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Tizman

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  1. Here are a couple of REW screenshots comparing the bass response of my La Scalas to my two ways with Eminence Kappa 15C in a Peavey FH-1. The two speakers were measured in the same position with the microphone at the same height and pointing at the mid horn for the La Scalas, and the HF horn for my two ways. The microphone was 4' from the speakers. I understand that the 15C gives up a few DB at the bottom in exchange for better performance at the top of its range, but this measurement shows a drop of more than a few DBs. Subjectively, my two way is obviously bass shy compared to the La Scala. My question is whether this is normal, or not? Is this due to my improperly installing the 15Cs in the cabinets, or is this the missing "few DB at the bottom" that is normal? Any insight would be much appreciated. La Scala is red and 15C in FH-1 is green.
  2. Just a quick question about installing the 15C in a La Scala or FH1. When installing, did you replace the gasket that came with the 15C? The way that the 15C is installed in a La Scala or a FH1 is against its front face. While the 15C has a nice gasket that will seal it nicely if it is mounted on the outside of a cabinet, the front gasket that is used is cut out around the screw holes, and looks like it could easily leak air. I ask because I have installed a pair in FH1s, and my measurements with REW show a large drop starting at 75 Hz or so as compared to a stock La Scala bin. The measured drop is also obvious when listening. I know that the 15C gives up a few HZ in extension compared to a K-33, but this is a lot more than a few HZ. Could this be an issue with my installed 15Cs leaking air around the gasket?
  3. Thanks Chris. I think that I can use delay on the midrange and tweeter relative to the Incoming signal feeding the bass bin to get all three in alignment.
  4. Hi All. This is a great thread that has been very informative and helpful. I do have a question that I don't think was covered so far. I have a 2 in/4 out electronic crossover, the XTA DP200 and would like to use it as a crossover for the tweeter and mid-range horns in a La Scala that will allow me to time align them. My plan is to run the bass horn through its stock passive crossover (AL-3) and then use the XTA DP200 to feed the tweeter and mid-range. Is this not preferable to using the DP200 to split the signal between LF and MF/HF and using the passive to split the frequencies going to the mid-range horn and tweeter? Any thoughts and input you all may have would be most appreciated.
  5. Chris uses 3 subs in his setup, and says that this minimizes nulls. While this may not get the job done entirely, perhaps this combined with aggressive bass trapping may be the best practical solution. Has anyone successfully applied the DBA setup? It would appear, based on Chris's quote above, that he does not use DBA in his setup. If I am reading Chris's quote correctly, he is using the equivalent of three subs along the front wall and not a DBA, and that this is sufficient for his setup.
  6. Thanks for the clarification. It would appear that the solution is room treatments or a DBA. On ChrisA’s suggestion, I read up on DBAs. My concern with them, based on my reading, is that there will be so much stuff in the room that will interfere with the operation of a DBA that it may not work properly. This is based on what I read, as I have no real world experience with them. Perhaps a DBA would work out to be the best real world solution.. It certainly appears to be the lease intrusive and most elegant solution.
  7. Thanks for the reference Chris. I'm not sure how effective I can make it given that the room will contain 60 people or so, and the furniture required to seat these people, in addition to a lot of other stuff. I may have to make do with a very large bass absorber on the back wall, even though the DBA would be an elegant and far less intrusive solution. 60 people would also make for a pretty good bass absorber. A very inconsistent one though....
  8. Yes. A proper straight 20 HZ horn is house size. If I understand this correctly, and I may not, lots of horns have output at 20 HZ, but do not control directivity at that frequency. Given my ceiling height of 10 feet/3 meters as a limitation, I can build a horn where directivity is controlled to about 57 HZ in the vertical. Horizontally, I can build a horn where directivity is controlled to around 19 HZ. Either way, there will be lots of output at 20HZ. I understand that there may be better ways to do this, and thanks ChrisA for your suggestion that I look at DBA and the SPUDS. I will do so. My goal here is to get the best sound possible in this room, and have it all be horn loaded. This project will prioritize SQ above any other criteria. There will be extensive acoustic treatments used in the room. For example, if I need to take up 10’ at the other end of the room for bass traps, it will be done. The goal is to have as large a sweet spot as possible, with the best SQ possible. All other criteria are far less important.
  9. I always thought that anything other than a full size horn was a compromise, with the various negatives associated to this compromise. My understanding is that the only reason that full size horns are not built is because they are too big for most situations, not because they are not the best way to go SQ wise. I am in the unusual situation of being able to build a full size horn. Or two if that will give a better result. I feel that this is a good thing.
  10. I don’t think that this is the case. What I am trying to figure out is if having horn subwoofers that have directivity at these lower frequencies changes any requirements for the setup of my room. Specifically, will using a horn subwoofer with directivity down to 20HZ allow for a setup that uses one such horn instead of two. How will room modes be affected by using one as opposed to two? In a general sense, how does a horn subwoofer that is directional to 20HZ and whose mouth is flush with the front wall behave differently with respect to room modes as compared to a regular direct radiator sub?
  11. ChrisA and WMcD: Thank you very much for your replies. In my drawing, I show the wall at the bottom creating a room of 8' X 30'. This was for the purpose of showing a specific example. However, this room is not built yet, and I do have a clean 30' X 50' room to work with. I can put the horn entirely behind this wall, or fold the horn somewhat so it fits in the corner. Either way, I can have the mouth come out at the boundary, rather than at some point beyond the boundary, in order to avoid back wall cancellations as referred to by ChrisA.... 1 meter is roughly a half wavelength of 170 HZ. The horn mouth that I can use in this room can be as much as 3 meters high, by whatever width I choose. If I make it also 3 meters wide, the half wavelength is around 57 HZ for both width and height. 57 HZ not a subwoofer frequency, but if this system was high-passed with a steep filter at 57 HZ, what would the result be with respect to room modes? Would a single horn subwoofer placed in the middle pose more problems than one in each corner with respect to room modes? I could also I make the horn mouth 3 meters high by 5 meters wide, for example, if that helps the improve the directivity at a lower frequency. 3 meters is 57 HZ and 5 meters is 34 HZ half wavelength respectively. I can make a very big mouth for this horn. If I use a single horn in the middle of the room, as in example "B", it can be 30' wide as in example "C". 30' is roughly 9 meters, which corresponds to 19 HZ half wavelength. Attached is another drawing that takes into account the responses of Chris A and WMcD. In these drawings, assume the use of horn mouths that are a minimum of 3 meters in height and width. Example "C" uses the entire width of the room for the horn mouth, and the entire height, but could use a smaller portion of the width if that will result in a better outcome. "C" might seem crazy, but it is in fact entirely doable. Once again, your comments and insight are much appreciated.
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