Plugging Speaker Ports

[mralexny]

Hi I'm Alex
I recently purchased a set of Polk Audio RTI A7's.
I brought them mainly for music playback but soon found out that they perform better in a HT configuration.

I later found out (through pain staking research) that plugging the ports (lower front and rear for bass and upper front for mids) would tighten the response of the drivers an turn them into a set of awesome music playback speakers; and it did.

I started with socks then move to form the I had custom made.

My question is can I use rubber stoppers instead of sock or foam?
I feel that this will prevent any air from escaping causing an even tighter driver response and turn the enclosure into a totally seal cabinet.

Side Note:
I have a Cerwin Vega cv-1800 amp (connected via a Nad 1155 preamp and im using an Ipad 3 for a Jukebox) that has more than enough power to drive them in this configuration; and as far a tv viewing I saw Battleship the other day and it was as good if not better than being at the theater.

Thank in advance

[nhhiep]

this is interesting. Currently using Rti and Lsi speakers. I thought the reason why Rti isn't as good as Lsi for music is because of the tweeter (bright), not midrange or bass.

yeah, Rti speakers are really good for HT

[Face]

I presume you're using a sub? By plugging the ports you're killing the A7's low end response. As for how much, it depends on the driver parameters and enclosure size.

Rubber stopper vs. foam, not a big difference.

[mralexny]

I can barely go past the flat zone(50%) on the preamp without the bass overpowering the overall sound. NO SUB...
The bass hits hard and tight(you feel it coming right at you---awesome for movies) ;and the mids have great clarity and transition.

Amp set to full
Preamp volume 3 sometimes 4 any higher I'll have to start charging club admission fees.lol

I'm going to order the stoppers this week.

[mralexny]

With my current configuraton I find the tweeter hi's to be right on.
I can always tone them down a bit if I need to. I try to run flat as much as possible but some digital files need a little tweaking from time to time.

[Face]

Are your speakers near boundaries(rear/side walls)?

The woofers in the A7 probably have a high QTS.

[mralexny]

Are your speakers near boundaries(rear/side walls)?

The woofers in the A7 probably have a high QTS.

Yes on both counts

[cnh]

Welcome to Club Polk!

I have to agree with Mike, above. I've never heard anyone complain about lack of tightness on Rti bass. I have both versions of the bookshelves and the last thing I'd consider doing is plugging up their ports. These speakers already have a lot of R&D that went directly into those slim front ports and rear power ports?

But whatever floats your boat. I'd mess around with room placement first, though!

cnh

[mralexny]

Welcome to Club Polk!

I have to agree with Mike, above. I've never heard anyone complain about lack of tightness on Rti bass. I have both versions of the bookshelves and the last thing I'd consider doing is plugging up their ports. These speakers already have a lot of R&D that went directly into those slim front ports and rear power ports?

But whatever floats your boat. I'd mess around with room placement first, though!

cnh

Hearing the music and feeling it are 2 different things.
I feel the mods I did brought the music to life.
Remember Im not using them for home theater even though I may watch a movie on them once in while.
I couldnt feel the music before I modded them.
If you search around you'll find that alot of people have modified not just these but other speakers including small bookshelves.
I also applied this mod to my Bose 301's and I can tell you that in all the years I've owned them they never sound so good.

But everyone doesnt heat things the same as others. To each his or her own I guess.
I appreciate the feed back.

Quote
"By their own nature, resonant systems cannot start and stop instantly. Ported speakers stagger two resonances, one from the driver and boxed air and another from the boxed air and port, in order to achieve their bass output, a more complex case than an equivalent sealed box. This causes increased time delay (increased group delay imposed by the twin resonances), both in the commencement of bass output and in its cessation. Therefore a flat steady-state bass response does not occur at the same time as the rest of the sonic output; rather, it starts later (lags) and accumulates over time as a longish resonant "tail". Because of this complex, frequency-dependent loading, ported enclosures generally result in poorer transient response at low frequencies than in well-designed sealed box systems"

[Face]

Welcome to Club Polk!

I have to agree with Mike, above. I've never heard anyone complain about lack of tightness on Rti bass. I have both versions of the bookshelves and the last thing I'd consider doing is plugging up their ports. These speakers already have a lot of R&D that went directly into those slim front ports and rear power ports?

But whatever floats your boat. I'd mess around with room placement first, though!

cnh

Since his speakers are corner loaded, it will explain why they sound better sealed. Generally, placing speakers near a boundary will reinforce low frequencies below 300(ish)hz, and will make them sound bloated if they were not designed for near wall use. Sealing them will cause the low end to roll off sooner, removing the bloated sound.

