speaker.
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.