Does every tower need a port?

[manny11701]

I’ve loved hifi audio and have only recently been intrigued with building my own speakers.

I’m currently designing a pair with a TMM orientation, but one thing that I’ve noticed is that almost all tower speakers in the retail market have a port. Is this necessary to design a good tower speaker?

I’m still playing around with winISD, but another thing I noticed is the ports tend to be quite large on retail towers, but I the program if you use a larger port, it typically also has to be longer, so does anyone know they they’re circumventing this? (I’m assuming the internals are likely a transmission style box.

 

[fpitas]

The low frequency performance is a big selling feature, and a port usually give you another 1/2 octave. You get less cone excursion and Doppler distortion with a port, too. But if you're using a sub, often you can plug the port.

 

[fpitas]

I’m still playing around with winISD, but another thing I noticed is the ports tend to be quite large on retail towers, but I the program if you use a larger port, it typically also has to be longer, so does anyone know they they’re circumventing this? (I’m assuming the internals are likely a transmission style box.

You don't circumvent it. The taller towers tend to have transmission line effects, but the port tuning doesn't change much because of that.

 

[Gringoaudio1]

Totally depends on the parameters of what driver you are using. Research T/S (Thiel/Small) parameters. Some good introduction to speaker building books will give you the basics of Sealed vs. Ported and crossover design etc. Building a box is a skill many don’t have but it really follows from what the driver parameters tell you to build.

 

[moonlight rainbow dream]

No, ports aren't necessary. It's just the trend in modern speaker design is towards deep bass extension from relatively small boxes, and ports are the most efficient and cost-effective way to achieve that. Driver design has shifted in that direction as a consequence, and drivers that are particularly suited for sealed enclosures are not as common now.

As a DIYer you can definitely go for sealed if you want, because you are free to build really big boxes and leverage DSP (e.g. Linkwitz transform) to get more low bass out of a sealed roll-off.

 

[manny11701]

Thank you all for sharing your knowledge, I know how to plug in values into this tool, but it's clear that there's a lot to be learned on my end.

I’ve always been a fan of using subs so that speakers don't and to work as hard at producing lowend and trying to keep distortion to a minimum. I’ve been trying to be mindful of cone excursion and I did notice in the chart that it seems to have a more gradual roll with it being sealed vs ported, though this is something that I'll need to do more research on to understand how this affects the sound, because I'd imagine that it looks better with it being sealed than not, but that doesn't seem to be the case.

I’m also going to look into DSP/Linkwitz transform since this is the first time I’ve heard of it and it seems like it’d could shed some light where i have a gap in knowledge. I’ve mainly been going off of YouTube and attempting to find online forums that discuss the differences between port and sealed enclosures, but I think I’ll need to get to reading if I want these concepts to click in my head.

 

[Ron Texas]

The port provides better low frequency performance in a given size cabinet. Since the cabinet is very expensive to make an overwhelming number of speaker manufacturers use ported enclosures.

 

[fpitas]

I’m also going to look into DSP/Linkwitz transform since this is the first time I’ve heard of it and it seems like it’d could shed some light where i have a gap in knowledge. I’ve mainly been going off of YouTube and attempting to find online forums that discuss the differences between port and sealed enclosures, but I think I’ll need to get to reading if I want these concepts to click in my head.

Be careful putting in much EQ below the port tuning. The cone gets unloaded down there, and you can get destructive excursion. You can use it with sealed, but now you have to mind the Doppler distortion from excursion, if you push a poor defenseless tiny woofer to low frequencies.

One trick is to tune the port much lower than you might otherwise and use EQ above the tuning frequency.

 

[jaakkopetteri]

Do ported designs actually win in absolute output? They're more efficient, sure, but judging by some random WinISD sims it seems that they have no advantage in max SPL when port volume is accounted for

 

[manny11701]

Do ported designs actually win in absolute output? They're more efficient, sure, but judging by some random WinISD sims it seems that they have no advantage in max SPL when port volume is accounted for

That's exactly what I want to know! I've heard the basic 'ported gives you louder base, sealed gives you cleaner base' when it comes to car audio, but I learned that back when I was a kid and now that I'm looking to design my own speakers -partially for the love of hifi, partially because I'm a masochist- I want to know truly better sound wise.

I've always gone with sealed subs in my cars, because I believe in a cleaner/truer bass, but for home audio I've been buying re-used retail speakers which have all been ported and I've always used paired them with subs.

Though the scope of this post is specific to towers, I'm interested to see how overall it plays out if you have all the volume you need in an enclosure for a sealed speaker to compete with a ported one.