Hearing the music and feeling it are 2 different things.
I feel the mods I did brought the music to life.
Remember Im not using them for home theater even though I may watch a movie on them once in while.
I couldnt feel the music before I modded them.
If you search around you'll find that alot of people have modified not just these but other speakers including small bookshelves.
I also applied this mod to my Bose 301's and I can tell you that in all the years I've owned them they never sound so good.

But everyone doesnt heat things the same as others. To each his or her own I guess.
I appreciate the feed back.

Quote
"By their own nature, resonant systems cannot start and stop instantly. Ported speakers stagger two resonances, one from the driver and boxed air and another from the boxed air and port, in order to achieve their bass output, a more complex case than an equivalent sealed box. This causes increased time delay (increased group delay imposed by the twin resonances), both in the commencement of bass output and in its cessation. Therefore a flat steady-state bass response does not occur at the same time as the rest of the sonic output; rather, it starts later (lags) and accumulates over time as a longish resonant "tail". Because of this complex, frequency-dependent loading, ported enclosures generally result in poorer transient response at low frequencies than in well-designed sealed box systems"

Yes, but not the entire reason why they now sound better.

[mralexny]

Ok guys
Last night I pulled all the plugs and I agree they sounded alot better than when I first got them.(not as boomy)
Most likely cause they have had alot of time to breakin. But the base hits felt as if they were coming from the room and not from the front of the speakers directed at me. In other words I couldnt feel the bass hit on me. The mids also were not as clear and pronounced especially when I switched to the Yankee game. Saturday I heard a couple of thump monitor 2 way speakers(sealed enclosure) in an outdoor enviroment with no wall behind them and I could feel the bass hits. I think its all about the way you want to experience the music you listen to; in other words subjective. I am however going to leave the plugs out for the rest of the week and see how it goes it could just be a listening curve for me. (me keeping an open mind or ear..lol) I'll keep you posted.
Thanks

[mralexny]

Hey guys
Well the weekend is over; hope you all had a good one.
Ok so here the thing I put the form plugs back in cause it definitly sounds much better.
I also order thse rubber 3" and 1.2" inch stoppers to completely seal the cabinet bass and mid ports.
Should get them this week.

More to follow...

[zingo]

B&W provides foam port plugs on some of their models to tune the bass response. It's a good principle for tuning a speaker to a room, and more power to you if you like the outcome.

[PolkieMan]

Interesting that they spend all the time and research and it sounds better plugged.
Kinda makes you want to just go select the parts and just build your own.
Maybe it's because people expect that boomy sound some of the cars in the neighbor hood are like that.

[mralexny]

When I decided to upgrade my old audio system I should have done more research on the type of speakers my paticular listen style of music required as well as what to expect from the 2 basic types of speaker enclosures. In hiensite I would of gotten a set of sealed enclosure 2 or 3 way speakers with at least 12 to 15 inch woofers by Cerwin Vega or even Thump to name a couple.
Im sure for HT purposes these speakers out perform themselves; if thats even possible. And of course different strokes for different folks. Some people might like the boomyness. I prefer the more directed and tighter bass and midrange respone i'm getting with the plugs in place. They'll probably end up in my living room one day attached to that Pioneer Elite 52 I brought; setup up in a HT configuration maybe 5.1. But for now I'll just plug um and use um. lol..

[mralexny]

Update

So after installing the solid rubber stoppers both in the front an rear for sub ports and in the upper front mid port and the spearkers sounded lifeless. I had to really crank them up just to get some semi decent sound; by then they were to loud to enjoy.

I removed the front plugs yesterday and today I will remove the rear plugs.

I plan to reinstall the form plugs I started out with since I thought they really sounded great that way but I had to try the plugs for a totally sealed enclosure experience.

As before I'll keep you posted...

[steveinaz]

Maybe try just foam-plugging the rear port, since you appear to be close to boundries.

[drumminman]

Sounds to me like placement and room acoustics (shape of room, height of ceiling, placement of speakers, etc.) are playing a big role in the sound. Have you considered room treatments?

[steveinaz]

You'd be amazed what just a few inches can do to tighten up bass.

[mralexny]

Maybe try just foam-plugging the rear port, since you appear to be close to boundries.

Tried that and it was still boomy and not at all tighter.

[mralexny]

Sounds to me like placement and room acoustics (shape of room, height of ceiling, placement of speakers, etc.) are playing a big role in the sound. Have you considered room treatments?

Rooms to small and there is a lot of furniture close together.

[mralexny]

You'd be amazed what just a few inches can do to tighten up bass.

Rooms to small and there is a lot of furniture close together