I designed a tapped horn using Hornresp and folded it using Sketchup. I feel like something didn't turn out quite right along the way - I mean it sounds decent, but it is fairly far off from what I was expecting.
First, the hardware:
Spidf into Insignia amp/receiver which has a sub out -> dbx 223XL crossover -> Peavey CS400
(The crossover is used to manage the gain on the sub; going straight into Peavey from the Insignia results in extremely quiet bass, even at full sub volume on the receiver.)
Sundown E-15 V2 D2 (wired at 4 ohms; amp does ~200w at 4 ohm)
Room: 15 x 14 with a 3.5 x 4.5 extension with a sink and cabinet; shown in ASCII art (x is the current sub location):
Enclosure design is attached as an image (Sketchup available if needed). The attached "Tapped.png" shows what I intended to built vs what actually resulted (things I didn't account for in the original design, plus any measurement error). The box should be well sealed as there are screws roughly every 3 inches and liquid nails was used (had some left over from when we built our barn).
So, by the looks of hit, I should be roughly around 127 db between 25-60 hz at 1 meter at 200 watts (which I'm hitting according to my multimeter).
Well, my SPL meter hits about 120-122 right in the mouth of the sub at C weighting and about 105-110 from one meter. Now, I'm already aware that reality seems to yield lower SPL results and less flatness (due to a variety of factors) based on what I've seen in project threads, but this difference is pretty huge. The sub is in a corner as shown in the attached image (I've also tried pointing the throat into the corner and it improved the results, but certainly not to 127 db; I think it was like 110-115?).
The meters accuracy isn't a problem either - I had a Peavey cabinet before (two black widow 15s @ 200w each) pointed into the corner. I mapped the performance in Hornresp (attached) which closely matches the acoustic chart shown in the manual for the Peavey cabinet (can't remember the specific model right now). Playing music, I could hit about 115-120 on the Peavey cabinet - playing similar music on the tapped horn I hit 110; based on the acoustic chart comparison of the black widow enclosure vs the tapped horn, the tapped horn should be mopping the floor with the widows (especially on the low end, and indeed the lows are a lot more powerful, but nothing between 20-60 hz is as loud as it should be).
So - I just threw a lot of information at you (assuming your still reading); to put the issue concisely - my tapped horn should generally be quite a bit louder than the Peavey enclosure, or at the very least compete, but I'm just not feeling the same presence. The Peavey is still at my parents house (I'm still in college; let's not laugh at the cliche of the basshead college student
), so I can use the Peavey in conjunction with the tapped horn, but the problem of the tapped horn's incorrect output is still a problem I want to try and resolve if possible. This is not my first sub build, but it is my first tapped horn (basically I saw a few forums, this one including, talking about how awesome they are and I wanted to take on the challenge). Does anybody with more experience have some suggestions? I don't want all the time and money I put into this build to feel like a waste (I mean, it works, but it is quite underwhelming :/).
[Apologies for such a long post; I wanted to prevent as much relevant information as possible.]