I will preface that I just plugged in these values and I think I did it correctly, but I'm not actually sure. For volume I just plugged in the measurements that I wanted my towers to be and then created a speaker based off the TSP provided by Parts express and the manufacturer (in this case the Hi-Vi M6N's)

 

[sarumbear]

I’m also going to look into DSP/Linkwitz transform since this is the first time I’ve heard of it and it seems like it’d could shed some light where i have a gap in knowledge.

…only works with closed boxes.

 

[fpitas]

That's exactly what I want to know! I've heard the basic 'ported gives you louder base, sealed gives you cleaner base' when it comes to car audio, but I learned that back when I was a kid and now that I'm looking to design my own speakers -partially for the love of hifi, partially because I'm a masochist- I want to know truly better sound wise.

I've always gone with sealed subs in my cars, because I believe in a cleaner/truer bass, but for home audio I've been buying re-used retail speakers which have all been ported and I've always used paired them with subs.

Though the scope of this post is specific to towers, I'm interested to see how overall it plays out if you have all the volume you need in an enclosure for a sealed speaker to compete with a ported one.

I will preface that I just plugged in these values and I think I did it correctly, but I'm not actually sure. For volume I just plugged in the measurements that I wanted my towers to be and then created a speaker based off the TSP provided by Parts express and the manufacturer (in this case the Hi-Vi M6N's)

Porting reduces excursion near the port tuning, but it doesn't increase the power handling at higher frequencies. So, it depends on what you mean by louder.

 

[manny11701]

Porting reduces excursion near the port tuning, but it doesn't increase the power handling at higher frequencies. So, it depends on what you mean by louder.

I'm not sure either, I think they meant you can sense more base presence, but it's more scattered, but a sealed box has a more direct punch. I've always leaned more towards the latter, though again, I was 16 when I heard this statement and I'm now 29, so I can't speak to the original coiner of the phrase's intentions.

 

[fpitas]

I prefer sealed, too. To that end I used 15" woofers so the excursion remains reasonable in my room.

 

[manny11701]

Be careful putting in much EQ below the port tuning. The cone gets unloaded down there, and you can get destructive excursion. You can use it with sealed, but now you have to mind the Doppler distortion from excursion, if you push a poor defenseless tiny woofer to low frequencies.

One trick is to tune the port much lower than you might otherwise and use EQ above the tuning frequency.

I see what you mean, I plugged in the default Linkwitz just to see what it'd do in WinISD, but when I look at the cone excursion, it's OFF THE CHARTS! (literally)



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[fpitas]

I see what you mean, I plugged in the default Linkwitz just to see what it'd do in WinISD, but when I look at the cone excursion, it's OFF THE CHARTS! (literally)



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Yeah. Like Sarumbear said above, you usually don't even try it with ported.

 

[manny11701]

Yeah. Like Sarumbear said above, you usually don't even try it with ported.

The yellow line is the sealed enclosure, the blue is the ported with no EQ. This is definitely a lot of fun, even just playing with these values and seeing what kind of response I can get.

 

[Digby]

I have to ask, why do you want to make towers? There are so many towers, of all different prices ranges, that it would probably be very hard to improve on commercial designs. The reason to DIY, in my opinion, is because what you want either isn't out there or is far outside your price range - something like corner horns would fit this criteria for many.

Obviously, you can do what you want, it is a free world, but I question why build towers, when they are pretty much wrapped up by the market already.

 

[manny11701]

I have to ask, why do you want to make towers? There are so many towers, of all different prices ranges, that it would probably be very hard to improve on commercial designs. The reason to DIY, in my opinion, is because what you want either isn't out there or is far outside your price range - something like corner horns would fit this criteria for many.

Obviously, you can do what you want, it is a free world, but I question why build towers, when they are pretty much wrapped up by the market already.

That’s a fair question that I’m asking myself. For me the cliche of loving a challenge and loving to learn a new skill are my main drives for this project.

I also don’t want to give someone else my money. When taking r&d and the supply chain into account, the cost of thousand+ dollar speakers can be boiled down to a few hundred dollars in components and lumber.

Also i love making friends in this community. Everyone is so passionate and willing to share their knowledge and I find that exhilarating to go one a journey and pick up friend along the way.

All and all its fun for me, but I will say sticking it to the corps adds a little more to the project, though that is further in the back of my mind for this.

 

[fpitas]

Let's hope your determination and love of a challenge doesn't falter when you reach the crossover design