Yes Ssf, the D225 port is well integrated in the cabinet with a gap which is visible in the cross section.In the design of the D225's, it's the Port, the baseplate, the rubber speaker supports which finally is placed on stands.
Yes Ssf, the D225 port is well integrated in the cabinet with a gap which is visible in the cross section.In the design of the D225's, it's the Port, the baseplate, the rubber speaker supports which finally is placed on stands.
Point well noted, thanks.By locating the port at the bottom, the port is always at a constant distance from the boundary unlike if it is located at any other place on the speaker box. This will help the designers to fine tune the box tuning at the design stage itself.
To what?Front ported is much better suited.
WOW! This is an active thread ! 2 Pages and it began at noon today....Hi FM's,
As the title says, is this due to aesthetic or scientific reasons ?
The issue being that as the rear ported speakers need a decent amount of space behind them to sound proper and space is a premium for most of us due to lack of dedicated rooms
If the experienced FM's could shed some light on this would be great. Thank you.
That affects the location of the port on a given plane. Does not affect rear/front placement of the port.If only things were so simple.....
The Length the wave travels, determines if the Port output is a Node or anti-node.... Just like in a room, where the speaker creates Nodes and antinodes at multiple points in a room....
WOW! This is an active thread ! 2 Pages and it began at noon today....
My core expertise is not in Loudspeaker design, but my understanding is:
1. A port moves air into the room.... Just like a speaker driver does.
2. The Port is "Tuned" to move the most at typically in the LF (Low Freq) when the the driver output rolls off.
The Output from the port is meant to AUGMENT the (rolling off) LF from the Woofer.
Hence it is essential that port Port's Output is IN PHASE with the LF driver, if the port is located on the same face as the LF diver (usually on the Front Face)
If the Port's output is Out of phase with the LF Driver, then the Port MUST be located at the rear of the speaker, if the Woofer is on the Front Face of the speaker.
Its Only if the Port Output is in phase with the speaker, that the port can be located on the Front face of the speaker.
The Output Phase Of the port, I believe is the PRIME Criteria for deciding the location of the port... Front or Rear of the speaker.View attachment 67718
To what?
Let me put it this way:
In 2 speakers, all other things being the same EXCEPT the port location [front & rear]:
1. if the speakers suffer from the issue that @Vineethkumar01 mentioned in Post # 7, the front ported speaker will sound worse than the rear ported.
2. if there is inadequate space between the port outlet and the wall, the rear ported speaker will sound worse than the front ported one.
Isn't this the intent of all speakers, bass or not?None of them are rear ported as the intend is to provide the best bass effects to the listening area / dance floor.
Trying to understand this (in relation to port placement) Wavelength can be found by dividing the speed of sound in feet which is 1,130 feet / second by the frequency we need to find the length of. Dividing 1,130 by 40 produces a quotient of around 28 feet. Therefore, a 40 Hz. wave is 28 feet long….If only things were so simple.....
The Length the wave travels, determines if the Port output is a Node or anti-node.... Just like in a room, where the speaker creates Nodes and antinodes at multiple points in a room....
just noticed the mistake. All wavelengths are valid for 20Hz. For 40Hz, everything should be divided by 2.Hi @IndianEars,
I think the argument of port output cancelling the woofer output due to phase mismatch is not valid for typical bass reflex designs (transmission line type designs need a bit more deeper thinking I guess due to the long lengths of the tunnel). The port is a helmholtz resonator, whose output peaks at the tuning frequency. At the tuning frequency, the driver works minimum. Port works maximum in producing sound output at that frequency. You can see this in my measurements here: https://www.hifivision.com/threads/audibility-of-port-resonances.85679/ around 38 Hz, where there is a notch in driver output and a peak in port output.
Above and below the tuning frequency, the port output reduces, (ideally) to the point that it acts like a port is not there (leaving aside pipe resonance frequencies). Below the box tuning frequency, the port essentially acts like a hole in the box. this will cause leakage of frequencies out of phase with the drivers sound (comes from backside of the driver) and cause cancellation (hence the 24 dB/octave fall off in low frequency output in bass reflex boxes unlike a 12 dB per octave sealed box fall off).
Also, think about the wavelengths at the low frequencies, at a 40 Hz tuning, we have a full wavelength of 17m. Hence the path length difference between port output and driver output is of the order of less than half a meter (typically). We need about 8.5 metre (180 degrees out of phase) of path length to create destructive interference between driver output and port output at this frequency.
making sure the speaker is compact, aesthetically pleasing and meets the price point the manufacturer wishes to target. These three things (size,aesthetics,cost) along with brand name drive the consumer speaker segment in my view.
As a side note I honestly believe that 90%+ of consumers would be better served with a cheap Behringer professional speakers with a 10-15" woofer and CD along with a DSP/Pro amp. The problem with this approach is that it is larger and more complex. Consumers often will perceive it to have low "fidelity" compared to equally priced home audio speakers and perhaps above all consumers are not comfortable with this notion of using professional speakers at home.
Home audio speakers come in all sizes, so no question of size restriction. Price point, again, home audio speakers cost much more than their pro counterparts, so, not restricted by price either. Aesthetics is probably the only aspect that is given equal or more importance than sound quality.
My observation has been that pro speakers are all about delivering maximum wattage. Their horn tweeters are designed to project and emphasise higher frequencies over a larger area, and have a tendency to sound harsh, and are also directional. Horns do an excellent job in an open area setting.
Soft dome tweeters, popular in home audio, have better dispersion, and they sound smoother, ideal for close-proximity listening conditions of a typical home audio set up. Again, exceptions to use of horn loaded tweeters in home audio exist, e.g Klipsch. They deliver higher dynamics, but can get fatiguing in a close-proximity environment.
But, there are pro speakers with horn tweeters that sound sweet, as well, exceptions exist, but they do come at a higher price point. I do agree that a well made pro speaker can sound fantastic, and at a much lower price than its home audio counterpart. It's just that their ABS enclosures that make them less than ideal, from a home decor point of view.
This is in fact, a great query. This piqued my curiosity and i've been mugging up a lot on this. And, it appears that this has been a common topic on all popular audio forums. There have been various reasons, from technical to aesthetics. But, there has been no ONE definite answer. It'll be interesting to know more about this directly from a speaker designer.Hi FM's,
As the title says, is this due to aesthetic or scientific reasons ?
The issue being that as the rear ported speakers need a decent amount of space behind them to sound proper and space is a premium for most of us due to lack of dedicated rooms
If the experienced FM's could shed some light on this would be great. Thank you.