[Alwayswantmore]

Hi Louis, some of your speakers port to the front. Some -- like my compact hemps -- port to the rear. My compacts also appear to have a flared port. I can't speak for others, but I'd love to know more about what the ports do, and why they differ from speaker to speaker? Is it to increase efficiency, improve or extend frequency response, improve imaging? Or..???

What is the difference between a front vs. a rear port. Assumably a front port can be placed closer to the wall.

Any educational info you can (care to) share is appreciated!!! Thanks, Kent

[woodsyi]

Darn,

I thought you were asking about port wine.  I briefly thought you were asking Louise to tell us if he prefered Dow or Taylor and what vintage. 

[Louis O]

Hi Alwayswantmo,

The only speaker right now that uses the front ports are the Super 3V2 and I do this because this models is perfect for situations that require very close to rear wall placements such as desktop systems and on wall applications for HT.

Check out this link from my manufacturer about the ports I use now.
http://www.psp-inc.com/psp-inc.com/public_html/why.htm

I have switched to the Precision ports a while ago and they just sound better than non-flared ports. There is less noise and the also enhance the bass in terms of congestion.

Hi woodsyi,

Not a big wine drinker, but I do prefer the California wines when I can.

Talk to you soon,
Louis

[ctviggen]

Port wines must be an acquired taste.  The ones I had tasted terrible.  But I once probably thought beer or scotch tasted that way, too.

[woodsyi]

Port wines must be an acquired taste.  The ones I had tasted terrible.  But I once probably thought beer or scotch tasted that way, too.

Bob,

Port wine and Stilton Cheese is like foie gras and Sauterne -- one of the finest food and drink combinations of all time.  Try a good bottle of NV port like Graham tawny port 10 years or Ramos-Pinto tawny port 20 years to go with a good Stilton on water crackers.  I can't believe anyone wouldn't like it.  For vintage, 91 and 92 are drinking now and still available at good price.  Australia makes some really good NV stuff for under $20.  This is my favorite dessert after a good dinner.  If you can sneak in a good cigar it's even better but I find that hard to do in mixed company now days.

Louis, sorry for the intrusion and you can remove it.  But it is about ports. 

[Alwayswantmore]

Hi Alwayswantmo,

The only speaker right now that uses the front ports are the Super 3V2 and I do this because this models is perfect for situations that require very close to rear wall placements such as desktop systems and on wall applications for HT.

Check out this link from my manufacturer about the ports I use now.
http://www.psp-inc.com/psp-inc.com/public_html/why.htm

I have switched to the Precision ports a while ago and they just sound better than non-flared ports. There is less noise and the also enhance the bass in terms of congestion.

Hi woodsyi,

Not a big wine drinker, but I do prefer the California wines when I can.

Talk to you soon,
Louis

Thanks Louis,

From your link "The "Precision Port™" can add an average of 3db in output if used correctly." So I gather that efficiency is a primary factor for adding ports.

Can you please comment on one more point: When changing the distance from back wall to back of speaker (say for Compact Hemp), what does this do in terms of changing the sound? Is more distance better than closer? Is say a 2 foot minimum recommended to get proper sound?

Just attempting to better understand how and what, to make it easier to understand what to try to optimize SQ.

Thanks again. Kent

[ctviggen]

Bob,

Port wine and Stilton Cheese is like foie gras and Sauterne -- one of the finest food and drink combinations of all time.  Try a good bottle of NV port like Graham tawny port 10 years or Ramos-Pinto tawny port 20 years to go with a good Stilton on water crackers.  I can't believe anyone wouldn't like it.  For vintage, 91 and 92 are drinking now and still available at good price.  Australia makes some really good NV stuff for under $20.  This is my favorite dessert after a good dinner.  If you can sneak in a good cigar it's even better but I find that hard to do in mixed company now days.

Louis, sorry for the intrusion and you can remove it.  But it is about ports. 

Thanks, I will try to remember this next time I'm shopping around for a dessert wine.  I'm trying to cut down on this type of stuff, in deference to the wife, who's pregnant and can't drink.  But perhaps after the baby comes, we can try it out.  (Or I can buy it, blatantly drink it in front of her, and scoff at her looks of admonition!  That'll cause things to go over well!)

Regarding ports (the real kind), supposedly they do help quite a bit.  My Linns have an oval port that has a rough surface.  Linn touts this as lessening the "hoot" that sometimes comes along with ports.

