Hi folks,
Do you think there's difference in bass perception? Of course we put the probably difference in tuning into the equation. Let's assume they get the same tuning overall.
One point to think of is the omni dispersion of the bottom firing port. But at low frequencies (40Hz tuning where my project is), rear port should be omni dispersing as well, no?
Do you think there's difference in bass perception? Of course we put the probably difference in tuning into the equation. Let's assume they get the same tuning overall.
One point to think of is the omni dispersion of the bottom firing port. But at low frequencies (40Hz tuning where my project is), rear port should be omni dispersing as well, no?
The perception no because the wavelength is too long. The output of the port yes sometimes. Nearby surfaces can modify the performance of the port and these tend to be different for downward and rear ports. It is not uncommon for a downward port to use the gap between the bottom of the speaker and base as part of the length and flaring of the port.
edit: sorry did not read the initial post properly...
anyhow, upper frequency response will be slightly different, rear port probably attenunating higher frequencies more. but it mainly depends on floor material.
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As above, but given the choice during the design phase (domestic speakers; PA are always front), I'll always do downfiring as I like to incorporate an external flare on the base plate to guide the port airflow to some extent. Plus I generally use some sort of controlled directivity so I design so I can place close to a wall.
If there's no baseplate in the design, downfiring onto carpet I think removes a bit more of any higher freq content from the port rather than it bounding off a hard rear wall. No measurements, and one of the few take it on faith generalities I use in design. Downfiring often means a straight port and can simplify the internal design if it's factored from the start.
If there's no baseplate in the design, downfiring onto carpet I think removes a bit more of any higher freq content from the port rather than it bounding off a hard rear wall. No measurements, and one of the few take it on faith generalities I use in design. Downfiring often means a straight port and can simplify the internal design if it's factored from the start.
Depends on the box, and the room, and the measurement location.
I prefer front port if it's properly done, but if it's not done properly there's no point.
Only port placement that does not work very well is if you're making an upwards firing port on something like a small bookshelf speaker.
IMO down firing is better than rear firing because it's a "constant" that's closer to equal between speakers.
I prefer downfiring with large speakers.
With downfiring you incorporate the constant distance between the pipe and the floor in your bass reflex design.
You can put the speakers close to the wall.
Another detail, I put the downfiring port closer to the frontpanel than the backpanel, so the route of the drivers to the port is not obstructed with damping material.
With downfiring you incorporate the constant distance between the pipe and the floor in your bass reflex design.
You can put the speakers close to the wall.
Another detail, I put the downfiring port closer to the frontpanel than the backpanel, so the route of the drivers to the port is not obstructed with damping material.
Thanks a lot guys, this is some food for thought!
The speakers we're talking about will be MLTL floorstanders. And I have the chance to put a sloted port in the rear or bottom. There will be a crossover compartment in the bottom isolated from the main internal enclosure. No bottom base will be used, but there will be a fixed distance from the ground using feet.
If I were to use a down firing port, there's the benefit of taking advantage of the crossover compartment, making the port length external and adjusting it will be easier.
The speakers we're talking about will be MLTL floorstanders. And I have the chance to put a sloted port in the rear or bottom. There will be a crossover compartment in the bottom isolated from the main internal enclosure. No bottom base will be used, but there will be a fixed distance from the ground using feet.
If I were to use a down firing port, there's the benefit of taking advantage of the crossover compartment, making the port length external and adjusting it will be easier.