BP4 and parallel BP6 input options have now been added to Hornresp.
http://www.diyaudio.com/forums/subwoofers/119854-hornresp-856.html#post5523158
Change to a centered tweeter, 2way BR
When I first build this 2way BR (pic#1 left side), I offset the tweeter to reduce the effects of baffle diffraction. I used Jeff Bagby's "Baffle Edge Diffraction Simulator" v1.2 hoping to reduced some diffraction effects and get a smoother response. The problem is the tweeter is not that smooth itself, and I don't like the asymmetric polar response. Easy to change.
I use 2cm (3/4") particle board (sawdust + glue) so repairing a hole is easy. I moved the tweeter back to the center and shifted the tweeter XO down to cover some bumps in the woofer response. Sounds good but my cheap XO components and limited budget is preventing it from sounding better.
Graphs below are the driver responses near field, and the speaker performance stepping out to 1m so you can gradually see the room influence.
When I first build this 2way BR (pic#1 left side), I offset the tweeter to reduce the effects of baffle diffraction. I used Jeff Bagby's "Baffle Edge Diffraction Simulator" v1.2 hoping to reduced some diffraction effects and get a smoother response. The problem is the tweeter is not that smooth itself, and I don't like the asymmetric polar response. Easy to change.
I use 2cm (3/4") particle board (sawdust + glue) so repairing a hole is easy. I moved the tweeter back to the center and shifted the tweeter XO down to cover some bumps in the woofer response. Sounds good but my cheap XO components and limited budget is preventing it from sounding better.
Graphs below are the driver responses near field, and the speaker performance stepping out to 1m so you can gradually see the room influence.
Attachments
Last edited:
Looks very good! When I did my MTM's I thought about offseting the tweeters, but in the end after some reading decided that the off axis irregularities were not a compromise I wanted to take.
I wish I had more time and resources available to have actually built something for the challenge. A very clever design DonVK!
Tony.
I wish I had more time and resources available to have actually built something for the challenge. A very clever design DonVK!
Tony.
There will be nothing from me, I have a no new purchases ban over my head (not a bad thing really), bunchload of meetings and stuff happening almost constantly after work hours. No time. The drivers I have to build a compact design is TB W6-1139 neo version and SB Acoustics SB65WBAC25-4, so way over budget. Will be using a TPA3251 in SE mode + one of the regular miniDSP units I have, that certainly does not help me keep budget...
yeah 9/1 came and went, I was on vacation lol. Looks like DonVK wins most of the internet points. I want to claim a few for actually building something even though I never got past the 'this sounds pretty good for $30! I have been playing with powering them from a PAM8493 as well and am SHOCKED how good a $0.20 amplifier costs. The banana plugs and mentos box cost an order of magnitude more than the amp board!
Definitely a success even if only two parties posted builds! That's two builds (actually three as DonVK did two different ones if I remember correctly) that wouldn't have seen the light of day without this thread!
I'd still like to build what I was simming earlier on, but it will be a long time coming.
Tony.
I'd still like to build what I was simming earlier on, but it will be a long time coming.
Tony.
I'm happy that I tried it, thanks for suggesting it @Jared. Normally I would not have bought drivers in this price range or tried some of these designs.
As per @wintermute , I can guarantee these would not have seen the light of day without a reason like a contest. I was pleasantly surprised.
My parts are always recylced or repurposed. This may look familar
Modular active 3 way - work in progress
As per @wintermute , I can guarantee these would not have seen the light of day without a reason like a contest. I was pleasantly surprised.
My parts are always recylced or repurposed. This may look familar
Modular active 3 way - work in progress
I preferred the 2way BR with electrical XO. BTW thanks @drewmc for the improvement suggestions on the BP6 version.
Both designs work and are very listenable, and surprising for $30, but they both have their flaws and some explanation is required. In the 100Hz-500KHz range the TC6028 sounds better than one PC83 and in the >3Khz range the TD20F sounds better than the PC83. In the <80Hz range the TC6028 BP6 sounds better than the TC6028 BR.
I tried to use the pure acoustic roll offs that are inherent in both designs to reduce component costs. The BP6+Fullrange has 3 pure acoustic slopes, while the 2way has 1 pure acoustic slope + 2 electrical slopes. The pure acoustic slopes, like the sealed Fullrange LF rolloff at 180Hz, are due to decreased efficiency. The same power is going to the driver at LF and it still moves alot, generates decreasing output, can exceed Xmax and the SQ suffers. You would not notice that SQ issue from the swept sine FR test. It also occurs in the BP6 below its VLF rolloff (needs a HP to prevent low power Xmax) and above its LF rolloff (MF residue, needs a LP). Music with a high VLF content would unload the TC6028 (both BP6 and BR), xmax may be exceeded, and SQ would suffer across its entire range. I was not expecting the "in band" SQ to suffer as the drivers see their "out of band" frequencies, and I was incorrectly expecting just an acoustic efficiency drop.
The 2way electrical XO actually decreases the power to the drivers in the range where they misbehave (out of band). So less misbehaviour and the SQ is better. In my next project (modular 3way) I plan on making the electrical XO dominant to avoid using the pure acoustic slopes. So every driver will have a bandpass and will only be fully powered for its intended "in band" well behaved range.
Both designs work and are very listenable, and surprising for $30, but they both have their flaws and some explanation is required. In the 100Hz-500KHz range the TC6028 sounds better than one PC83 and in the >3Khz range the TD20F sounds better than the PC83. In the <80Hz range the TC6028 BP6 sounds better than the TC6028 BR.
I tried to use the pure acoustic roll offs that are inherent in both designs to reduce component costs. The BP6+Fullrange has 3 pure acoustic slopes, while the 2way has 1 pure acoustic slope + 2 electrical slopes. The pure acoustic slopes, like the sealed Fullrange LF rolloff at 180Hz, are due to decreased efficiency. The same power is going to the driver at LF and it still moves alot, generates decreasing output, can exceed Xmax and the SQ suffers. You would not notice that SQ issue from the swept sine FR test. It also occurs in the BP6 below its VLF rolloff (needs a HP to prevent low power Xmax) and above its LF rolloff (MF residue, needs a LP). Music with a high VLF content would unload the TC6028 (both BP6 and BR), xmax may be exceeded, and SQ would suffer across its entire range. I was not expecting the "in band" SQ to suffer as the drivers see their "out of band" frequencies, and I was incorrectly expecting just an acoustic efficiency drop.
The 2way electrical XO actually decreases the power to the drivers in the range where they misbehave (out of band). So less misbehaviour and the SQ is better. In my next project (modular 3way) I plan on making the electrical XO dominant to avoid using the pure acoustic slopes. So every driver will have a bandpass and will only be fully powered for its intended "in band" well behaved range.
Last edited:
So I built another $30 / pair set of speakers because for some reason that price point is play money, and any higher seems like a serious problem lol.
Dayton TCP115-8 small desktop speakers
Dayton TCP115-8 small desktop speakers
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.