[woodsyi]

Thanks, I will try to remember this next time I'm shopping around for a dessert wine.  I'm trying to cut down on this type of stuff, in deference to the wife, who's pregnant and can't drink.  But perhaps after the baby comes, we can try it out.  (Or I can buy it, blatantly drink it in front of her, and scoff at her looks of admonition!  That'll cause things to go over well!)

Regarding ports (the real kind), supposedly they do help quite a bit.  My Linns have an oval port that has a rough surface.  Linn touts this as lessening the "hoot" that sometimes comes along with ports.

Congrats, Bob.

Don't mess with a pregnant wife -- you gotta keep piling points away now to cash in after the baby arrives.     One day my pregnant wife called me when I was teeing off on 13th hole and said she really wanted a pumpkin pie.  Believe me, it wasn't the season for it but I found it after hitting all the local bakeries and groceries. (I finished the round)  I got to resume my weekly golf 2 weeks after my girl was born.    Be super nice now and reap the benefits later. 

[Duke]

Hello Alwayswantmo,

I also use Precision Ports in my speakers.

The "3 dB" advantage isn't really an efficiency advantage - it's a headroom advantage.  It only comes into play at high output levels.  At high output levels a lot of air has to move through the port, and the port starts to log-jam due to turbulence at the openings on either end.  The flared end sections facilitate smooth airflow at either end of the port, reducing the turbulence-induced airflow log-jam to the tune of 3 dB less compression (greater maximum output) at the port's tuning frequency.  So you have less power compression at very high output levels.

The flared ends may reduce "talking through a cardboard tube" midrange colorations - I'm not sure.  Another way of addressing this is to cut the inner opening of the port at a sharp angle, instead of straight across.

Regarding rear-ported speakers and proximity to the wall, as long as the tonal balance is still good don't worry about it.  You'd have to place the speakers within about one port diameter's distance from the wall to significantly alter the tuning, and even then you'd be moving the tuning in the right direction - lower.

If you have to place a rear-ported speaker close to the wall and it starts to get boomy, try packing the port with drinking straws cut to a little bit longer than the actual port length.  Pack them in tightly until they deform into a honeycomb shape.  This will lower the port tuning frequency, hopefully transforming what was "boom" into deeper bass extension.  Of course you'll lose the benefit of the flared port ends, but Louis's ports start out large enough in diameter that you'll probably be okay in that area unless you really push them hard.

Just my opinion.

Duke

[Alwayswantmore]

Hello Alwayswantmo,

I also use Precision Ports in my speakers.

The "3 dB" advantage isn't really an efficiency advantage - it's a headroom advantage.  It only comes into play at high output levels.  At high output levels a lot of air has to move through the port, and the port starts to log-jam due to turbulence at the openings on either end.  The flared end sections facilitate smooth airflow at either end of the port, reducing the turbulence-induced airflow log-jam to the tune of 3 dB less compression (greater maximum output) at the port's tuning frequency.  So you have less power compression at very high output levels.

The flared ends may reduce "talking through a cardboard tube" midrange colorations - I'm not sure.  Another way of addressing this is to cut the inner opening of the port at a sharp angle, instead of straight across.

Regarding rear-ported speakers and proximity to the wall, as long as the tonal balance is still good don't worry about it.  You'd have to place the speakers within about one port diameter's distance from the wall to significantly alter the tuning, and even then you'd be moving the tuning in the right direction - lower.

If you have to place a rear-ported speaker close to the wall and it starts to get boomy, try packing the port with drinking straws cut to a little bit longer than the actual port length.  Pack them in tightly until they deform into a honeycomb shape.  This will lower the port tuning frequency, hopefully transforming what was "boom" into deeper bass extension.  Of course you'll lose the benefit of the flared port ends, but Louis's ports start out large enough in diameter that you'll probably be okay in that area unless you really push them hard.

Just my opinion.

Duke

Thanks Duke for the informative answer. Kent

[Louis O]

Hi Kent,

Duke nailed it with the placement to the rear wall. In my room and all rooms are different I try to achieve a smooth balance in the bass region. Too close will get boomy for sure.

Hi Duke,

Back in my multiway days I had one model with one turn in the port tube. This was the only speaker I could use this type of port and it made a huge difference. The Precision Ports are excellent and glad that you like them in your designs.

Thanks again,
Louis