Is driver sensitivity affected by cabinet volume and port size?

[BmWr75]

The Tang Band full range drivers in the photo below are rated 90 dB sensitivity (8 ohm driver, 1 watt/1meter). Modeled the driver in a vented box and came up with 0.56 ft3 box and a 2" diameter port 3.75" long. Finished the build today. In general, does box size and port sizing affect speaker sensitivity? I ask because these speakers seem easier to drive than other speakers owned with the same rating.

Edit: should have mentioned no crossover was needed for this full range driver. My guess is the 90 dB sensitivity rating on the other commercially sold speakers is optimistic, and yes I know the difference between 1 watt/1 meter and 2.83V/1 meter.

 

[opnly bafld]

What was the modeled F3?

 

[BmWr75]

What was the modeled F3?

58.5 Hz

 

[hopeless]

With a driver designed for a larger enclosure, yes. Otherwise the driver will act unloaded with the oversized enclosure. Definite "maybe"

 

[Pete B]

No

 

[opnly bafld]

58.5 Hz

Do the other speakers play lower?

I have Fostex FF85WK's in micro Fonken cabinets and even though the drivers are only rated at 87dB the speakers seem to play as loud or louder than larger speakers that are rated at 90dB, I always assumed this is due to their response dropping off a cliff at 80Hz. I have noticed similar results when comparing other speakers.

 

[malden]

Could be wrong but I seem to recall reading a JBL document from the 1960's that gave various enclosure volumes and port sizes for a particular driver where they state that increasing enclosure volume increases bass response at the expense of efficiency.

 

[opnly bafld]

Edit: should have mentioned no crossover was needed for this full range driver. My guess is the 90 dB sensitivity rating on the other commercially sold speakers is optimistic,

 

[BmWr75]

Do the other speakers play lower?

Doubt it. The speakers sitting in the same location before today were Shinjitsu Little Hiros, also rated 90 dB sensitivity.

 

[opnly bafld]

Doubt it. The speakers sitting in the same location before today were Shinjitsu Little Hiros, also rated 90 dB sensitivity.

Using a Mark Audio driver that the manufacturer rates at only 85.4 dBs?

 

[Gigantic]

Could be wrong but I seem to recall reading a JBL document from the 1960's that gave various enclosure volumes and port sizes for a particular driver where they state that increasing enclosure volume increases bass response at the expense of efficiency.

IIRC, porting will also nominally decrease efficiency.

 

[Apreggiator]

Two thoughts here. Well more, but two regarding this topic.

1. It would be interesting to know what the sensitivity rating of the drivers used in the commercial products you refer to is, not the measured system efficiency of the speaker (box + driver). Just to make sure apples are compared to apples.

Example
The efficiency of the EV DL12BFH 12" driver is rated at 96db (1w@1m) https://products.electrovoice.com/binary/DL12BFH_spec_sheet.pdf
System efficiency of the speakers in which it's used is (1w@1m) 99db for the Sx200 and Sx300.
P.s. All based on EV's published specs.
P.p.s. Just an example I could find quickly, I have no direct experience with these speakers or driver.

2. This Tang Band being easier to drive isn't explained by the above though. Is it lower moving mass? Is it the santoprene surround?
I also wonder why (and if it can be seen in TS parameters and/or if it requires measurement) and am staying tuned to this thread.

 

[Apreggiator]

Using a Mark Audio driver that the manufacturer rates at only 85.4 dBs?

The apples vs apples thing indeed.
Speaker(box) sensitivity rating vs driver sensitivity rating.

 

[bowtie427ss]

FWIW, and not to hash semantics but, box + driver = speaker system. That's the term that should have been used in the thread title in lieu of driver.

 

[Apreggiator]

FWIW, and not to hash semantics but, box + driver = speaker system. That's the term that should have been used in the thread title in lieu of driver.

The problem ime is that the term speaker is interchangeably used and understood to mean driver and loudspeaker. Hence my choice of terminology.

 

[BmWr75]

FWIW, and not to hash semantics but, box + driver = speaker system. That's the term that should have been used in the thread title in lieu of driver.

FYI, I built the speakers in question with the TB full range driver and the only spec available to me are for the driver (which are in the OP). So the questioned asked and thread title are appropriate.

 

[toddalin]

The Tang Band full range drivers in the photo below are rated 90 dB sensitivity (8 ohm driver, 1 watt/1meter). Modeled the driver in a vented box and came up with 0.56 ft3 box and a 2" diameter port 3.75" long. Finished the build today. In general, does box size and port sizing affect speaker sensitivity? I ask because these speakers seem easier to drive than other speakers owned with the same rating.

Edit: should have mentioned no crossover was needed for this full range driver. My guess is the 90 dB sensitivity rating on the other commercially sold speakers is optimistic, and yes I know the difference between 1 watt/1 meter and 2.83V/1 meter.

View attachment 3450874View attachment 3450876

Looking at the freq response, the 90 dB value appears to be based on a frequency of 1kHz, and this is pretty typical of many manufacturers. At 1kHz, I'm thinking the cabinet, and specifically the porting, would have little to do with the rated efficiency.