Hello all,
For a while now I have been fascinated by the idea of creating a vintage-style (Pioneer HPM-100/JBL 4311 etc.) speaker utilizing DSP for the crossovers and some shelving EQ to make up for some of the shortcomings of cheap (GRS) drivers. After reading Speaker Cookbook, I came to the following targets for the speakers:
The speakers will NEVER be used loudly (above 100dB SPL), my apartment is very noisy, despite soundproofing and acoustic treatment, so the amps will have a relatively low Wattage, around 10~20 Watts. Also, these probably won't become my main speakers, I have a set of Yamaha HS7 for referencing which I am pretty happy with, the only reason for this project is: fun!
After some experimenting with VituixCAD I came to the following design, I am aware that when using miniDSP I will be able to measure and correct more accurately, but I think this gives a good idea of the boosts that need to be done in order to get this (somewhat) flat frequency response.
I have some questions about the processing though.
For a while now I have been fascinated by the idea of creating a vintage-style (Pioneer HPM-100/JBL 4311 etc.) speaker utilizing DSP for the crossovers and some shelving EQ to make up for some of the shortcomings of cheap (GRS) drivers. After reading Speaker Cookbook, I came to the following targets for the speakers:
- 3-way speaker, big woofer, smaller mid woofer and a planar tweeter (GRS 10PT-8, GRS 6PT-8, GRS PT2522-4)
- High SPL/1w@1m (92~93db SPL)
- Sealed Enclosure with 50~100% filling
- Tri-Amped with DIY JLH amps
- DSP with miniDSP
- Linear frequency response, minimal bumps
- Good low and high frequency extension, helped by DSP
The speakers will NEVER be used loudly (above 100dB SPL), my apartment is very noisy, despite soundproofing and acoustic treatment, so the amps will have a relatively low Wattage, around 10~20 Watts. Also, these probably won't become my main speakers, I have a set of Yamaha HS7 for referencing which I am pretty happy with, the only reason for this project is: fun!
After some experimenting with VituixCAD I came to the following design, I am aware that when using miniDSP I will be able to measure and correct more accurately, but I think this gives a good idea of the boosts that need to be done in order to get this (somewhat) flat frequency response.
I have some questions about the processing though.
- The woofer has some heavy boosting with 13dB shelve at 29hz and 11dB shelve at 15hz to extend the "flatness" of the frequency response down lower than it's natural resonant frequency (@47hz). Let's say the amp will be playing at 10W max, and the maximum RMS of the speaker is 200W, will the low-end boosting lead to audible distortions, or is the woofer "beefy" enough to handle the +-12.5db boosting at the low end on low volumes?
- Will there be other negative side effects to this I might be overseeing?
- Is this just a really dumb idea in general, or is there some merit to it?
With all that low-down bass boost, woofer excursion will very likely be a limiting factor - even at modest spls. This is a useful calculator:
http://www.baudline.com/erik/bass/xmaxer.html
http://www.baudline.com/erik/bass/xmaxer.html
There is indeed too much bass boost. With a sealed enclosure, aim for a Qtc and slope that complements room gain. Even if your f3 is in the 60Hz-70Hz range and seems unimpressive as modeled, it`ll likely work out better in a real room, IOW not boomy and you will not sacrifice dynamics, which is important even if your average listening SPL is not that high.
Can the minDSP do DEQ?
DEQ applies EQ but only up to a set output level, after that it is compressed
Brian
DEQ applies EQ but only up to a set output level, after that it is compressed
Brian