-remember: you've typically got about -5db of baffle-step loss, but you'll effectively gain about +6db from a parallel wiring of two drivers (..amp-output-impedance and current/power-supply capability dependent).
You'll also typically have up to almost +3db of floor gain at lower freq.s. depending on how close a woofer is to the floor relative to any freq..
Plus, you'll often have a bit of baffle-diffractive gain for the midrange.
Finally, depending on the crossover - midrange's are often a "composite" of woofer-mid.-tweet: meaning that if the woofer and tweeter are higher in efficiency and their crossover slope is a lower order design that you typically have a higher eff. result than the midrange alone. (..sort of like the B&O "filler" driver approach.)
No, it's not at all complex..
It would likely need a significant commitment from you to get the process going and keep it together if it is to be successful. If you are largely neutral then it is unlikely anyone else will pick up the task of driving a group project along.
For myself I would be interested in observing how a group project might evolve compared with others, probably contributing a bit here and there to the mechanical and acoustic design but have no interest in passive crossovers and no interest in building floorstanding speakers for my own use until I move back into a house with a decent sized living room. Others on the forum appear strongly interested in the details of passive crossover design and, given the popularity of the configuration and the use of standard range drivers and parts rather then expensive exotic ones, others are fairly likely to build a well documented and well engineered design.
MJK is proposing serial 4 ohm woofers not parallel ones and to use an 8 ohm midrange. He also wants/expects the speaker to be reasonably sensitive. Nothing wrong with this as a starting point so long as he then works it through to understand the consequences. It will give him a better understanding of why experienced designers using his 3 way configuration make rather different choices.
-remember: you've typically got about -5db of baffle-step loss, but you'll effectively gain about +6db from a parallel wiring of two drivers (..amp-output-impedance and current/power-supply capability dependent).
You'll also typically have up to almost +3db of floor gain at lower freq.s. depending on how close a woofer is to the floor relative to any freq..
Plus, you'll often have a bit of baffle-diffractive gain for the midrange.
Finally, depending on the crossover - midrange's are often a "composite" of woofer-mid.-tweet: meaning that if the woofer and tweeter are higher in efficiency and their crossover slope is a lower order design that you typically have a higher eff. result than the midrange alone. (..sort of like the B&O "filler" driver approach.)
No, it's not at all complex..
Hmm. I think I need to take one question at a time to not entangle everything in each other.
1. If going 0.5 is out of the question, and baffle width is decided to be 30 cm, what other ways of handling baffle step exists?
2. If more than one way exists, what way has the least amount of negative concequenses?
3. I'm. Struggling to see what the concequenses would be..
Could you please explain?
What way does experienced designer most often take when it comes to this speaker layout? 8 ogm nominal and high efficiency is what I would like to have, but it isn't decided upon, still possible to change.
It would be nice to have these questions somewhat separate, even if they are in some place connected.
Easier to get a grip on then. For me at least.
Physics dictates a strict trade-off between size, sensitivity and bass extension often known as Hofmann's Iron Law. If you want the size, sensitivity and bass extension of typical well engineered home audio speakers with 2 x 8" woofers, 5" midrange and 1" tweeter you will have to adopt roughly the same balance of compromises.
By initially concentrating on brands for the midrange you are not in a position to know what your tradeoff and constraints are. This is why an experienced designer would produce a spec first and then iterate it as analysis brings out what can be traded for what and where the sweet spot lies for the intended design.
You have part of a spec: 8 ohms, 2 x 8" woofer, 5" midrange, 1" tweeter, cabinet size, baffle width but some quantities like desired sensitivity, desired bass extension (ported/sealed) still missing. Sitting down with some design software, an initial choice of drivers and working through a simulation will bring out everything that is missing and put you in a position to explore the trade-offs.
As I mentioned earlier, to answer this look at the good designs with this configuration from the larger home audio manufacturers like Revel, Sony,...
Did he propose 2x 4 ohm series?
I know he proposed 8 ohm mid.. I recommended the 2x 8 ohms in parallel (and in my statement above: parallel) ..and a 4 ohm midrange with impedance compensation.
So then:
2x 4 ohms in series effectively give no net gain (or loss). (Voltage loss of -3db and acoustic gain of +3db = 0.)
Last edited:
It doesn't worth 260€/piece. Pair of Dayton RSS210 can be bought for the price of one Wavecore with no apparent difference in performance.
While we are at it? Posted in the wrong thread?
What in your question has to do with a ~5" driver used as a dedicated mid?
As for the topic on hand, I'll be thinking some and will post again soon.
I did a spec sheet of what I've wanted out of this speaker such as extension downwards, box volume and so on, but decided it would be nice to not be so locked up at the beginning. Maybe I should find that paper and go thru it again and post it.
Volume, preferably under or around 75L. But, bigger is possible. Downwards, the extension I would like to have is usable 30hz, 25hz would be even better but not a must, more like icing on the cake. That's around the lower limit of the music I usually listen to, 30hz that is. Yes it's electro music.
If by usable you mean -3dB at 30Hz it is a big ask of 8" drivers, even a pair of them. Some of the older Vifa woofers I have will do it but only with massive and steep cut offs at 25Hz and with big vents
Does your amplifier set-up have such subsonic protection built in?
I must have missed the information but I would [ and do] use a pair or triplet of subwoofers for the last bass octave.
My 11YO grand daughter has good ears and thinks the last cheap build was "excellent" and that was the cheap Peerless 830656 and it can play plenty loud and clean up to its thermal limit
Does your amplifier set-up have such subsonic protection built in?
I must have missed the information but I would [ and do] use a pair or triplet of subwoofers for the last bass octave.
My 11YO grand daughter has good ears and thinks the last cheap build was "excellent" and that was the cheap Peerless 830656 and it can play plenty loud and clean up to its thermal limit
None of them gets to around F3<=45Hz anechoic. I'm not inclined on making loudspeakers that will be room specific, so while some of these woofers would work in some rooms, in other (larger) it wouldn't or would be very different performance. Thanks.
Two Scans will not work their best in closed cabinet nor will they get low enough. I'm guessing you wanted to write SB34NRX75-6 ? It's a good one and will be very good woofer in a closed volume of around 70 liters - if TS parameters from SBacoustics is to be trusted.
I know about the Beyma 12BR70 but in Beyma they've made a mess with revisions and model naming. There are 3 variants of 12BR70 and only one will work in closed cabinet of around 100 liters (if i remember correctly from when i simulated its response, it was a long time ago) so it's hit and miss with it.
Thread hijacking wasn't my intention since i thought you will need a woofer or two soon or a later, so you too will benefit from slight diverge from subject. If you are bothered that much by these few posts, please do contact the moderators and i'm sure they will separate it to a different thread.
This is an interesting 5 inch midrange, http://www.phlaudio.com/products/?n...oducts&cHash=729cb2728ad943f4bd723e70ac8b09db
I have never heard one but I have heard and used older PHL divers and they have always sounded great.
PHL is a strict OEM company, but you can buy their drivers here:
PHL 1660/E172 - WAR Audio l Online Store
I used a pair of these 1660 midrange crossed over from a PD 1550 bass at 350 Hz to a Beyma TPL from 2.2KHz... Hard to beat in my (limited) experience.
Cheers
A.
I have never heard one but I have heard and used older PHL divers and they have always sounded great.
PHL is a strict OEM company, but you can buy their drivers here:
PHL 1660/E172 - WAR Audio l Online Store
I used a pair of these 1660 midrange crossed over from a PD 1550 bass at 350 Hz to a Beyma TPL from 2.2KHz... Hard to beat in my (limited) experience.
Cheers
A.
Last edited:
