Hello,
I will soon be starting to build Pensil 10p as per plan with a front port. Is the rear port an option? Would I gain or lose anything if I went with a rear port. I understand that it wouldn't make it a Pensil anymore. Just curious.My present speakers are sitting 18 inches from the front wall and 9 inches from side wall.
I will soon be starting to build Pensil 10p as per plan with a front port. Is the rear port an option? Would I gain or lose anything if I went with a rear port. I understand that it wouldn't make it a Pensil anymore. Just curious.My present speakers are sitting 18 inches from the front wall and 9 inches from side wall.
bianchi,
Rear porting the Pensil has been discussed on the forms before and it is an option. AFAIK it still remains a Pensil design as long as dimensions and placement of the port remain the same.
The rear port places might affect the speaker behavior when it comes to boundary loading, as the port becomes close to the wall - you will need experiment with the distance from the rear wall.
Rear porting the Pensil has been discussed on the forms before and it is an option. AFAIK it still remains a Pensil design as long as dimensions and placement of the port remain the same.
The rear port places might affect the speaker behavior when it comes to boundary loading, as the port becomes close to the wall - you will need experiment with the distance from the rear wall.
Great.Can you please direct me to that thread? I have tried looking for it and couldn't find a thread that touched on this specific subject and don't care to go through 501 pages to find an answer. I'm new to this forum so don't know all the search secrets.
I've been scouring the site and found a thread on the Jim Griffin MLTL design. Jim says that the port on his design can be placed on either sides without ill effects. Would the same apply to the Pensil? I haven't been able to find confirmation of this on the site.
I've exchanged emails with a member who has built the rear ported Pensil 10p and he claims that it should not be a problem. I do not wish to take a chance since my speakers will be placed very near corners and front wall.
I've exchanged emails with a member who has built the rear ported Pensil 10p and he claims that it should not be a problem. I do not wish to take a chance since my speakers will be placed very near corners and front wall.
That is the only caveat, placing it to close to a wall will screw things up. It is still a Pensil.
You can also rotate the box 90° and put the box on the “side” it is still a Pensil.
You can also change the shape of the terminus (ie a semi-circle like on the Festival Series). Still a Pensil. I have a soft spot for that shape.
Curved sides are fine, changing the aspect ratio is fine. One just has to maintain height, driver Zd, cross-section and terminus area (and depth).
dave
dave
Also Zv, Av, Lv (vent axial position to the throat, vent CSA and and vent length). But as you say, you can locate it on the rear or sides if desired. Since the laws of physics apply, it will affect the boundary loading, to what extent depending on the enclosure's position. An advantage of the pensils here is that they were designed to provide some tuning flexibility by adjusting the stuffing density.
I don't think I would be able to bring the speaker out more that 60cm from the front wall and 30cm from the side wall.Would this still cause me problems?With this placement restriction, would I gain anything by doing a rear port.
It depends how you define 'gain something'. Frankly I doubt you would obtain any acoustic advantages so really it's more a question of aesthetic preference.
If by going with a rear port I would not lose or gain anything and still be able to tune to my preference, I would go with a rear port just for, as Scottmoose said, an aesthetic preference. My speakers would definitely be boundary loaded, would it be easier for me to adjust to preference with a front or rear port? Dave seems to think that rear porting would mess things up if placed too close to the wall, but how close is close?Like I said, I don't think that I can move them more than 60cm out and 30cm sideways. Is that considered close?
Too close has to be judged in the field with your kit and your room and your preferences. Perhaps as little as a 10-20 cm gap to the wall. And with the adjustable damping, more will tamp things down allowing for placement closer to the wall.
dave
dave
So, what you are saying is that since the Pensil has adjustable damping, I can always adjust to preference whether front or back ported regardless of boundaries.
Dave said ``That is the only caveat, placing it to close to a wall will screw things up.``If I do screw things up, can I fix it with damping?
Dave said ``That is the only caveat, placing it to close to a wall will screw things up.``If I do screw things up, can I fix it with damping?
binachi,
AFAIK the designer (Scott) considered the realities of different room sizes and characteristics, placement of the speakers, choice of amplifier, personal preferences of the listener etc. and made the design with adjustable stuffing so that these could be compensated for within reasonable limit.
So, in this case, you should be able to adjust the LF output and characteristics within a reasonable range by changing distance to the wall and changing amount of fill. But your experience will somewhat depend on your room and your gear - so some experimentation will be required. There are other tricks like use of spikes - this helps tighten up the bass for some folks.
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The reason for my thread was to see if a rear port was an option. From the beginning my intentions were to build the speaker front ported as per plan. I trust the designer since he knows alot more on the subject than I do, but aesthetically I find the port in the back more appealing. I would never comprise form over function more so since this is my first build.
So my question is: If I build these speakers with the back port, all things being equal, would I still be able to tune them to perform like front ported?
So my question is: If I build these speakers with the back port, all things being equal, would I still be able to tune them to perform like front ported?
Somewhat. If too, too close nothing but pulling it out a few inches will be needed.
What Zia said.
dave
...and what Dave & Zia said. Not much more it's possible to say really. They're reasonably flexible but there's a limit. If you have significant doubts, keep the vent on the front.
This is my first build and I don't feel like experimenting. The reason I chose the Pensil 10p is strictly based on opinions on this site and the internet as a whole. If they have been enjoyed with the ports in the front, front ports it will be. I trust the designer knew what he was doing and the unanimous appreciation of the design is testament to this.
I'd like to think I knew what I was doing, although many might disagree. 😉
I designed all of the pensils with front vents as the baseline assumption, hence the fact that are drawn with the vents at the front. As stated, you can move the vent position to the rear (or sides), but if you do so, you have to be willing to be proactive should you find you have excess room interactions, which unfortunately cannot be properly assessed on a forum. Setting vent position aside, the pensils were specifically designed to be easily adjustable by the end-user by simply tailoring the amount of damping as they see fit / to their preference, so you may wish to be slightly proactive and willing to experiment anyway.
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One more question.Would a rear ported Pensil give the same results as a speaker with a rear firing passive radiator? The reason I am asking is because my current speakers are Klipsch Forte ll with a rear passive radiator. They are corner loaded at 18 inches from the front wall and 9 inches from the side walls.I like what comes out of the Klipsch, although sometimes too bright, but I was wondering if the rear ported Pensil would preform similarly????