Uneven speaker response

[Pharos]

I agree Matt, but the excursion resulting from Xmax is so high with LF that blockage of airflow occurs, airflow being much less as F rises, and of course the port is ineffective in mid frequencies.

[farflungstar]

Lol - could you explain that in English hahahah

[Pharos]

Xmax is the maximum excursion of a cone in one direction on its axis, which is highest at lower frequencies.

F used for frequency.

LF used for low frequency.

[fatmarley]

I agree Matt, but the excursion resulting from Xmax is so high with LF that blockage of airflow occurs, airflow being much less as F rises, and of course the port is ineffective in mid frequencies.

I'm not quite sure what you're are trying to say.

Below the port tuning frequency excursion Is usually high (can go through the roof with some drivers). At the port tuning frequency excursion Is low because the port is doing most of the work.

(Xmax Is maximum LINEAR excursion)

[farflungstar]

So wadding could account for the abrupt cut-off?

The ANe only have wadding in the top third of the cabinet around the drivers. I've reached into the port and cab touch the inside of the baffle so I don't it's dropped. Maybe it's too close to the driver....

[Macca]

Cold it be the crossover? Something has gone bad and is acting as a high pass filter? Otherwise it is the driver - which must be a weird fault to give the effect described.

[farflungstar]

The driver puts out equal energy down to all but the lowest octave. It then cuts/stops.

[Firebottle]

This seems such a weird one.
You haven't got the speaker in a null in the room response have you? I'm sure it is unlikely but had to ask.

[farflungstar]

No - the opposite in fact. That side of the room has a better low frequency response

[Pharos]

Without wishing to give a full description and analysis which is time consuming and accessible in text books, I think what I have said is clear, coherent, and accurate Matt.

Yes the role of the port is to augment bass and in so doing it reduces the cone excursion at and around f0, and below resonance the excursion of the woofer is decreasingly controlled to the point at which it is not at all, the O/Ps being in antiphase.

The particular ratio of excursion of the woofer and port air is design and alignment dependant; it is not a fixed ratio.

I am merely asserting that near resonance, where the port is functioning, wadding may be impeding the air flow which is relatively high under those conditions. As Colloms said, there should, in a well designed system, be no need for internal damping at bass frequencies, and this implies that there be a large void internally to allow airflow at these frequencies.

Wadding may have been displaced and be blocking airflow at the port.

There are pictures of the inside of Tannoys illustrating just such an approach; the wadding is fixed to the walls to not impede airflow at LF.