tapped horn design
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Category: General
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Forum Description: How Your Projects Perform
URL: https://forum.speakerplans.com/forum_posts.asp?TID=88492
Printed Date: 27 March 2026 at 5:30am
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Topic: tapped horn design
Posted By: hond
Subject: tapped horn design
Date Posted: 05 September 2014 at 12:53pm
my mate and I did our first folded bass horn design, a tapped horn around the pd 186/2 and from our first tests we can conclude that it well outperforms a pd186/2 loaded super scooper.    smoothing 1/12, green is scoop, gold is tapped horn. As you can see the scoop has an odd dip around 50Hz.. we're not sure; could have been the room (large woodshop) but the tapped horn didn't have this at all. This is just a prototype; we need to re-do the dimensions because it barely goes through a door. The fold for now is done with best sound quality and the least volume loss in the corners and smooth transitions. Next design we will try to maximize use of space. The sound quality is superb. It goes deep down to 35Hz -5 dB! incredible warm, rounded yet punchy sound. The upper bass region from 70-100 Hz isn't as heavy as a scoop but we only want to use it from 30-80Hz anyway. That's what is was designed for. The scoop sounds really harsh compared to the tapped horn. The upper bass is stronger as stated by the first measurements but when you A/B the two cabs when playing music through them there is an incredible difference! The tapped horn in one word is smoooooth and pretty fast. The scoop is harsh and slowy but has a bit more detail in the upper bass (but at the some time more fatiguing to my ear). In stacks of 4 I can only imagine this thing will go down to 30 flat easily which is incredible, I couldn't believe horn resp and couldn't believe the measurements. This tapped horn effect gives us double sd and excursion at around 40-50Hz which is the problematic region for this specific driver. Overall I'm very impressed with the sound coming from this thing... and the crazy thing is that the prototype was built out of mdf :p Proper measurements will be up when we get to measure it outdoors. So one advice: if you want to try out tapped horns yourself.. just do it! Sounds really good! |
Replies:
Posted By: Xoc1
Date Posted: 05 September 2014 at 1:44pm
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I would be interested to see your hornresp input screen if you have it. That's a big cab, so i suppose the large mouth pushes up the frequency and efficiency of the cab and stops you running out of x-max. Putting a large void in the middle of the cab makes for an easy fold but certainly does not help when trying to fit the cab though a door!
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Posted By: snowflake
Date Posted: 05 September 2014 at 3:13pm
| looks good but that's a lot of wasted space. IMO rounding the corners does absolutely nothing useful in subs and wastes volume too. the larger the volume of your horn the lower it will go. the only frequencies that the rounding will help are high frequencies i.e. distortion that you don't want a sub horn to transmit. |
Posted By: KidCreole
Date Posted: 05 September 2014 at 6:17pm
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HUGE ------------- Mykey Wattco |
Posted By: KidCreole
Date Posted: 05 September 2014 at 6:19pm
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Also for a TH that is quite a short horn. Back to the drawing board. Longer horn with no wasted space and a smaller mouth ------------- Mykey Wattco |
Posted By: odc04r
Date Posted: 05 September 2014 at 7:05pm
Nice build! Always good to see the results coming out similar to the modelling. Be interested to see what you achieve with V2. I've been simulating tapped horns for some little 200mm drivers I have again recently, it's that or a rear loaded horn. You may have just tempted me back towards the tapped - just like the look of them!
He already said in the original post that it was only a prototype, and that they were going to redesign it to maximise volume efficiency, quit being so damn negative all the time. |
KidCreole wrote:Posted By: KidCreole
Date Posted: 05 September 2014 at 7:13pm
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Yeah sorry about that. Not sure if it's being negative though. After all this is the real world and we don't live in Disneyland Maybe I just don't like wasting wood ------------- Mykey Wattco |
Posted By: hond
Date Posted: 06 September 2014 at 1:10am
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making the horn longer than the 3,4 meters it 'already' is, makes the
loading go lower and puts too much stress on the driver causing it to go
way out of the xmax and even xlim. You just can't fully load a pd 186
below 40Hz even 50Hz in a FLH is tricky without going out of xmax.
Tapped horns allow to load down to about 40 but not much more than that!
This driver is just too weak to handle those low frequencies. also tapped horns allow you to only need 1/4th wavelength to get decent loading at specific frequency (according to Danley at least - I personally haven't got a clue if this is correct) The large mouth is to help smooth out overall response and gives a little bit more overall efficiency. At first we were concerned that due to the large mouth "extension" too little of the waves of the backside of the driver would travel back inwards the horn but apparently it wasn't a problem at all. I don't really know if the large mouth helps in the design but since this cab sounds really nice I guess it does.. the only real test is to build the same design but without the last segment horn extension.  |
Posted By: Elliot Thompson
Date Posted: 06 September 2014 at 2:56pm
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Hond, your measurements are the typical response of a Scoop so there is nothing-peculiar taking place there. A gentleman on this board offered outdoor measurements and, had the same decline @ 50 Hz. I have literally carried my laptop to outdoor events and measured such bins in which the cabinets began to decline below 51.7 Hz. There is a big difference measuring a box in real-time versus using a simulation software as a means of reference. Your low midrange will just need to work a little harder to make up the loss from 70 Hz onwards that your design does not offer with great efficiency as a Scoop. Best Regards, ------------- Elliot Thompson |